The Avifauna of Micronesia, Its Origin, Evolution, and Distribution
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Title: The Avifauna of Micronesia, Its Origin, Evolution, and Distribution
Author: Rollin H. Baker
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*** START OF THE PROJECT GUTENBERG EBOOK THE AVIFAUNA OF MICRONESIA, ITS ORIGIN, EVOLUTION, AND DISTRIBUTION ***
UNIVERSITY OF KANSAS PUBLICATIONS
MUSEUM OF NATURAL HISTORY
VOLUME 3 · 1951
EDITORS
E. RAYMOND HALL, _Chairman_
A. BYRON LEONARD
EDWARD H. TAYLOR
ROBERT W. WILSON
MUSEUM OF NATURAL HISTORY
UNIVERSITY OF KANSAS
LAWRENCE
1951
MUSEUM OF NATURAL HISTORY
UNIVERSITY OF KANSAS
LAWRENCE
PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1951
[Illustration]
24-1811
CONTENTS
1. The Avifauna of Micronesia, Its Origin, Evolution, and Distribution.
By Rollin H. Baker. Pp. 1-359, 16 figures in text. June 12, 1951
2. A Quantitative Study of the Nocturnal Migration of Birds. By George
H. Lowery, Jr. Pp. 361-472, 47 figures in text. June 29, 1951
3. Phylogeny of the Waxwings and Allied Birds. By M. Dale Arvey. Pp.
473-530, 49 figures in text, 13 tables. October 10, 1951
4. Birds from the State of Veracruz, Mexico. By George H. Lowery, Jr.
and Walter W. Dalquest. Pp. 531-649, 7 figures in text, 2 tables.
October 10, 1951
Index, Pp. 651-681.
The Avifauna of Micronesia,
Its Origin, Evolution, and Distribution
BY
ROLLIN H. BAKER
University of Kansas Publications
Museum of Natural History
Volume 3, No. 1, pp. 1-359, 16 figures in text
June 12, 1951
University of Kansas
LAWRENCE
1951
The Avifauna of Micronesia,
Its Origin, Evolution, and Distribution
BY
ROLLIN H. BAKER
University of Kansas Publications
Museum of Natural History
Volume 3, No. 1, pp. 1-359, 16 figures in text
June 12, 1951
University of Kansas
LAWRENCE
1951
UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY
Editors: E. Raymond Hall, Chairman, A. Byron Leonard,
Edward H. Taylor, Robert W. Wilson
=Volume 3, No. 1, pp. 1-359, 16 figures in text
Published June 12, 1951=
UNIVERSITY OF KANSAS
Lawrence, Kansas
PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1951
[Illustration]
22-8131
The Avifauna of Micronesia,
Its Origin, Evolution, and Distribution
By
ROLLIN H. BAKER
CONTENTS
PAGE
INTRODUCTION 5
DESCRIPTION OF MICRONESIA 5
Climate 8
Soils 9
Surface water 9
Vegetation 10
GAZETTEER OF THE ISLANDS OF MICRONESIA 11
Mariana Islands 11
Palau Islands 13
Caroline Islands 14
Marshall Islands 15
ORNITHOLOGICAL EXPLORATION IN MICRONESIA 16
CHECK-LIST OF THE BIRDS OF MICRONESIA 21
DISCUSSION OF THE AVIFAUNA 28
Oceanic Birds 28
Inshore Oceanic Birds 29
Offshore and Pelagic Oceanic Birds 30
Faunal Components 30
Migratory Shore Birds 32
Original Homes of the Shore Birds that Visit Micronesia 32
Routes of Migration 34
Populations of Shore Birds in Micronesia 37
Land and Fresh-Water Birds 42
Polynesian Component 44
Melanesian Component 44
Moluccan and Celebesian Components 45
Philippine Component 45
Palearctic Component 46
Speciation 48
Time of Colonization 50
Factors Causing Dispersal 52
Analysis of Speciation 55
CONSERVATION OF THE AVIFAUNA OF MICRONESIA 58
THE FUTURE OF ORNITHOLOGICAL RESEARCH IN MICRONESIA 60
METHODS AND ACKNOWLEDGMENTS 60
ACCOUNTS OF THE KINDS OF BIRDS IN MICRONESIA 63
SUMMARY AND CONCLUSIONS 340
BIBLIOGRAPHY 343
FIGURES IN TEXT
FIGURE PAGE
1. The islands of Micronesia. 6
2. The Mariana Islands. 12
3. The Palau Islands. 13
4. The Caroline Islands. 15
5. The Marshall Islands. 16
6. Routes of migration used by shore birds in the Pacific. 34
7. Avifaunal regions of the central Pacific. 43
8. Faunal areas from which Micronesian birds have been derived. 46
9. Routes of dispersal of rails in the Pacific area. 120
10. Variation in length of culmen of _Sterna s. sumatrana_. 159
11. Geographic distribution of _Thalasseus bergii_. 164
12. Geographic distribution of _Gygis alba_ in the Pacific. 177
13. Distribution and dispersal of _Ptilinopus porphyraceus_. 190
14. Distribution and dispersal of _Gallicolumba_ in the Pacific. 204
15. Distribution and dispersal of _Acrocephalus_ in the Pacific. 260
16. Distribution and dispersal of _Myzomela_ in the Pacific. 316
INTRODUCTION
Birds in Micronesia comprise the most outstanding animal life of the
islands, as far as vertebrates are concerned. No fewer than 206 kinds,
belonging to 37 families and 91 genera have been found there. Although
this number upon first consideration may seem large, actually any large
land mass in the same latitude has many more kinds of birds than does
Micronesia. In this connection it is pertinent to recall that the
islands of Micronesia are oceanic and have apparently been formed
independently of any continental land mass. Thus, animal life found on
these islands has reached them by overseas migration, either by some
passive means or by individual effort. Zoogeographers have had some
difficulty in explaining the presence of snails and other nonflying
animals on isolated oceanic islands. Crampton, in his studies of the
land snails of the genus _Partula_ at Guam and Saipan (1925:10), writes,
"Despite the geological difficulties, the biological findings strongly
support the view that the dominant process in this part of Oceania has
been one of subsidence and of insular dissection." Although there exists
today some question as to how certain forms of life have reached these
remote dots of land, the ornithologist has not been much in doubt as to
the actual _means_ of arrival of birds. With the exception of six kinds
of birds which are definitely known to have been introduced by man, the
birds have apparently reached these islands by flying there from
somewhere else. The ornithologist is, therefore, concerned with learning
_from where_, _by what route_, _when_, and _why_ the various species of
birds came and _how_ they have become established on these islands of
Micronesia. These birds exist in small populations; often less than 100
individuals of one kind may be found on a small island. How have such
small numbers had the ability to survive and what environmental
adaptations have occurred, are two additional questions which confront
the student of Micronesian birds.
DESCRIPTION OF MICRONESIA
The vast expanse of the Pacific Ocean is dotted with numerous islands,
most of which are concentrated in the central and western part and are
known collectively as Oceania. Within Oceania three divisions are
popularly recognized: Melanesia, Polynesia, and Micronesia. According to
Krieger (1943:6), the Micronesia islands include the Mariana, Palau,
Caroline, Marshall, and Gilbert islands; they may take in also the
Volcano, Bonin, and Ellice islands (from the standpoint of
anthropology). Zoogeographically, according to Wallace (1876),
Micronesia is to be included in the Polynesian Subregion of the
Australian Region. Mayr (1941a:193), on the basis of the distribution of
birds, ranks Micronesia as one of the four subdivisions of the
Polynesian Subregion, and includes within Micronesia the Palau,
Caroline, Mariana, Marshall, and Gilbert islands. Except in the
discussion of distribution, this report does not treat of the avifauna
of the Gilbert Islands, which straddle the equator south of the Marshall
Islands. This report is concerned only with the birds in the Mariana,
Palau, Caroline, and Marshall islands formerly mandated to Japan, and
with the birds of the island of Guam, which is a possession of the
United States.
[Illustration: FIG. 1. The Islands of Micronesia]
The word Micronesia is, of course, derived from the Greek words _mikros_
meaning small and _nesos_ meaning island, and, as shown in figure 1,
this term is appropriate, for the islands of this area are small. For
the most part they are too small even for inclusion on standard-sized
maps of the world. There are thousands of these islands in an area some
2,400 miles long from east to west and some 1,200 miles broad from north
to south. All of the islands of Micronesia are oceanic islands; that is
to say, they have never been connected to the Asiatic continent or to
other land masses by means of land bridges.
Geologists and oceanographers have shown (see descriptions by Hobbs,
1945), that islands of Micronesia are of two general types: arcuate and
strewn. The Pacific Ocean is surrounded by rising mountain ranges which
are arranged in elongated, near-circular arcs, which form an extended
series of scallops. In the western Pacific these sweeping arcs extend
into the ocean, where the mountain ranges project upward from the bottom
of the sea with only the crests showing above the waves to point out, in
dotted outline, the position of the mountains. The easternmost of these
arcs is marked by the islands of the Aleutians, Kuriles, Japan, Izo,
Bonins, Volcanoes, Marianas, Yap, Palaus, and others continuing
southward into Melanesia. These are characterized by igneous rocks of
andesitic nature.
To the eastward of the arcuate islands in Micronesia, are numerous and
irregularly distributed islands, making up all of the central and
eastern Carolines and the Marshalls, which are known as strewn islands.
Strewn islands mark the places of former volcanoes or volcanic peaks. If
these volcanic peaks have been completely drowned and are now marked by
a series of low islands edged by a protecting reef formed by coral
growth enclosing a lagoon and with all exposures consisting of coral
rock, the island is known as a coral atoll (example, Ulithi Atoll). Some
of the coral exposures lack lagoons; they are known merely as coral
islands (example, East Fayu). Some atolls become elevated by geologic
activity and the lagoons may dry out or drain. The accumulation of guano
of oceanic birds and the residue of fish and other organisms in the area
of the lagoon remains as a rich phosphate deposit; these raised atolls
have been called phosphate islands (example, Fais). Other strewn islands
consist of igneous rocks which are exposed above the surface of the
ocean. These are known as "high" or volcanic islands and may occur as a
single mountain rising out of the ocean (example, Kusaie), or be partly
drowned and surrounded by a coral reef (example, Truk). The igneous
rocks found on these strewn islands are basaltic in nature.
The Mariana Islands consist of a chain of volcanic islands approximately
450 miles long. As shown in figure 2, there are 14 single islands and
one group of three islands (Maug), from Uracas in the north to Guam in
the south. The Palau Islands which are situated in the easternmost part
of Micronesia have often been considered from a political standpoint as
part of the Caroline Islands. As shown in figure 3, the Palau Islands
are a chain of islands approximately 120 miles long from north to south.
Sonsorol, Tobi, Merir, Pulo Anna, and Helen Island occur to the
southward of the Palaus and may be considered as part of the Carolines
or as part of the Palaus. The Palaus together with the Carolines, to the
eastward, extend in an east-west direction for approximately 1,700
miles. The Palaus and Carolines include (as shown in figures 3 and 4) 37
atolls, 34 banks, 11 coral islands without lagoons, 2 uplifted phosphate
islands, 4 volcanic islands, and the Palau chain. The Marshall Islands
to the extreme eastward extend approximately 700 miles from north to
south and, as shown in figure 5, contain 29 atolls and five coral
islands without lagoons. No volcanic exposures occur in the Marshall
Islands.
There is a total land surface of approximately 846 square miles in the
islands of Micronesia. The Palaus and Carolines have 525 square miles,
the Marianas 247 square miles, and the Marshalls 74 square miles of land
surface. Guam has the largest land surface of any of the islands of
Micronesia with 225 square miles, Ponapé has 145 square miles, and
Babelthuap has 143 square miles. Asuncion, in the northern Marianas, has
the highest elevation, rising as an almost perfect cone to a height of
2,923 feet; Ponapé reaches a height of 2,579 feet above the sea level.
The volcanic islands are known as "high" islands, and the coral atolls
are known as "low" islands. The coral islands usually rise but a few
feet above sea level.
CLIMATE
In Micronesia there are two seasons: a wet summer and a dryer winter.
Temperatures rarely go above 90° F. and rarely below 70° F. Rainfall in
the Marianas averages approximately 85 inches per year, in the Palaus
approximately 150 inches, in the Carolines it ranges from 129 to 185
inches, and in the Marshalls it goes up to 160 inches. The humidity is
excessive, the average annual mean of relative humidity for selected
islands in Micronesia being between 82 and 86 percent. The relative
humidity is lower in the western Carolines and the Palaus, than in other
parts of Micronesia.
The Mariana Islands lie between the area of the Asiatic monsoon and the
belt of the northeast trade winds. At Saipan from November until March
or April, winds usually are easterly or northeasterly and are strong and
steady since the northeast trades and the winter monsoon reinforce each
other. In April and May the directions of the winds shift toward the
southeast, and they become weaker and more variable. In this period
there may be some easterly winds in addition to the predominating
southeasterly winds. Detailed information is not available on the winds
which occur in the Marianas north of Saipan, but at Pagan easterly winds
probably prevail from May to July and westerly winds prevail in the
remainder of the year. The Carolines lie in the belt of alternating
northeast trade winds and southwest monsoons. The northeast trades begin
in October and prevail until May or June. The southwest monsoon occurs
from May to October and may be felt as far east as Truk. To the
eastward, the winds of the summer are usually light and variable. In the
Marshall Islands, the northeast trade winds predominate from about
December to April, especially in the northern part of the Marshalls. In
summer, winds are variable and weak; periods of calm may occur. Typhoons
and squalls occur most frequently in the spring and summer in
Micronesia. Some of the severe typhoons are known to engulf entire
islands, as did the one at Woleai in 1907.
SOILS
The soils of the islands of Micronesia have been derived from volcanic
materials or from depositions of coralline limestone. Volcanic soils
occur on the "high" islands of Micronesia. In many places, especially on
the islands of the northern Marianas there is little soil; there are
large areas of bare igneous rock, because the islands are geologically
of relatively recent origin and little erosion has occurred. On islands
where volcanic rocks have decomposed, the resulting soil may have a top
layer of humus. The richest soils of the islands are along drainage
areas and in alluvial deposits.
Coralline soils result from the decomposition of limestone, coral
fragments, shells, and sand, and are overlain by some humus. Where the
layer of humus is deep, the fertility is greatest. Coralline-volcanic
soils occur on some "high" islands where coral rock and volcanic rock
have become mixed in the decomposition process which forms soil. In
parts of the Marianas and elsewhere, unwise practices of burning and
overgrazing have allowed extensive erosion to occur, resulting in
reduced fertility of the soil. On the island of Yap certain sedimentary
rocks are exposed which are thought to have been elevated from the ocean
bottom. Soils at Yap which have developed from this rock are considered
more fertile than soils of coralline origin, although the fertility
there also is dependent on the depth of the layer of humus.
SURFACE WATER
There is little fresh water on the coral atolls, but brackish marshes
are present on some islands, and many of these marshes are used for the
cultivation of taro by the natives. Some volcanic islands, on the other
hand, possess small streams and fresh water lakes, producing suitable
habitat for certain rails, gallinules and ducks. On the "low" islands in
the Marshalls, natural surface pools are rare.
VEGETATION
The "high" islands of Micronesia support a heavy cover of vegetation.
Typically the lowlands and stream courses are covered with dense jungle
vegetation, and the slopes and higher hills are covered with grasses and
brush. The vegetation of the "low" coral atolls and islands is, by
comparison, much less dense. Many shorelines are covered with scant
grasses and shrubs and the interior in many places is dominated by
coconut, betel palms, breadfruit, papaya, and pandanus. References to
papers dealing with plants in the islands of the Pacific may be obtained
in Merrill (1945), who (1945:207) writes, "Botanically, the low islands
are very uninteresting and monotonous. The flora of one is usually quite
the same as that of another, although these islands and islets may be
separated by many hundred and in some cases several thousand miles. The
native vegetation may be scanty or reasonably well developed, depending
on the size of the island, the quality of its soil, and whether or not
it is permanently inhabitated." Of the vegetation on the "high" islands
of the Pacific area, Merrill (1945:209) comments that the vegetation "is
well developed, particularly within the forested areas, but for these
high islands within the Pacific basin as a whole, the number of endemic
genera is relatively small and most of them have definite relationships
with those of Malaysia." Concerning the "high" islands of Micronesia,
Merrill (1945:210) remarks that these islands are smaller and more
isolated than some of the others in Oceania and have fewer individual
species "as compared with what one finds on islands of a similar size
located within limits of the Malay Archipelago. Thus with all of the
islands under Japanese mandate, and including a number of high, but at
the same time relatively small islands, less than 1,300 different
species are known, of which 230 manifestly represent purposely or
accidentally introduced ones. This relatively small flora includes
representatives of approximately 620 genera in 192 families.... Specific
endemism is relatively high, for approximately 460 species are confined
to the islands within the area under consideration. The generic endemism
is very low; about seven endemic genera only are involved for the whole
group." The figures for endemism of plants are comparable to those for
birds. Of endemic birds there are 5 genera, 35 species, and 73
subspecies. The total number of species of birds known from Micronesia
is only 206 as compared with 1,300 plants. Yamada (1926:966) writes that
the number of species of plants that Micronesia has in common with Japan
may be due to the influence of the "Japan Stream."
Many land birds in Micronesia depend directly on the plant life for
food. Possibly the soil (including its mineral content), upon which the
plants themselves depend for development of fruits and other edible
parts, may offer a limiting factor to the distribution of birds in
Micronesia. Possibly the fruits and other edible parts of plants do not
provide the necessary amounts of proteins, carbohydrates, minerals,
vitamins, and other essential food items for species of plant-eating
birds, which have not become established in Micronesia. Possibly some
species of plant-eating birds have reached Micronesia but have failed to
establish themselves because of some dietary deficiency caused by
poverty of the soils on which the plants grow. If a comparison were made
of soils and of the food values of fruits of plants in both the islands
of Micronesia and similarly sized islands in the Malay region, a
difference might be revealed which would partly explain why some
plant-eating birds have not become established in Micronesia.
GAZETTEER OF ISLANDS OF MICRONESIA
In the following list the name in current usage for each island or
island group in Micronesia is followed by other names which have been
used. There is no attempt made to list the names of the small islands of
each atoll or those of the myriads of small islets that lie offshore
from the larger volcanic islands. Collections have not been made on most
of the smaller islands. For the few on which a species has been
collected, the islet is adequately described in the account of the
particular species concerned. The reader may refer to Brigham (1900) for
a listing of the islands of the Pacific Ocean. Most of the islands
included in the following list may be located on the map of Micronesia
as shown in figures 2, 3, 4, and 5. These listings follow in order of
arrangement those in the Civil Affairs Handbooks, published by the
United States Navy Department (1943, 1944a, 1944b, and 1944c).
MARIANA ISLANDS
The Mariana Islands (also called Ladrone, Marianne, Marian) consist
of 14 single islands and one group of three islands. The Marianas
are all "high" or volcanic islands. The islands, shown in figure 2,
are listed as follows:
_Agrihan_ (also called Agrigan, Arijan, Francisco Xavier, Granger,
Gregus, Grigan, San Francisco Javier).
_Agiguan_ (also called Agaigan, Agiigan, Agiguan, Agigwan,
Aguigan, Aguijan, Aguyan, Guigan, Saint Ange, Santa Angel).
_Alamagan_ (also called Almagan, Aramagan, Concepcion).
_Anatahan_ (also called Anatagen, Anatajen, Anataxan, San
Joaquin).
_Asuncion_ (also called Asonson, Assongsong, Assumption).
_Guam_ (also called Guaham, Guahan).
_Guguan_ (also called Guguwan, Guugwan, Piedras, San Felipe, St.
Philippe).
_Maug_ (also called Mang, Mangs, Mauga, Monjas, Mougu, Saint
Laurent, San Lorenzo, Tunas).
_Medinilla_ (also called Bade, Bird, Farallon de Medinilla,
Rocher).
_Pagan_ (also called Pagon, Paygan, St. Ignace, San Ignacio).
_Rota_ (also called Luta, St. Anne, Santa Ana, Sarpan, Satpana,
Suta, Zarpane).
_Saipan_ (also called (Saepan, St. Joseph, San José, Saypan,
Siepan, Serpan, Seypan).
_Sarigan_ (also called St. Charles, San Carlos, Sariguan,
Sarigwan).
_Tinian_ (also called Bona Vista, Buenavista, Temean, Tenian,
Tiniamou).
_Uracas_ (also called Guy Rock, Farallon de Pájaros, Pájaros,
Urakasu).
[Illustration: FIG. 2. The Mariana Islands.]
PALAU ISLANDS
[Illustration: FIG. 3. The Palau Islands.]
The Palau Islands (also called Arrecifos, Palaos, Paleu, Pally,
Paloc, Pannog, Parao, Pelew) consist of 8 large islands, 18 smaller
islands, and a large number of minute islets, all enclosed in a
single reef system. The northern islands (Babelthuap and Koror) are
of volcanic origin; the southern islands (Peleliu and others) are
of coralline formation. Angaur, to the south of Peleliu, may be
included with the Palau Archipelago. From the standpoint of the
avian zoogeography, the coral islands or atolls of Kayangel, Merir,
Pulo Anna, Sonsorol, and Tobi are also included. The principal
islands, shown in figure 3, are listed below:
_Arakabesan_ (also called Ngarekobasang).
_Aurapushekaru_ (also called Aburashokoru, Auluptagel, Oluksakel,
Oropu-shakaru).
_Babelthuap_ (also called Babeldzuap, Babel Taob, Babelthouap,
Baberthaob, Baberudaobu, Babldaob).
_Eil Malk_ (also called Amototi, Cogeal, Irakong, Makarakaru).
_Garakayo_
_Koror_ (also called Coror, Goreor, Kororu).
_Malakal_ (also called Amalakell, Malaccan, Marakaru, Nanalake).
_Ngabad_
_Ngesebus_ (also called Guadokusu).
_Peleliu_ (also called Pelelew, Periryu, Pililer, Peliliu, Uler).
_Urukthapel_ (also called Cape, Kuapasungasu, Ngurukdapel, Ulugeang,
Uruk-taaburu, Uruktapi).
Included with the Palau group because of proximity and relationships of
the avifauna are the following:
_Angaur_ (also called Angauru, Angyaur, Ngaur, Ngeour, N'Yaur).
_Kayangel_ (also called Kadjangle, Kajanguru, Kazyanguru, Kianguel,
Kreiangel, Moore, Ngajangel, Ngeiangel).
_Merir_ (also called Marir, Meliel, Meriel, Meriru, Pulo Marier, Warren
Hastings).
_Pulo Anna_ (also called Anna, Bul, Bur, Current, Paola, Pul, Puru,
Wull).
_Sonsorol_ (also called St. Andrew, San Andreas, Sonesor, Songosor,
Sonseron, Sonsol, Sonsoru, Tschontil).
_Tobi_ (also called Codopuei, Johnstone, Kadogubi, Lectobis, Lord North,
Nevil, Togobei, Tokobei).
CAROLINE ISLANDS
The Caroline Islands consist of 41 island clusters or isolated
islands (exclusive of submerged coral reefs). These are of coral
formation. They are atolls or single islands except for Yap, which
is of sedimentary rock, and Kusaie, Ponapé, and Truk, which are of
volcanic rock. The principal islands are shown in figure 4 and are
listed as follows:
_East Fayu_ (also called Fajo, Faliao, Lutké, Rukutee).
_Eauripik_ (also called Aurepik, Eourpyg, Iuripik, Kama, Low,
Yorupikku, Yuripik).
_Fais_ (also called Astrolabe, Feis, Feys, Fuhaesu, Huhaesu,
Tromelin, Woaje).
_Faraulep_ (also called Faraulip, Faroilap, Fattoilap, Foroilap,
Furaarappu, Gardner, Huraarappu).
_Ifalik_ (also called Evalook, Faloc, Furukku, Hurukku, Ifalouk,
Ifelug, Two Sisters, Wilson).
_Kapingamarangi_ (also called Bakiramarang, Constantine,
Greenwich, Guriinitchi, Kabeneylon, Kapenmailang, Makarama,
Pikiram, Tenuv).
_Kusaie_ (also called Arao, Armstrong, Experiment, Hope, Kusai,
Kuschai, Kushai, Kuthiu, Oualan, Quollen, Strong, Teyoa, Ualan,
Walang).
_Lamotrek_ (also called Lamorsu, Lamureck, Lamutrik, Low, Namotik,
Namotikku, Manochikku, Namurrek, Swede).
_Lukunor_ (also called Lemarafat, Lougoullos, Lougounor, Luganor,
Lugunor, Lugunoz, Mortlock, Namonefeng, Rukunoru, Youngwilliam).
_Namonuito_ (also called Anonyma, Baxos de San Bartolomeo, Bunkey,
Las Hermanas, Livingstone, Lost Jardines, Lutké, Namenwita, Olol,
Omun, Onon, Ororu, Remp, Ueito, Ulul).
_Ngulu_ (also called Angegul, Anolul, Goulou, Kurru, Lamoliao,
Lamoliork, Lamuliur, Lamuniur, Matelotas, Ngilu, Ngoli, Ngolog,
Spencer Keys, Ulu).
_Nukuoro_ (also called Dunkin, Matakema, Menteverde, Nugoru,
Nukor, Nukuor).
_Pikelot_ (also called Bigali, Biguela, Coquille, Lydia, Pigela,
Pigerotto, Pigouelao, Pik, Pyghella).
_Pingelap_ (also called Macaskill, Musgrave, Pelelap, Piigerappu,
Punlap, Sailrocks, Tucks Reef).
_Ponapé_ (also called Ascension, Bonabee, Bonybay, Faloupet,
Faounoupei, Funopet, Niponpei, Painipete, Ponapi, Piunipet,
Puynipet, Quirosa, Seniavin, William IV). Ponapé is the largest
island of the Senyavin Islands.
_Truk_ (also called Djuk, Hogoleu, Hogolu, Hoguleu, Lugulus, Ola,
Rough, Ruck, Ruk, Torakku, Tuck, Ugulut). The Truk group includes
approximately 100 islands.
_Ulithi_ (also called Mackenzie, Mogmog, Mogumogu, Mokomok,
Ouluthy, Uluthi, Uluti, Urushi).
_West Fayu_ (also called Faiyao, Fajahu, Faliau, Huiyao, West
Faiu).
_Woleai_ (also called Anagai, Mereyon, Oleai, Ouleyai, Thirteen
Islands, Uala, Ulea, Uola, Ulie, Wolea).
_Yap_ (also called Eap, Guap, Heap, Jap, Ouap, Uap, Wuap, Yappu).
[Illustration: FIG. 4. The Caroline Islands.]
MARSHALL ISLANDS
The Marshall Islands consist of 29 atolls and 5 coral islands
without lagoons arranged in two chains, the Ralik and the Radak
chains, which extend in a northwesterly to southeasterly direction.
No volcanic rocks are exposed in these islands. The principal
islands shown in figure 5 are as follows:
_Ailuk_ (also called Ailu, Fisher, Krusenstern, Tindall, Watts).
_Arhno_ (also called Arno, Aruno, Auru).
_Bikar_
_Bikini_
_Ebon_ (also called Boston Atoll).
_Elmore_ (also called Ailinglap, Ailinglapalap, Iringlob).
_Eniwetok_
_Jaluit_ (also called Bonham, Taluit).
_Kwajalein_
_Likieb_ (also called Likiep).
_Majuro_ (also called Arrowsmith, Mezyuro).
_Mejit_
_Maloelab_
_Mille_ (also called Mulgrave).
_Namorik_
_Namu_ (also called Musquillo, Namo).
_Rongelap_
_Wotje_ (also called Romanzov, Wotze, Wozzie).
[Illustration: FIG. 5. The Marshall Islands.]
ORNITHOLOGICAL EXPLORATION IN MICRONESIA
The Micronesian islands were first explored and colonized by a a people
who came from Malaysia. It is thought that these people spread into the
Palau, Caroline, Mariana, Marshall, and Gilbert islands as a single wave
of migration. Following this occupation, the people apparently underwent
a normal process of cultural evolution and differentiation. Remains of
stone walls, dikes, fences, pillars, graves, and other structures which
may be found today at various islands in Micronesia were constructed by
the ancestors of the islanders of the present day. It is thought by
archeologists that the Polynesians moved eastward into the Pacific
islands by way of Micronesia. The date of this wave of migration is
thought to have been approximately 1200 A. D. What kinds of birds may
have been exterminated by this earliest of human colonization cannot be
ascertained. Edible species, particularly megapodes, rails, and pigeons,
probably were eliminated or reduced in numbers, as is indicated by later
discussions.
The first Europeans to visit Micronesia, as far as the present writer
can ascertain, left no accounts of the birds significant for the study
here reported upon. Magellan, on his trip around the world, was the
leader of the first party of Europeans who touched at Guam; this was on
March 6, 1521. Rota, Agiguan, Saipan, and Tinian were also discovered by
this Portuguese sea captain in the service of the king of Spain. Eltano,
one of Magellan's lieutenants, revisited the Pacific and stopped at Rota
in 1524. After the voyage of Magellan, other seafarers, mostly in the
service of Spain, visited the Micronesian islands. The Caroline Islands
were apparently first observed by the Portuguese captain, Diego de
Rocha, in 1526. Loyasa and Saavdera, both Spaniards, visited the
Marshall Islands in 1526 and 1529, respectively.
One of the first travelers to record observations on the bird life was
Henry Wilson. Wilson was captain of the schooner "Antelope" which became
grounded on a reef in the Palau Islands in August, 1783. He lived with
the islanders while the ship was being repaired and kept a journal of
his observations (Wilson, 1788). Wilson also visited several other
islands in western Micronesia. Adelbert von Chamisso (1821), as
naturalist with the Russian expedition in the ship "Rurick," made
observations of the animal life in Micronesia in 1817 and 1818. Under
the command of Otto von Kotzebue, this Russian expedition made the first
detailed exploration of the Marshall Islands; visits were made also to
Guam and Rota and to Yap, Fais, Ulithi, Palau, and other island groups
in western Micronesia. Freycinet's famous expedition in the ships
"Uranie" and "Physicienne," visited Guam, Rota, and Tinian in 1819. Quoy
and Gaimard, the naturalists of the expedition, obtained birds, which
were among the first to be described from Micronesia. These two
naturalists revisited the Marianas in 1829 on board the ship
"Astrolabe." Scientific results of both of these expeditions (Quoy and
Gaimard, 1824-'26 and 1830-'35) include texts and plates dealing with
the birds obtained.
The French expedition in the corvette "La Coquille" visited Kusaie in
June, 1824. Lesson (1829) wrote the zoology of this trip. Kittlitz
(1836) of the expedition which sailed in the corvette "Le Seniavine"
commanded by Lutké obtained birds at Kusaie in December and January,
1827-'28, at Guam in March, 1828, and at Lukunor and other islands of
the Carolines. At Kusaie, Kittlitz found a rail (_Aphanolimnas monasa_)
and a starling (_Aplonis corvinus_) which have not been obtained since
his time. His specimens were deposited in St. Petersburg. He was one of
the most competent of the early naturalists; his writings contain
accounts of habits as well as descriptions and are accompanied by
colored plates. The expedition which sailed on the "Astrolabe" and the
"Zélée" in 1827-'40 under the command of Dumont d'Urville visited the
Caroline Islands. The naturalists, Hombron and Jacquinot, obtained birds
at Truk, including the interesting flycatcher, _Metabolus rugensis_,
which they described (1841). The "Novara," in the course of its voyage
around the world (1857-'59) visited the Caroline Islands in 1858. Birds
were recorded from Ponapé, Lukunor and other islands by Pelzeln in his
account of the birds of the expedition (1865).
In the years following the middle of the Nineteenth Century, Godeffroy
and Sons, of Hamburg, opened branches of its trading firm in Micronesia.
Representatives of the company including Heinsohn and Peters, who were
ship captains, obtained collections of birds at Palau and Yap. These
were deposited in the Godeffroy Museum at Hamburg and reported on by
Hartlaub and Finsch (Hartlaub, 1868; Hartlaub and Finsch, 1868a and
1872). Tetens became representative of Godeffroy and Sons at Yap in 1869
and obtained birds. Perhaps the most famous collector in this period was
Johann Kubary. He went to Ponapé at the age of nineteen and traveled in
Micronesia for many years for Godeffroy and Sons. He obtained birds at
many of the islands of the Carolines, spending fourteen months at Truk.
In 1873, one of his collections of some 200 birds was lost in a
shipwreck. Hartlaub and Finsch, (Hartlaub and Finsch, 1872; Finsch,
1876a) described much of his material; Nehrkorn (1879) reported on nests
and eggs which he obtained. Hartlaub and Finsch (1868b) also reported on
birds obtained at Palau by Doctor Semper, which were deposited in the
museum at Altona. Otto Finsch (1880b, 1880d, 1881b, 1881c) traveled in
Micronesia about 1880, observing birds in the eastern Carolines and in
the Marshalls.
One of the largest collections from Micronesia was made by Alfred Marche
in the Marianas. He arrived there on April 22, 1887, and stayed until
May, 1889. He obtained approximately 732 specimens of birds, nests, and
eggs at Guam, Rota, Tinian, Saipan, Pagan, and Alamagan, which were
deposited in the Paris Museum and reported on by Oustalet (1895-'96).
Shortly after Marche's visit, Japanese collectors in the hire of Alan
Owston, a professional collector of Yokahama, obtained birds in the
Marianas and at Truk in the years 1894-'97. These went to the Rothschild
collection at Tring and were reported on by Hartert in 1898 and 1900.
At the turn of the Twentieth Century, several ornithologists were
visiting Micronesia. Alvin Seale (1901) obtained a collection of birds
at Guam in the summer of 1900 which was deposited in the Bernice P.
Bishop Museum in Honolulu. The U. S. Fish Commission steamer "Albatross"
visited Micronesia from August, 1899, to March, 1900; birds obtained by
the expedition were reported on by Townsend and Wetmore (1919). Paul
Schnee (1901) spent approximately one year, 1899-1900, at Jaluit in the
Marshalls and obtained records of birds. In 1899, Brandeis, on board the
German ship "Kaiserland" visited many of the islands in the Marshalls
and recorded birds. William Safford (1905) resided at Guam in the early
part of this century and reported on the bird life in the course of his
studies of the botany and native life. Bartsch (Mearns, 1909) also
obtained a small collection of birds at Guam, this is in the United
States National Museum.
In the first World War when the Japanese gained a mandated control over
the islands of Micronesia, the Japanese ornithologists promptly visited
the area, obtained collections, and published works concerning the
birds. In 1922, Momiyama and Kuroda prepared a list of the birds of
Micronesia. The work was published under the auspices of the
Ornithological Society of Japan. Subsequent editions appeared in 1932
and 1942.
The Whitney South Sea Expedition of the American Museum of Natural
History visited Micronesia from October, 1930, to December, 1931, with
William F. Coultas as collector. Although experiencing some difficulty
and being restricted somewhat in his travels by the Japanese officials,
he managed to obtain collections at Ponapé (October 26, 1930, to January
1, 1931), Kusaie (January 15 to June 11, 1931), Guam (June 24 to August
30, 1931), Saipan and Tinian (September 1 to 26, 1931), and Palau
(October 2 to December, 1931). Many of the species which he obtained are
represented by large series of fine skins. Only part of his collections
have been reported on by Mayr and his associates.
Other than the work of Coultas and that of the Japanese, there was
little ornithological work done in the period between the two world
wars, probably, at least in part, because of the "iron curtain," which
Japan had thrown about her mandate. Bryan (1936) did visit Guam in the
middle 1930's and published an account of the birds in the newspaper,
Guam Recorder.
When the Micronesian islands were taken by the American forces in 1944,
personnel attached to various units made observations on the bird life.
The first reports, published or unpublished, were from the Marshalls,
which were taken at the beginning of the campaign. Gleise, Genelly,
Wallace, and others made contributions. In the Marianas considerably
more observing and collecting were done by service personnel including
Marshall, Stott, Borror, Strophlet, Buss, Watson, Arvey, Downs, and
others. Marshall (1949) obtained also a collection of birds in the
Palaus in 1945. The Laboratory of Mammalogy, United States Naval Medical
Research No. 2, to which I was attached, collected at Guam (January to
October, 1945), at Rota (October 17 to November 2, 1945), at Ulithi
(August 11 to 23, 1945), at Palau (August 24 to September 24, 1945), and
at Truk (November 24 to December 18, 1945). Following the end of the
war, Harvey I. Fisher visited Micronesia and obtained a collection of
birds at Yap, which is to be reported on in the near future. Larry P.
Richards obtained 33 birds at Ponapé and 4 at Truk in the period from
August 28, 1947, to February 10, 1948.
Descriptions of birds in Micronesia began with the naming of _Halcyon c.
cinnamomina_ in 1821; the most recent description is that of _Rhipidura
rufifrons mariae_ in 1946. In all, 131 descriptions have designated type
localities in Micronesia. Table 1 lists the dates (on the basis of
ten-year intervals) when names of birds (synonyms or otherwise) were
proposed. In the period from 1821 to 1860, twenty-five birds were made
known to science by the earliest workers, including Kittlitz, Lesson,
Bonaparte, and Pelzeln. In the period from 1861 to 1880, thirty-four
birds were newly named, mostly by Hartlaub and Finsch, from the
collections which the Godeffroy Museum obtained through the efforts of
Kubary, Tetens, Peters, and Heinsohn. Nineteen original descriptions
were published from 1881 to 1900, principally by Oustalet and Hartert,
who studied the material of Marche and Owston, respectively. From 1901
to 1910, only four birds were described, but from 1911 to 1940,
forty-seven descriptions were published, mostly by the Japanese
following World War I. From 1931 to 1940, the number of known birds was
increased by the efforts of Mayr, who studied the material of the
Whitney South Sea Expedition. From 1941 to date only two original
descriptions have appeared--only one was postwar. Except for possible
undescribed subspecies in the northern Marianas, I think that the heyday
of the taxonomist in ornithology in Micronesia is over. The field of
avian ecology in Micronesia has barely been scratched.
TABLE 1. COMPILATION OF THE DATES (ON THE BASIS OF TEN-YEAR INTERVALS)
WHEN ORIGINAL DESCRIPTIONS OF BIRDS OF MICRONESIA APPEARED.
============+==============+============+==============
| No. of | | No. of
YEARS | descriptions | YEARS | descriptions
------------+--------------+------------+--------------
1821-1830 | 8 | 1881-1890 | 9
1831-1840 | 8 | 1891-1900 | 10
1841-1850 | 4 | 1901-1910 | 4
1851-1860 | 5 | 1911-1920 | 10
1861-1870 | 11 | 1921-1930 | 15
1871-1880 | 23 | 1931-1940 | 22
| 1941-1949 | 2
------------+--------------+------------+--------------
CHECK-LIST OF THE BIRDS OF MICRONESIA
The 206 kinds of birds of 150 full species known to occur in Micronesia
belong to 91 genera of 37 families of 13 orders. In the following list,
nonresident birds are marked with an *; birds introduced by man are
marked with a [+].
Class AVES--birds
PAGE
Order PROCELLARIIFORMES--albatrosses, petrels, and allies
Family Diomedeidae--albatrosses
_Diomedia nigripes_ Audubon* Black-footed Albatross 63
Family Procellariidae--petrels and shearwaters
_Puffinus pacificus chlororhynchus_
Lesson Wedge-tailed Shearwater 64
_Puffinus pacificus cuneatus_ Salvin Wedge-tailed Shearwater 65
_Puffinus tenuirostris_ (Temminck)* Short tailed Shearwater 66
_Puffinus nativitatus_ Streets Christmas Shearwater 66
_Puffinus lherminieri dichrous_ Finsch
and Hartlaub Dusky Shearwater 66
_Pterodroma rostrata rostrata_ (Peale)* Tahiti Petrel 69
_Pterodroma hypoleuca hypoleuca_ Salvin Stout-billed Gadfly Petrel 70
Order PELECANIFORMES--tropic birds, boobies, cormorants, frigate
birds and allies
Family Phaëthontidae--tropic birds
_Phaëthon aethereus mesonauta_ Peters* Red-billed Tropic Bird 70
_Phaëthon rubricauda rothschildi_
(Mathews) Red-tailed Tropic Bird 71
_Phaëthon lepturus dorotheae_ Mathews White-tailed Tropic Bird 72
Family Sulidae--boobies and gannets
_Sula dactylatra personata_ Gould Masked Booby 75
_Sula sula rubripes_ Gould Red-footed Booby 75
_Sula leucogaster plotus_ (Forster) Brown Booby 76
Family Phalacrocoracidae--cormorants
_Phalacrocorax melanoleucus melanoleucus_
(Vieillot) Little Pied Cormorant 78
Family Fregatidae--frigate birds or man-o'-war birds
_Fregata minor minor_ (Gmelin)* Pacific Man-o'-War 79
_Fregata ariel ariel_ (Gray) Least Man-o'-War 80
Order CICONIIFORMES--herons, storks, and allies
Family Ardeidae--herons and bitterns
_Butorides striatus amurensis_ Schrenck* Amur Green Heron 81
_Bubulcus ibis coromandus_ (Boddaert)* Cattle Egret 82
_Egretta intermedia intermedia_
(Wagler)* Plumed Egret 82
_Demigretta sacra sacra_ (Gmelin) Reef Heron 84
_Nycticorax nycticorax nycticorax_
(Linnaeus)* Black-crowned Night Heron 87
_Nycticorax caledonicus pelewensis_
Mathew Rufous Night Heron 87
_Gorsachius goisagi_ (Temminck)* Japanese Bittern 89
_Gorsachius melanolophus melanolophus_
(Raffles)* Malay Bittern 90
_Ixobrychus sinensis_ (Gmelin) Chinese Least Bittern 93
_Ixobrychus eurhythmus_ (Swinhoe)* Shrenck's Least Bittern 93
_Dupetor flavicollis flavicollis_
(Latham)* Black Bittern 94
Order ANSERIFORMES--ducks, geese, swans, and allies
Family Anatidae--ducks, geese, and swans
_Anas oustaleti_ Salvadori Marianas Mallard 94
_Anas poecilorhyncha pelewensis_
Hartlaub and Finsch Australian Gray Duck 98
_Anas querquedula_ Linnaeus* Garganey Teal 100
_Anas crecca crecca_ Linnaeus* European Teal 100
_Anas crecca carolinensis_ Gmelin* Green-winged Teal 100
_Anas acuta acuta_ Linnaeus* Pintail 101
_Anas acuta tzitzihoa_ Vieillot* Pintail 101
_Anas penelope_ Linnaeus* Widgeon 102
_Anas clypeata_ Linnaeus* Shoveller 102
_Aythya fuligula_ (Linnaeus)* Tufted Duck 103
_Aythya valisineria_ (Wilson)* Canvas-back 103
Order FALCONIFORMES--vultures, hawks, falcons
Family Accipitridae--hawks, harriers, and allies
_Accipiter soloënsis_ (Horsfield)* Chinese Goshawk 104
_Accipiter virgatus gularis_ (Temminck
and Schlegel)* Asiatic Sparrow Hawk 104
_Pandion haliaetus melvillensis_
Mathews Osprey 105
Family Falconidae--falcons and caracaras
_Falco peregrinus japonensis_ Gmelin* Peregrine Falcon 105
Order GALLIFORMES--megapodes, pheasants, and allies
Family Megapodidae--megapodes
_Megapodius lapérouse senex_ Hartlaub Micronesian Megapode 106
_Megapodius lapérouse lapérouse_ Gaimard Micronesian Megapode 109
Family Phasianidae--quails, pheasants, and allies
_Coturnix chinensis lineata_
(Scopoli)[+] Painted Quail 113
_Gallus gallus_ (Linnaeus)[+] Red Jungle Fowl 114
_Phasianus colchicus_ Linnaeus[+] Ring-necked Pheasant 115
Order GRUIFORMES--cranes, rails, and allies
Family Rallidae--rails, gallinules, and coots
_Rallus philippensis pelewensis_ (Mayr) Banded Rail 116
_Rallus owstoni_ (Rothschild) Guam Rail 118
_Rallina fasciata_ (Raffles)* Malay Banded Crake 120
_Rallina eurizonoïdes eurizonoïdes_
(Lafresnaye)* Philippine Banded Crake 121
_Aphanolimnas monasa_ (Kittlitz) Kusaie Black Rail 121
_Poliolimnas cinereus micronesiae_
Hachisuka White-browed Rail 123
_Gallinula chloropus_ subsp. near
_orientalis_ Horsfield Gallinule 126
_Gallinula chloropus guami_ Hartert Gallinule 127
_Porphyrio porphyrio pelewensis_ Hartlaub
and Finsch Purple Swamphen 129
_Fulica atra atra_ Linnaeus* Common Coot 131
Order CHARADRIIFORMES--shorebirds, gulls, and auks
Family Charadriidae--plovers, turnstones, and allies
_Squatarola squatarola_ (Linnaeus)* Black-bellied Plover 131
_Pluvialis dominica fulva_ (Gmelin)* Pacific Golden Plover 132
_Charadrius hiaticula semipalmatus_
Bonaparte* Semipalmated Plover 134
_Charadrius dubius curonicus_ Gmelin* Ring-necked Plover 135
_Charadrius alexandrinus nihonensis_
Deignan* Kentish Plover 135
_Charadrius mongolus stegmanni_
Stresemann* Mongolian Dotteral 135
_Charadrius leschenaultii_ Lesson* Large Sand Dotteral 137
Family Scolopacidae--snipe, sandpipers, and allies
_Numenius phaeopus variegatus_
(Scopoli)* Whimbrel 137
_Numenius tahitiensis_ (Gmelin)* Bristle-thighed Curlew 139
_Numenius madagascariensis_ (Linnaeus)* Long-billed Curlew 140
_Limosa lapponica baueri_ Naumann* Pacific Godwit 140
_Tringa nebularia_ (Gunnerus)* Greenshawk 141
_Tringa melanoleuca_ (Gmelin)* Greater Yellow-legs 142
_Tringa glareola_ Linnaeus* Wood Sandpiper 142
_Actitus hypoleucos_ Linnaeus* Common Sandpiper 143
_Heteroscelus brevipes_ (Vieillot)* Gray-tailed Tattler 144
_Heteroscelus incanus_ (Gmelin)* Amer. Wandering Tattler 145
_Arenaria interpres interpres_ (Linnaeus)* Turnstone 147
_Gallinago megala_ Swinhoe* Marsh Snipe 149
_Gallinago gallinago gallinago_ (Linnaeus)* Common Snipe 150
_Crocethia alba_ (Pallas)* Sanderling 150
_Calidris tenuirostris_ (Horsfield)* Asiatic Knot 151
_Erolia minuta ruficollis_ (Pallas)* Little Stint 151
_Erolia subminuta_ (Middendorff)* Least Sandpiper 152
_Erolia melanotos_ (Vieillot)* Pectoral Sandpiper 152
_Erolia acuminata_ (Horsfield)* Sharp-tailed Sandpiper 152
_Erolia ferruginea_ (Pontoppidan)* Curlew Sandpiper 153
_Limicola falcinellus sibirica_ Dresser* Broad-billed Sandpiper 154
Family Phalaropidae--phalaropes
_Phalaropus lobatus_ (Linnaeus)* Northern Phalarope 154
Family Laridae--gulls and terns
_Larus argentatus vegae_ Palmén* Herring Gull 154
_Chlidonias leucopterus_ (Temminck)* White-winged Black
Tern 155
_Sterna hirundo longipennis_ Nordmann* Black-billed Com. Tern 155
_Sterna sumatrana sumatrana_ Raffles Black-naped Tern 156
_Sterna lunata_ Peale Spectacled Tern 160
_Sterna anaetheta anaetheta_ Scopoli Bridled Tern 160
_Sterna fuscata oahuensis_ Bloxham Sooty Tern 161
_Sterna albifrons sinensis_ Gmelin* Least Tern 161
_Thalasseus bergii pelecanoides_ (King) Crested Tern 162
_Procelsterna cerulea saxatilis_
W. E. Fisher* Blue-gray Tern 164
_Anoüs stolidus pileatus_ (Scopoli) Common Noddy 165
_Anoüs tenuirostris marcusi_ (Bryan) White-capped Noddy 170
_Gygis alba candida_ (Gmelin) White Tern 174
_Gygis alba pacifica_ (Lesson) White Tern 180
Order COLUMBIFORMES--pigeons, doves, and allies
Family Columbidae--pigeons and doves
_Columba livia_ Gmelin[+] Blue Rock Pigeon 182
_Ptilinopus porphyraceus ponapensis_
(Finsch) Crimson-crw'd Fruit
Dove 182
_Ptilinopus porphyraceus hernsheimi_
(Finsch) Crimson-crw'd Fruit
Dove 184
_Ptilinopus porphyraceus pelewensis_
Hartlaub and Finsch Crimson-crw'd Fruit
Dove 185
_Ptilinopus roseicapillus_ (Lesson) Marianas Fruit Dove 186
_Ducula oceanica monacha_ (Momiyama) Micronesian Pigeon 190
_Ducula oceanica teraokai_ (Momiyama) Micronesian Pigeon 193
_Ducula oceanica townsendi_ (Wetmore) Micronesian Pigeon 194
_Ducula oceanica oceanica_ (Lesson and
Garnot) Micronesian Pigeon 195
_Ducula oceanica ratakensis_ (Takatsukasa
and Yamashina) Micronesian Pigeon 197
_Streptopelia bitorquata dusumieri_
(Temminck)[+] Philippine Turtle
Dove 198
_Gallicolumba canifrons_ (Hartlaub and
Finsch) Palau Ground Dove 201
_Gallicolumba xanthonura xanthonura_
(Temminck) White-thrt'd Ground
Dove 203
_Gallicolumba xanthonura kubaryi_ (Finsch) White-thrt'd Ground
Dove 207
_Caloenas nicobarica pelewensis_ Finsch Nicobar Pigeon 209
Order PSITTACIFORMES--lories and parrots
Family Psittacidae--lories, parrots, and allies
_Trichoglossus rubiginosus_ (Bonaparte) Ponapé Lory 211
Order CUCULIFORMES--cuckoos, plantain-eaters
Family Cuculidae--cuckoos, anis, and allies
_Cuculus canorus telephonus_ Heine* Common Cuckoo 213
_Cuculus saturatus horsfieldi_ Moore* Oriental Cuckoo 214
_Eudynamis taitensis_ (Sparrman)* Long-tailed New
Zealand Cuckoo 214
Order STRIGIFORMES--owls
Family Strigidae--owls
_Otus podarginus_ (Hartlaub and Finsch) Palau Scops Owl 215
_Asio flammeus flammeus_ (Pontoppidan)* Short-eared Owl 217
_Asio flammeus ponapensis_ Mayr Short-eared Owl 218
Order CAPRIMULGIFORMES--goatsuckers and allies
Family Caprimulgidae--goatsuckers
_Caprimulgus indicus jotaka_ Temminck
and Schlegel* Jungle Nightjar 219
_Caprimulgus indicus phalaena_ Hartlaub
and Finsch Jungle Nightjar 219
Order APODIFORMES--swifts and hummingbirds
Family Apodidae--swifts
_Collocalia inexpectata pelewensis_ Mayr Edible Nest Swiftlet 221
_Collocalia inexpectata bartschi_ Mearns Edible Nest Swiftlet 222
_Collocalia inquieta inquieta_ (Kittlitz) Carolines Swiftlet 224
_Collocalia inquieta rukensis_ Kuroda Carolines Swiftlet 225
_Collocalia inquieta ponapensis_ Mayr Carolines Swiftlet 226
Order CORACIIFORMES--kingfishers, rollers, and allies
Family Alcedinidae--kingfishers
_Halcyon cinnamomina cinnamomina_ Swainson Micronesian
Kingfisher 227
_Halcyon cinnamomina pelewensis_ Wiglesworth Micronesian
Kingfisher 229
_Halcyon cinnamomina reichenbachii_
(Hartlaub) Micronesian
Kingfisher 230
_Halcyon chloris teraokai_ Kuroda White-collared
Kingfisher 233
_Halcyon chloris orii_ Takatsukasa and
Yamashina White-collared
Kingfisher 235
_Halcyon chloris albicilla_ (Dumont) White-collared
Kingfisher 235
_Halcyon chloris owstoni_ Rothschild White-collared
Kingfisher 237
Family Coraciidae--rollers
_Eurystomus orientalis connectens_
Stresemann* Dollar Bird 238
Order PASSERIFORMES--perching birds
Family Hirundinidae--swallows
_Hirundo rustica gutteralis_ Scopoli* Eastern Barn Swallow 239
Family Campephagidae--cuckoo-shrikes
_Edolisoma tenuirostre monachum_
(Hartlaub and Finsch) Cicada Bird 239
_Edolisoma tenuirostre nesiotis_
(Hartlaub and Finsch) Cicada Bird 241
_Edolisoma tenuirostre insperatum_ (Finch) Cicada Bird 242
Family Dicruridae--drongos
_Dicrurus macrocercus harterti_ S. Baker[+] Black Drongo 244
Family Corvidae--crows, magpies, and jays
_Corvus kubaryi_ Reichenow Marianas Crow 244
Family Turdidae--thrushes
_Luscinia calliope calliope_ (Pallas)* Siberian Rubythroat 248
_Monticola solitaria philippensis_ (Müller)* Chinese Blue Rock
Thrush 248
_Turdus obscurus obscurus_ Gmelin* Dusky Thrush 248
Family Sylviidae--Old World warblers
_Psamathia annae_ Hartlaub and Finsch Palau Bush-warbler 249
_Acrocephalus luscinia luscinia_ (Quoy and
Gaimard) Nightingale
Reed-warbler 251
_Acrocephalus luscinia syrinx_ (Kittlitz) Nightingale
Reed-warbler 254
_Acrocephalus luscinia yamashinae_
(Takatsukasa) Nightingale
Reed-warbler 256
_Acrocephalus luscinia nijoi_ (Yamashina) Nightingale
Reed-warbler 257
Family Muscicapidae--Old World flycatchers
_Rhipidura rufifrons uraniae_ Oustalet Rufous-fronted
Fantail 261
_Rhipidura rufifrons saipanensis_ Hartert Rufous-fronted
Fantail 262
_Rhipidura rufifrons mariae_ R. H. Baker Rufous-fronted
Fantail 263
_Rhipidura rufifrons versicolor_ Hartlaub
and Finsch Rufous-fronted
Fantail 264
_Rhipidura rufifrons kubaryi_ Finsch Rufous-fronted
Fantail 265
_Rhipidura lepida_ Hartlaub and Finsch Palau Fantail 266
_Metabolus rugensis_ (Hombron and Jacquinot) Truk Monarch 269
_Monarcha godeffroyi_ Hartlaub Yap Monarch 272
_Monarcha takatsukasae_ (Yamashina) Tinian Monarch 274
_Myiagra oceanica erythrops_ Hartlaub and
Finch Micronesian Broadbill 275
_Myiagra oceanica freycineti_ Oustalet Micronesian Broadbill 277
_Myiagra oceanica oceanica_ Pucheran Micronesian Broadbill 279
_Myiagra oceanica pluto_ Finsch Micronesian Broadbill 280
_Muscicapa narcissina narcissina_ Temminck* Narcissus Flycatcher 282
_Muscicapa griseisticta_ (Swinhoe)* Chinese Gray-spotted
Flycatcher 282
_Colluricincla tenebrosa_ (Hartlaub and
Finsch) Palau Morning Bird 282
Family Artamidae--wood-swallows
_Artamus leucorhynchus pelewensis_ Finsch White-breasted
Wood-swallow 284
Family Sturnidae--starlings
_Aplonis opacus opacus_ (Kittlitz) Micronesian Starling 286
_Aplonis opacus ponapensis_ Takatsukasa and
Yamashina Micronesian Starling 288
_Aplonis opacus angus_ Momiyama Micronesian Starling 289
_Aplonis opacus kurodai_ Momiyama Micronesian Starling 291
_Aplonis opacus orii_ (Takatsukasa and
Yamashina) Micronesian Starling 292
_Aplonis opacus guami_ Momiyama Micronesian Starling 293
_Aplonis opacus aeneus_ (Takatsukasa and
Yamashina) Micronesian Starling 297
_Aplonis pelzelni_ Finsch Ponapé Mountain
Starling 299
_Aplonis corvinus_ (Kittlitz) Kusaie Mountain
Starling 301
_Sturnus philippensis_ (Forster)* Violet-backed
Starling 302
_Sturnus cineraceus_ Temminck* Ashy Starling 302
Family Meliphagidae--honey-eaters
_Cleptornis marchei_ (Oustalet) Golden Honey-eater 302
_Myzomela cardinalis rubratra_ (Lesson) Cardinal Honey-eater 304
_Myzomela cardinalis dichromata_ Wetmore Cardinal Honey-eater 307
_Myzomela cardinalis major_ Bonaparte Cardinal Honey-eater 307
_Myzomela cardinalis saffordi_ Wetmore Cardinal Honey-eater 309
_Myzomela cardinalis kurodai_ Momiyama Cardinal Honey-eater 312
_Myzomela cardinalis kobayashii_ Momiyama Cardinal Honey-eater 313
Family Zosteropidae--white-eyes
_Zosterops conspicillata conspicillata_
(Kittlitz) Bridled White-eye 316
_Zosterops conspicillata saypani_ Dubois Bridled White-eye 318
_Zosterops conspicillata rotensis_
Takatsukasa and Yamashina Bridled White-eye 319
_Zosterops conspicillata semperi_ Hartlaub Bridled White-eye 320
_Zosterops conspicillata owstoni_ Hartert Bridled White-eye 321
_Zosterops conspicillata takatsukasai_
Momiyama Bridled White-eye 322
_Zosterops conspicillata hypolais_
Hartlaub and Finsch Bridled White-eye 323
_Zosterops cinerea cinerea_ (Kittlitz) Micron. Dusky
White-eye 326
_Zosterops cinerea ponapensis_ Finsch Micron. Dusky
White-eye 327
_Zosterops cinerea finschii_ (Hartlaub) Micron. Dusky
White-eye 328
_Rukia palauensis_ (Reichenow) Palau Greater
White-eye 330
_Rukia oleaginea_ (Hartlaub and Finsch) Yap Greater
White-eye 331
_Rukia ruki_ (Hartert) Truk Greater
White-eye 332
_Rukia sanfordi_ (Mayr) Ponapé Greater
White-eye 333
Family Ploceidae--weaver-finches
_Erythrura trichroa trichroa_ (Kittlitz) Blue-faced
Parrot-finch 336
_Erythrura trichroa clara_ Takatsukasa
and Yamashina Blue-faced
Parrot-finch 337
_Erythrura trichroa pelewensis_ Kuroda Blue-faced
Parrot-finch 338
_Lonchura nigerrima minor_ (Yamashina) Black-faced
Weaver-finch 339
_Lonchura punctulata cabanisi_ (Sharpe)[+] Phil. Nutmeg
Mannikin 340
DISCUSSION OF THE BIRDS OF MICRONESIA
Of the 206 kinds of birds found in Micronesia, 30 kinds are classed as
sea birds, 29 kinds as migratory shore birds, and 147 kinds are classed
as land and fresh-water birds. For purposes of discussion these birds
are arranged in these three categories, following the system used by
Mayr (1945a).
OCEANIC BIRDS
Oceanic birds found in Micronesia belong to the following families:
Diomedeidae, Procellariidae, Phaëthontidae, Pelecanidae, Fregatidae,
and Laridae. Following Wynne-Edwards (1935:240) and Murphy (1936:326),
these birds may be grouped as inshore birds (Laridae and others),
offshore birds (Pelecanidae, Fregatidae and others), and pelagic birds
(Diomedeidae, Procellariidae, Phaëthontidae). As shown in table 2 there
are 30 kinds of oceanic birds in Micronesia, 18 kinds that are resident
and 12 kinds that are regarded as visitors to the area. Records of
nestings are few; field work in the future probably will yield evidence
that more kinds of oceanic birds are actually resident in the
Micronesian islands.
TABLE 2. LIST OF RESIDENT AND NONRESIDENT OCEANIC BIRDS OF MICRONESIA
-------------------+----------+-------------
Genera | Resident | Nonresident
| kinds | kinds
-------------------+----------+-------------
_Diomedea_ | 0 | 1
_Puffinus_ | 4 | 1
_Pterodroma_ | 1 | 1
_Phaëthon_ | 2 | 1
_Sula_ | 3 | 0
_Fregata_ | 1 | 1
_Larus_ | 0 | 1
_Chlidonias_ | 0 | 1
_Sterna_ | 2 | 4
_Thalasseus_ | 1 | 0
_Procelsterna_ | 0 | 1
_Anoüs_ | 2 | 0
_Gygis_ | 2 | 0
-------------------+----------+-------------
INSHORE OCEANIC BIRDS
The inshore zone, according to Wynne-Edwards (1935:240), "extends from
high-water mark to a maximum of four or five miles out to sea, including
islands and reefs within sight of shore." In Micronesia the majority of
the Laridae occur in this zone including such residents as _Sterna
sumatrana_, _S. anaetheta_, _Thalasseus bergii_, _Anoüs stolidus_, _A.
tenuirostris_, _Gygis alba_. These birds, especially _S. anaetheta_,
_Thalasseus_, and _Anoüs_, may venture into the offshore zone. Visitors
to Micronesia include several terns which probably normally range in
the inshore (as well as in offshore) zones, such as _Childonias
leucopterus_ and _Sterna hirundo_. These birds feed to a considerable
extent inside the outer reefs surrounding the lagoons, coming to shore
frequently in small or large groups. _Gygis alba_ probably spends
considerable time on shore; stomachs examined contained fish,
crustaceans and insects, indicating that they obtain some of their food
ashore.
OFFSHORE AND PELAGIC OCEANIC BIRDS
Wynne-Edwards (1935:241) defines the offshore zone as extending to the
continental edge; however, in Micronesia where small islands rise
abruptly out of the ocean's depths, there is no useful way to separate
the offshore zone from the pelagic zone. Since certain species go
farther from the land than others, the two zones may be combined as a
single zone extending beyond the sight of land. Birds which frequent
this area beyond the inshore zone but may not range extensively at sea
include _Fregata_, _Sula_, _Sterna fuscata_, _S. hirundo_, _S.
anaetheta_, and others. The Herring Gull (_Larus argentatus_), which has
been taken in the northern Marianas, may be classed with this group
although it probably ranges widely in the open sea. Birds which spend
considerable time at sea and may seldom approach land include _Diomedea
nigripes_, the petrels (_Puffinus_ and _Pterodroma_), and possibly the
tropic birds (_Phaëthon_).
In numbers of individuals the birds inhabiting the inshore zones are
relatively more numerous than those preferring the offshore and pelagic
zones, although 12 of the 18 resident kinds of oceanic birds apparently
prefer the offshore zone, while only 6 kinds appear to be restricted
primarily to the inshore areas.
FAUNAL COMPONENTS
The oceanic birds were probably among the earliest birds to reach the
islands of Micronesia. The presence of phosphate deposits on islands
(Fais, Angaur), denoting deposition of guano by oceanic birds (possibly
boobies, noddies, sooty terns), indicates long time residence by these
birds. A person is prone to think that these deposits must have been
made by larger concentrations of oceanic birds than are found in these
islands today. Whether there were actually more individuals present
during the period of deposition of phosphate in the lagoons of these
islands is not known, although the elevation of the lagoons (forming the
raised islands of Fais and Angaur) with the resulting freshening of the
water probably was a great attraction to oceanic birds, especially to
those which prefer to drink fresh water. According to Leonard P. Schultz
(_in litt._), the abundance of fish in the areas about these Pacific
islands has been approximately the same since Pleistocene times, so that
there was apparently no greater concentration of fish near these islands
to attract large populations of fish-eating sea birds. Probably the time
element is of sufficient magnitude to account for such deposition by
birds with a population similar to that found there today.
The oceanic avifauna of Micronesia contains birds which are apparently
from ancestral homes in the Palearctic Region, in the North and Central
Pacific, in Polynesia, in Melanesia and Malaysia, and from homes the
positions of which are uncertain because of the widespread
circumtropical occurrence of the birds. There are no sea birds that are
endemic in Micronesia.
Oceanic birds whose range is in the Northern Hemisphere (especially
Palearctica) reach the northern and western edges of Micronesia as
winter visitors. These include _Larus argentatus_, _Chlidonias
leucopterus_, and _Sterna hirundo_. Another northern gull, _Larus
ridibundus_, has been reported in the Marianas.
One bird of the North and Northcentral Pacific, _Diomedea nigripes_,
reaches the northern Marianas where it has been taken at Agrihan. It is
not unlikely that other birds of the North Pacific reach northern
Micronesia as occasional visitors.
Species of oceanic birds which are restricted in their distribution to
Polynesia and some adjacent islands and which range to Micronesia,
either as visitors or residents, include _Puffinus tenuirostris_, _P.
nativitatis_, _Pterodroma rostrata_, _P. hypoleuca_, _Sterna lunata_,
and _Procelsterna cerulea_. The islands of the vast Pacific basin offer
havens for many kinds of oceanic birds. Apparently there has been
considerable speciation among sea birds in Polynesia, especially in its
marginal areas. Micronesia has received only a small part of this
avifauna.
Two terns, _Sterna sumatrana_ and _Thalasseus bergii_, have reached
Micronesia, either directly or indirectly, each from a dispersion point
somewhere in the Melanesian or the Malayan area. These two birds are
restricted in their ranges to the western Pacific and the Indian oceans.
Many of the species of oceanic birds found in Micronesia have
circumtropical ranges. These include _Puffinus pacificus_, _P.
lherminieri_, _Phaëthon_, _Sula_, _Fregata_, _Sterna anaethetus_, _S.
fuscata_, _Anoüs stolidus_, _A. tenuirostris_, and _Gygis alba_. Some of
these kinds range along continental shores as well as in island
archipelagoes. Others, like _Gygis alba_, are rarely found along the
shores of continents or even at coastal islands.
MIGRATORY SHORE BIRDS
Twenty-eight species of shore birds of the families Charadriidae and
Scolopacidae have been recorded from Micronesia, and one other of the
family Phalaropodidae apparently occurs in the area, making a total of
29 kinds. From the entire Southwest Pacific, Mayr (1945a:28-47) lists 31
species and subspecies of shore birds and mentions six other species
which may occur there. Thus, of a possible 37 kinds of shore birds in
this large area (which includes Micronesia), 29 are present in the
islands of Micronesia. For purposes of discussion, shore birds are here
placed in one of two groups: regular visitors or uncommon visitors. A
regular visitor is one which has been recorded in the literature or in
unpublished field accounts as being frequently observed in Micronesia in
periods of migration. An uncommon visitor is one which has been
infrequently observed in Micronesia. Of the 28 kinds of shore birds
recorded from Micronesia, 17 are classed as regular visitors and 11 are
classed as uncommon visitors.
ORIGINAL HOMES OF THE SHORE BIRDS THAT VISIT MICRONESIA
TABLE 3. BREEDING AND WINTERING GROUNDS OF THE SPECIES OF MIGRATORY
SHORE BIRDS IN MICRONESIA
PART A. Location of breeding grounds
==================+========+================+=========+==========
CLASS | Number | Circumpolar[A] | Asiatic | American
------------------+--------+----------------+---------+----------
Regular visitors | 17 | 5 | 10 | 2
Uncommon visitors | 11 | 2 | 8 | 1
+--------+----------------+---------+----------
Totals | 28 | 7 | 18 | 3
------------------+--------+----------------+---------+----------
PART B. Location of wintering grounds
------------------+--------+---------+---------+----------+---------
CLASS | Number | Circum- | Asiatic | American | Oceanic
|tropical| | | |
------------------+--------+---------+---------+----------+---------
Regular visitors | 17 | 2 | 13 | 1 | 1
Uncommon visitors | 11 | 1 | 8 | 2 | 0
+--------+---------+---------+----------+---------
Totals | 28 | 3 | 21 | 3 | 1
------------------+--------+---------+---------+----------+---------
[A] Denotes birds which breed on both American and Asiatic sides of the
Pacific Ocean.
The shore birds which are known to visit Micronesia breed in the
Northern Hemisphere. Table 3 summarizes the data concerning the
breeding and wintering areas of these birds. As shown in part A of table
3, 18 of the 28 species which visit Micronesia come from Asiatic
breeding grounds. Seven have circumpolar breeding ranges and three (two
are regular visitors) come from American breeding grounds. As shown in
part B of table 3, 21 of the 28 waders have their winter ranges on the
Asiatic side of the Pacific with eastern extensions to Micronesia and
other parts of Oceania. Of the 7 remaining species, the winter ranges of
three are circumtropical; the winter range of a fourth is restricted to
Oceania; and the winter ranges of the remaining three (two classed as
uncommon visitors) are American.
Bryan and Greenway (1944:109-115) record 14 species of shore birds from
the Hawaiian Islands. One of these, _Himantopus himantopus knudsoni_, is
a resident, probably of New World origin, according to Mayr (1943:56).
The others, listed in table 7, include three species unknown in
Micronesia. One of these, _Phalaropus fulicarus_, apparently winters at
sea off the west coast of South America. The other two species
(_Charadrius vociferus vociferus_ and _Gallinago delicata_) are
classified by Bryan and Greenway as "accidental" and "occasional"
visitors from North America. The ten species common to both the Hawaiian
Islands and Micronesia include seven whose breeding grounds are
circumpolar, two whose breeding grounds are in Arctic America and one
whose breeding ground is in Arctic Asia. The winter ranges of these ten
species include four which are circumtropical, three which are Asiatic,
one which is restricted to Oceania, and only two which are American.
The ability of the shore birds to migrate almost as well over water as
over land may explain their spread into Oceania. The likelihood that
shore birds, when migrating may have ventured to Micronesia and
Polynesia initially from the Asiatic side of the Pacific is strongly
suggested by the data given in the paragraph above. Also, on the Asiatic
side of the Pacific there are large numbers of islands, which form
several archipelagoes extending from Kamchatka south to Malaysia. Once
accustomed to migrating along these chains of islands from the Arctic to
Australia, birds would probably have to make only minor adjustments to
extend the breadth of their migratory routes eastward into the islands
of the Pacific Ocean. In contrast, on the Pacific coast of North America
there are few coastal or offshore islands and there is a vast area of
open water separating the Hawaiian Islands from the American mainland.
Probably the vastness of this area of water offers little stimulus to
birds to expand their migratory ranges westward, and in part accounts
for the small North American contingent in the population of shore birds
of the Central Pacific. Some North American shore birds do visit the
Pacific. The brisk trade winds from the northeast might be an aid to the
birds in their flights from Nearctica to Hawaii.
The long flight now made by shore birds going from the Aleutians to the
Hawaiian Islands may have commenced as a gradual expansion from the
west, or perhaps such a route was initiated by birds flying northward
through the Hawaiian Chain to the Arctic in migrating to their breeding
grounds, and then later returning _via_ the same route to reach their
wintering grounds.
ROUTES OF MIGRATION
[Illustration: FIG. 6. Routes of migration used by shore birds in the
Pacific area. From west to east these are: The Asiatic-Palauan Flyway,
the Japanese-Marianan Flyway, the Nearctic-Hawaiian Flyway.]
The small and isolated islands of Oceania might, upon first inspection,
seem to offer but little attraction to shore birds. Hesse, Allee and
Schmidt (1937:172, 173) point out that the "open southeastern Pacific"
being least supplied with water from land sources, which is an important
means of fertility, is known to have one of the poorest faunas found
anywhere in the oceans. However, there are extensive tidal flats,
especially on the leeward sides of the islands, and these flats
apparently afford extensive feeding grounds for these birds. Also, the
absence of competition from resident birds as well as the virtual
absence of predatory animals (native man and his domesticated animals
excepted) are other factors which may help to make the islands
attractive wintering grounds for shore birds.
Only a few birds have been banded in the Pacific, and the knowledge
which comes from the recovery of banded birds gives but little aid to
the student of movements of birds in the Pacific. The probable flyways
for migratory shore birds there have to be deduced from sight records,
data from specimens collected, known stations of breeding and wintering
(summarized by Peters, 1934:234-293), and from a study of maps of the
region. Analysis of information from the above-mentioned sources
indicates that there are three routes taken by shore birds which migrate
from Micronesia to and from their northern breeding grounds (see figure
6): (1) Asiatic-Palauan Flyway; (2) Japanese-Marianan Flyway; (3)
Nearctic-Hawaiian Flyway.
1. ASIATIC-PALAUAN FLYWAY. For shore birds, there appears to be a
migration route extending almost due south from the Riu Kiu and the
Japanese islands to the Palau Islands. Some birds may migrate _via_ the
Philippines and others may pass to the east of the Philippines. This
route is considered to be distinct from that used by birds which follow
the Asiatic Coast and coastal islands, because the Palau Islands are
situated approximately 600 miles east of the Philippines. Moreover,
there are fewer species--only 20 recorded from the Palaus as compared
with the number recorded from islands closer to the mainland of Asia.
Delacour and Mayr (1946:68-74) list 46 species of shore birds from the
Philippines; the Hand-list of Japanese Birds (Hachisuka _et al_, 1942)
lists 34 species from the Riu Kiu Islands.
The information available indicates that migrant shore birds which
utilize this flyway move east into the Carolines (examples, _Tringa
nebularia_, _Charadrius leschenaultii_); however, the recording of 20
species from the Palaus as compared with only 12 species in the western
Carolines (table 4) indicates that this spread eastward may not be very
pronounced. Migrants in autumn probably move from the Palaus in a
southerly direction toward the New Guinea area. Eight species of shore
birds which reach the Palaus (and adjacent islands in the western
Carolines), are not recorded from other parts of Micronesia. Species
which apparently utilize the Asiatic-Palauan Flyway are listed in table
5.
2. JAPANESE-MARIANAN FLYWAY. Shore birds from Asiatic, and probably
Aleutian and Alaskan, breeding grounds may follow the Asiatic Coast or
the adjacent island chains southeast to the Japanese Archipelago. From
there some of the birds apparently fly south through the Bonin and
Volcano islands to the Marianas, from where they may spread in fanlike
fashion to the southeast, south and southwest, even reaching to the
Palau Islands (example, _Heteroscelus incanus_). The number of species
of shore birds recorded from the Marianas (see table 4) is greater than
that found in the Carolines, but it must be remembered that more
intensive investigations have been made by ornithologists in the
Marianas, which might account for the recording of more species
(especially stragglers, such as _Gallinago gallinago_). Species which
apparently use this flyway are named in table 6.
3. NEARCTIC-HAWAIIAN FLYWAY. Shore birds from breeding grounds in
western Canada, Alaska, the Aleutians, the Bering Sea area, and probably
northeastern Asia may fly in a southerly direction along a broad front
to the Hawaiian Islands. This flyway is probably the one which supplies
to central and eastern Oceania the largest wintering populations of
shore birds. From the Hawaiian Islands birds may fly directly south
through the scattered islands to southern Polynesia, or they may fly in
a southwesterly direction and reach the Marshall Islands. The shore
birds which visit the Marshall Islands apparently move south through the
Gilbert, Ellice and other more southern island groups rather than west
into the Carolines as exemplified by the fact that _Numenius
tahitiensis_, a characteristic migrant through the Marshalls from the
Hawaiian Islands, is rarely found west of the Marshall Islands in
Micronesia. Species which apparently use this flyway are listed in table
7.
Flyways additional to the three suggested above may be utilized by some
shore birds on their southward (and northward) migrations. Species
reaching Wake and the Marcus Islands may fly directly south from the
islands of the North Pacific. Bryan (1903:115, 116) lists four species
of shore birds from Marcus (_Erolia acuminata_, _Heteroscelus incanus_,
_Pluvialis dominica_, _Arenaria interpres_).
TABLE 4. LIST OF SPECIES OF SHORE BIRDS KNOWN FROM FIVE GEOGRAPHICAL
AREAS OF MICRONESIA
Western Central Eastern
Palaus Carolines Marianas Carolines Carolines Marshalls
Number of species 20 12 17 11 10 10
TABLE 5. SHORE BIRDS WHICH MAY USE THE ASIATIC-PALAUAN FLYWAY
Regular Visitors Uncommon? Visitors
_Pluvialis dominica fulva_ _Charadrius dubius curonicus_
_Charadrius mongolus stegmanni_ _Charadrius alexandrinus_
_Charadrius leschenaultii_ _Calidris tenuirostris_
_Numenius phaeopus variegatus_ _Erolia ferruginea_
_Numenius madagascariensis_ _Erolia subminuta_
_Limosa lapponica baueri_ _Limicola falcinellus sibirica_
_Tringa nebularia_
_Tringa glareola_
_Actitis hypoleucos_
_Heteroscelus brevipes_
_Arenaria i. interpres_
_Gallinago megala_
_Erolia minuta ruficollis_
TABLE 6. SHORE BIRDS WHICH MAY USE THE JAPANESE-MARIANAN FLYWAY
Regular Visitors Uncommon? Visitors
_Pluvialis dominica fulva_ _Squatarola squatarola_
_Charadrius mongolus stegmanni_ _Numenius tahitiensis_
_Numenius phaeopus variegatus_ _Numenius madagascariensis_
_Limosa lapponica baueri_ _Tringa glareola_
_Actitis hypoleucos_ _Gallinago gallinago gallinago_
_Heteroscelus brevipes_ _Erolia minuta ruficollis_
_Heteroscelus incanus_
_Arenaria i. interpres_
_Gallinago megala_
_Crocethia alba_
_Erolia acuminata_
TABLE 7. SHORE BIRDS WHICH MAY USE THE NEARCTIC-HAWAIIAN FLYWAY
Regular Visitors Uncommon? Visitors
_Pluvialis dominica fulva_* _Squatarola squatarola_*
_Numenius tahitiensis_* _Charadrius hiaticula semipalmatus_[+]
_Heteroscelus incanus_* _Charadrius v. vociferus_
_Arenaria i. interpres_* _Limosa lapponica baueri_*
_Crocethia alba_* _Tringa melanoleuca_*[+]
_Phalaropus fulicarius_ _Gallinago delicata_
_Phalaropus lobatus_*? _Erolia melanotos_*
_Erolia acuminata_*
* Indicates species which are found in Micronesia.]
[+] Indicates species not recorded from the Hawaiian Islands; see Bryan
and Greenway (1944:109-115).]
POPULATIONS OF SHORE BIRDS IN MICRONESIA
Although shore birds have been observed in Micronesia on many occasions,
actual counts of numbers of individuals of the different birds have
rarely been made. Kubary, Finsch, Marche, Seale and other early
collectors and observers record some data of this kind as have the
Japanese investigators in later times. William Coultas of the Whitney
South Sea Expedition obtained considerable information of this nature at
Guam, Saipan, Kusiae, Ponapé, and the Palaus, but it is unpublished. His
records were made in fall, winter and spring, when migrants were present
in large numbers and these observations offer evidence that many of the
migrants are comparatively numerous, especially in the Carolines,
throughout the winter months. McElroy's observations made on his trip
for NAMRU2 to Truk in December, 1945, offer further evidence of this.
TABLE 8. POPULATIONS OF MIGRATORY SHORE BIRDS SEEN AT GUAM IN 1945
Column headings:
A: _Pluvialis dominica_
B: _Charadrius mongolus_
C: _Numenius phaeopus_
D: _Actitis hypoleucos_
E: _Heteroscelus_ spp.
F: _Heteroscelus incanus_[+]
G: _Heteroscelus brevipes_[+]
H: _Limosa lapponica_
I: _Arenaria interpres_
J: Unidentified
K: Total No. of individuals
L: Total No. of species
=============+====+====+====+====+====+====+====+====+====+====+====+====
| A | B | C | D | E | F | G | H | I | J | K | L
-------------+----+----+----+----+----+----+----+----+----+----+----+----
March 11 | x | | | | | | | | | | x | 1
March 17 | 10 | | 1 | | 2 | | | | | | 13 | 3
March 19 | x | | x | | x | | | | x | | x | 5
April 24 | x | | | | | | | | | | x | 1
April 26 | | | | | | | | 1 | | | 1 | 1
May 19 | | | | | 3 | 2 | | | | | 5 | 1
May 21 | | | | | 4 | | | | | | 4 | 1
May 26 | | | | | x | 2 | | | | | x | 1
June 1 | | | 1 | | | | | | | | 1 | 1
June 6* | | 1 | x | | x | | 1 | | | x | x | 4
June 11 | | | 1 | | | | | | | | 1 | 1
June 12 | | | 12 | | 2 | | | | | | 14 | 2
June 22 | | | 2 | | | | | | | 1 | 3 | 2
June 30 | | | | | | | | | | 2 | 2 | 1
July 7 | | | 2 | | | | | | | | 2 | 1
July 8 | 3 | | x | | 1 | | | | | | x | 3
July 16* | 6 | | 3 | 3 | 4 | | 1 | | | | 17 | 4
July 19 | x | | x | | x | | | | | | x | 3
July 24* | 10 | | 6 | | 3 | | 2 | | 3 | 5 | 29 | 5
July 26 | | | 8 | | | | | | | | 8 | 1
August 2 | | | x | | | | | | | x | x | 2
August 3 | | | 1 | | | | | | | | 1 | 1
August 6* | | | 6 | | 12 | | | | | | 18 | 2
September 29 | x | | x | | | | | | x | | x | 2
October 3* | x | | | | x | | | | | | x | 2
October 10 | x | | x | | x | 2 | | | x | | x | 4
October 11 | | | | | | | | | 2 | | 2 | 1
October 23* | x | | x | | x | 1 | 1 | | x | | x | 5
October 24 | x | | | | | | | | | | x | 1
-------------+----+----+----+----+----+----+----+----+----+----+----+----
x Observed but numbers not recorded.
* Observations made on beach at Agfayan Bay area.
[+] Figures based on identified skins.
None of the above workers, however, obtained very much information on
comparative numbers of species.
Tables 8, 9, and 10 present the writer's findings on populations of
migratory shore birds in Micronesia in 1945. At Guam, as shown in table
8, the records for March, April and early May are few, owing to a
limited amount of field observation. Beginning in late May and until
October 24 a greater amount of time was spent in the field and more
regular records were obtained. No observations were made by the author
at Guam in the period from August 11 to September 25. The dates marked
with an asterisk are those on which observations were made on the
extensive tidal flats at Agfayan Bay and vicinity. These flats, at low
tide, present excellent feeding grounds for waders and in 1945 were
undisturbed by parties of service personnel, because the area was
"off-limits."
Table 8 shows that _Pluvialis dominica_, _Numenius phaeopus_, and
_Heteroscelus_ spp. were the shore birds most frequently found at Guam
in this period. _Pluvialis dominica_ was the most numerous of the three
species. Of _Heteroscelus_ there was approximately equal representation
of _H. incanus_ and _H. brevipes_ as indicated by specimens collected.
These birds were not identified to species in the field.
Although records were made only infrequently in the spring migration,
such information as was obtained indicates that the populations were
largest in March and early April. On April 24, _Pluvialis dominica_ was
the only bird observed on beaches and in upland openings. On April 26, a
single _Limosa lapponica_ was recorded. On May 15, no shore bird was
seen on a trip along several beaches. In late May and early June, single
individuals of _Heteroscelus_ were found. Of this genus, those collected
in May were in nuptial plumage, and those collected in June were in
winter plumage and probably should be classed as non-migrants. _Numenius
phaeopus_ was occasionally recorded beginning in early June, but waders
were totally absent from beaches at Agfayan Bay and vicinity on June 18
and 19. Few shore birds were seen in early August. In late September,
birds, especially _Pluvialis dominica_, _Numenius phaeopus_, and
_Heteroscelus_ spp., were numerous. These species were numerous until
October 24, when observations were discontinued.
Of the 17 species of migratory shore birds recorded from the Mariana
Islands, eight were identified. Of these eight, three species, _Limosa
lapponica_, _Actitis hypoleucos_, and _Charadrius mongolus_, were found
on only one occasion. Never more than four species were identified on a
single field trip. These data give an idea of the lack of variety of
species that may be observed on Micronesian islands.
TABLE 9. POPULATIONS OF MIGRATORY SHORE BIRDS SEEN AT ULITHI ATOLL IN 1945
Column headings:
Fas.: Fassari
Man.: Mangejang
Los.: Losiep
======================+================================================
| ISLAND AND DATE
+-----------------------+-----+-----+-----+------
SPECIES | Potangeras | Fas.| Man.| Pau | Los.
+-----------------------+-----+-----+-----+------
| Aug.| Aug.| Aug.| Aug.| Aug.| Aug.| Aug.| Aug.
| 14 | 15 | 16 | 17 | 19 | 20 | 21 | 22
----------------------+-----+-----+-----+-----+-----+-----+-----+------
_Pluvialis dominica_ | | | 6 | 5 | 4 | | 10 | 5
_Charadrius mongolus_ | | | | | | | x | 2
_Numenius phaeopus_ | 1 | 4 | | 1 | | | 1 | 2
_Actitus hypoleucos_ | | | | | | | 2 | 2
_Heteroscelus_ spp. | | | | | 2 | | 6 | 3
_H. incanus_* | | | | | | 1 | | 2
_Crocethia alba_ | | | | | | | 30 | 5
+=====+=====+=====+=====+=====+=====+=====+======
Total No. | | | | | | | |
of Individuals | 1 | 4 | 6 | 6 | 6 | 1 | 49 | 21
Total No. of | | | | | | | |
Species | 1 | 1 | 1 | 2 | 2 | 1 | 6 | 6
----------------------+-----+-----+-----+-----+-----+-----+-----+------
x Observed but numbers not recorded.
* Figures based on identified skins.
Table 9 lists the shore birds seen at Ulithi Atoll, Caroline Islands, on
eight field excursions in the period from August 14 to August 22, 1945.
Of seven species of shore birds known to visit the atoll, six were taken
in this period. As observed at Guam, _Pluvialis dominica_ and _Numenius
phaeopus_ were the species most frequently found. _Heteroscelus_ was
seen on three occasions; those collected were identified as _H.
incanus_. Most of the shore birds were seen at Pau and Losiep, islands
unoccupied by man. Similar tidal flats are present at most of the other
small islands in the atoll, but these islands (Asor, Fallalop,
Potangeras, Fassarai and Mangejang were visited) were occupied by small
detachments of service personnel or by natives, which may have tended to
keep many of the shore birds away. At the more populated islands of Asor
and Fallalop, no shore birds were seen. Almost as many species were
recorded at Ulithi on the eight field trips as were found by the author
at Guam in eight months of observations.
TABLE 10. POPULATIONS OF MIGRATORY SHORE BIRDS SEEN AT THE PALAU ISLANDS
IN 1945
=======================+==========================================+======
| Peleliu |Angaur
+---------+--------------------------------+------
SPECIES | August | September |
+----+----+----+----+----+-----+-----+-----+ Sept.
| 24 | 28 | 1 | 6* | 8* | 9[+]| 16* | 20* | 21
-----------------------+----+----+----+----+----+-----+-----+-----+------
_Pluvialis dominica_ | x | | x | x | 25 | | 20 | x | x
_Charadrius mongolu_ | | | | x | 25 | | 5 | x | x
_C. leschenaultii_ | | | | x | 25 | | 5 | x | x
_Numenius phaeopus_ | | | 3 | x | 30 | | 20 | x | x
_N. madagascariensis_ | | | | | 1 | 1 | | 15 |
_Limosa lapponica_ | | | | | 3 | | 4 | |
_Tringa nebularia_ | | 6 | | | | | 3 | |
_T. glareola_[++] | | | | | | | | | 1
_Actitis hypoleucos_ | | | | | | 2 | | |
_Heteroscelus_ sp. | | | x | x | 75 | | x | x | x
_H. brevipes_[++] | | | | 3 | 2 | | 2 | |
_Arenaria interpres_ | | | | | 20 | | | |
_Capella megala_ | | | | | | | | | 4
_Calidris tenuirostris_| | | | | 15 | | 20 | |
_Erolia minuta_ | | | | x | 50 | | 50 | x | x
_E. acuminata_[++] | | | | | | | | | 3
_E. ferruginea_[++] | | | | 1 | | | | |
_Limicola | | | | | | | | |
falcinellus_[++] | | | | | | | | | 1
Unidentified | x | | | x | x | | x | x | x
+====+====+====+====+====+=====+=====+=====+======
Total number
of individuals | x | 6 | x | x |271+| 3 |129+ | x | x
Total
number of species | 1 | 1 | 3 | 7 | 10 | 2 | 9 | 7 | 10
-----------------------+----+----+----+----+----+-----+-----+-----+------
* Observations made on beaches at Akarakoro Point, Peleliu.
[+] Observations made at fresh water ponds.
x Observed but numbers not recorded.
[++] Figures based on identified skins.
Table 10 presents field counts at the Palau Islands in the period from
August 24 to September 21, 1945. Of 20 species of shore birds known from
the Palaus, 17 species were collected or identified on this trip. It was
apparent that the fall migration was at its height at this time. Birds
were numerous at inland openings and ponds, air field strips, and on the
extensive tidal flats at Akarakoro Point. The latter area is between
Peleliu and the adjacent island of Ngesebus to the north. Several
observations were made at this area (as indicated by the dates marked
with asterisks in the table); on September 8, 271+ shore birds were
counted; on September 16, 129+ were counted. Six species were observed
to be abundant. The majority of the birds found at these beaches were in
small flocks which consisted of several birds of one or more species.
The birds observed at Angaur on September 21 were seen at several fresh
and brackish ponds. Four species (_Tringa glareola_, _Erolia acuminata_,
_Limicola falcinellus_, _Gallinago megala_), which were not taken on the
tidal flats or elsewhere at Peleliu, were found at these ponds.
The abundance, and more especially the variety, of shore birds at the
Palau Islands during this period was in marked contrast to the smaller
and less diversified populations of shore birds in rather similar
insular environments at Ulithi and Guam. These differences offer support
for the supposition that the Asiatic-Palauan Migratory Shore Bird Flyway
is distinct from the Japanese-Marianan Migratory Shore Bird Flyway.
LAND AND FRESH-WATER BIRDS
The land and fresh-water avifauna of Micronesia consists of 147 kinds of
birds. Of these, 37 kinds are non-residents, 104 kinds are residents,
and 6 kinds have been introduced by man. The 104 resident birds include
98 kinds (94 percent) which are found only within the confines of
Micronesia. Included in these 98 kinds which are restricted to
Micronesia are 5 endemic genera, 31 endemic species and 76 endemic
subspecies.
Gulick (1932: 407, 413) stresses that the fauna and flora of the oceanic
islands may be "disharmonic" (he uses Easter Island as his example) and
says, "It is evident that mature groups of islands will attain an
internal harmony, from the standpoint of the systematist. But this
harmony, instead of reflecting the pre-existing harmony of some
continental source (as in the case of the continental islands or
land-bridge remnants) will be recognizably derivable by descent from a
quite limited number of original importations, at the start distinctly
miscellaneous and 'disharmonic'." Analysis of the land and fresh-water
avifauna of Micronesia supports Gulick's view.
[Illustration: FIG. 7. Divisions of the islands of part of the Pacific
Basin from the standpoint of the distribution of land birds and
fresh-water birds: (1) Micronesia; (2) Hawaii; (3) Central Polynesia;
(4) Eastern Polynesia; (5) Southern Melanesia; (6) Melanesia.]
As mentioned previously, the islands of Micronesia, from the
zoogeographical viewpoint, have been regarded as a part of the
Polynesian Subregion of the Australian Region. Mayr (1941a: 192) defines
the Polynesian Subregion as comprising "all the tropical and subtropical
islands of the Pacific Basin which indicate by their impoverished fauna
that they have had no recent continental connection (after early
Tertiary) and which derived the major part of their fauna directly or
indirectly from the Papuan Region or jointly from Australia and the
Papuan Region." As based on the distribution of the resident avifauna,
Mayr (1941a:193) subdivides the Polynesian Subregion into the following
districts: Micronesia ("including Palau, the Marianne, Caroline,
Marshall, and Gilbert islands"); Central Polynesia ("including Fiji,
Tonga, Samoa, Phoenix, Ellice, Union islands, and a number of small
islands, such as Rotuma, Fotuna, Keppel, Niue, Niouafu, and Uvea");
Eastern Polynesia ("all the islands east of 165° W"); and Southern
Melanesia ("including the Santa Cruz group, Banks Islands, New Hebrides,
Loyalty Islands, and New Caledonia"). He considers that the Hawaiian
Islands, Solomon Islands, and possibly New Caledonia are bordering
districts to the Polynesian Subregion. Figure 7 shows the divisions of
the islands of the Pacific Basin from the standpoint of the distribution
of the land and fresh-water birds. I have placed the Gilbert and
Marshall islands in the Central Polynesian rather than in the
Micronesian District. For purposes of discussion in this report,
however, I am considering the Marshalls to be a part of Micronesia. The
birdlife of the Bonin and Volcano islands northward of the Marianas is
regarded as having its closest affinities to the Japanese avifauna. The
Papuan or Melanesian Subregion of the Australian Region includes the
districts of New Guinea and Northern Melanesia, including the Bismarck
Archipelago, the Admiralty Islands, and the Solomon Islands.
The resident land and fresh-water birds of Micronesia have been derived
from several sources. Studies of these birds and their closest relatives
in adjacent areas indicate that the avifauna has been derived from five
different sources: Polynesia, Melanesia, the Moluccas and Celebes,
Philippines, and Palearctica.
POLYNESIAN COMPONENT
_Aphanolimnas monasa_ (extinct?), _Ptilinopus porphyraceus_, and _Ducula
oceanica_ are the only species of birds which have reached Micronesia
directly from Polynesia. There are in Micronesia, as Mayr (1941b: 204)
points out, eight species "which are members of typically Polynesian
species or genera" and six species which are either Papuan or
Polynesian. The relationships between Polynesian and Micronesian birds
is evident, but insofar as the pathways of colonization are concerned
the majority of these Micronesian species listed by Mayr have come from
elsewhere than Polynesia and the birds of these two areas are thought to
have arisen from common ancestors. _Aphanolimnas_, _Ptilinopus_, and
_Ducula_ apparently invaded Micronesia from Central Polynesia _via_ the
Marshall Islands through a rather continuous chain of islands and
atolls. _Aphanolimnas_ is known only from Kusaie in the extreme eastern
part of the Carolines while _Ptilinopus_ and _Ducula_ are known from the
Marshalls, Carolines, and Palaus.
MELANESIAN COMPONENT
The Papuan or Melanesian Region (New Guinea, Bismarck Archipelago,
Solomon Islands) has supplied to Micronesia its greatest number of
endemic land and fresh-water residents. Fifty kinds of birds belonging
to the following species reached Micronesia from Melanesia: _Nycticorax
caledonicus_, _Megapodius lapérouse_, _Ptilinopus roseicapillus_,
_Gallicolumba xanthonura_, _G. canifrons_, _Caloenas nicobarica_,
_Halcyon cinnamomina_, _Trichoglossus rubiginosus_, _Collocalia
inquieta_, _Edolisoma tenuirostre_, _Rhipidura rufifrons_, _Metabolus
regensis_, _Monarcha godeffroyi_, _M. takatsukasae_, _Colluricincla
tenebrosa_, _Aplonis opacus_, _A. pelzelni_, _A. corvinus_ (extinct?),
_Cleptornis marchei_, _Myzomela cardinalis_ (probably by way of Southern
Melanesia), _Rukia palauensis_, _R. oleaginea_, _R. ruki_, _R.
sanfordi_, _Erythrura trichroa_. The colonization of Micronesia by these
species has probably extended over a considerable period of time.
_Megapodius_, _Trichoglossus_, and _Aplonis corvinus_ may represent
older colonizations which have become well differentiated from the
ancestral forms; _Nycticorax_, _Myzomela_, and _Erythrura_ may have
become established later and have had "less time" to become modified
from the ancestral forms. Birds from Melanesia have reached Micronesia
probably by direct flight to the Caroline Islands. Aided by favorable
winds which blow from the southwest, south and southeast during the
period from May to November, birds, particularly the young of the year,
might conceivably be blown in the direction of the Carolines, where 57
percent of the birds derived from Melanesia reside. The Palaus are
populated with 15 percent, the Marianas with 28 percent, and the
Marshalls (lacking "high" islands) with none; these may be secondary
colonizations from the Carolinas excepting _Ptilinopus_, _Megapodius_,
_Gallicolumba canifrons_, _Cleptornis_, and _Colluricincla_. The
Marshall Islands have received no avian components from Melanesia. The
absence of "high" islands in the Marshalls and the possible inability of
birds accustomed to life on the luxuriant islands of Melanesia to become
established on relatively barren atolls are logical reasons for this.
Instead of New Guinea itself, the outlying islands of Melanesia
(Bismarck Archipelago, Solomons, Southern Melanesia) probably have been
the principal "taking-off" places for birds invading Micronesia.
MOLUCCAN AND CELEBESIAN COMPONENTS
Birds which reached Micronesia by way of the islands of Celebes and the
Moluccas may have been derived originally from Melanesia. The following
birds appear to have used this route: _Porphyrio porphyrio_, probably
_Halcyon chloris_, _Rhipidura lepida_, _Myiagra oceanica_, _Zosterops
conspicillata_, and _Z. cinerea_. These birds apparently became
established initially in the Palaus; _Porphyrio_ and _Rhipidura lepida_
have not been recorded elsewhere in Micronesia, but _Myiagra_ and the
two species of _Zosterops_ have spread to the Carolines and Marianas,
although not into the Marshall Islands. Wind from the southeast in
summer and fall has probably been a factor aiding these colonizations.
The population of _Gallinula chloropus_ resident at Palau may also have
arrived by this route.
PHILIPPINE COMPONENT
Ten of the kinds of birds of Micronesia have come from or by way of the
Philippine area. These are known principally from the Palaus and the
Marianas and include: _Rallus philippinus_, _R. owstoni_, _Poliolimnas
cinereus_, _Caprimulgus indicus_, _Corvus kubaryi_, _Psamathia annae_,
_Artamus leucorhynchus_, possibly _Lonchura nigerrima_, and _Collocalia
inexpectata_. The Philippines may have been the actual point of
dispersal of the birds (example, _Psamathia_), or may have been used as
a stepping stone to Micronesia by birds coming from Melanesia (examples,
_Rallus_ and _Artamus_), by birds from Malaysia (example, _Collocalia_),
and by birds from Asia (example, _Caprimulgus_). Two birds of this
component have reached the islands of eastern Micronesia. A subspecies
of _Lonchura nigerrima_ is endemic at Ponapé, and a subspecies of
_Poliolimnas cinereus_ occurs on several islands in the Carolines and
has even been recorded at Bikini in the Marshall Islands. Three species
are known only from the Palaus; two are known only from the Marianas.
PALEARCTIC COMPONENT
[Illustration: FIG. 8. Faunal areas from which the resident land birds
and fresh-water birds of Micronesia have been derived. (1) Palearctica;
(2) Philippines; (3) Moluccas and Celebes (Malaysia); (4) Melanesia (New
Guinea and northern Melanesia); (5) Polynesia.]
Birds of Micronesia which have been derived directly from Palearctica
are _Gallinula chloropus guami_, _Otus podarginus_, _Asio flammeus_,
_Acrocephalus luscinia_ and _Anas oustaleti_. Apparently _Gallinula_,
_Asio_, and _Acrocephalus_ arrived in Micronesia by way of the chain of
islands from Japan southward to the Bonins, Volcanoes, and Marianas.
_Otus_ reached Palau from Asia, possibly by way of the Philippines. The
smallness of the representation of this component may result partly from
lesser ability of the northern birds to adapt themselves to, and to
establish themselves on, the semi-tropical and tropical islands of
Micronesia as compared with birds from Melanesia where the climate and
ecologic conditions resemble more closely those found in Micronesia.
Evidence supporting this possibility is the large number of Palearctic
residents in the Bonin and Volcano islands as compared with fewer in the
Marianas; the Bonins and Volcanoes are less tropical and more temperate
in climate.
Table 11 lists the birds concerned, by faunal areas from which the birds
have been derived and shows the number of kinds of birds which are
present as a result of these colonizations. There is some overlap in the
numbers since some endemics may be found in more than one area in
Micronesia. Figure 8 shows the faunal areas from which the endemic land
and fresh-water birds of Micronesia have been derived. Melanesia (Papua)
supplied 52 percent of this population. Birds reaching Micronesia by way
of the Moluccas and Celebes include 21 percent of the total population.
The Philippines have supplied 10 percent; Polynesia, 9 percent; and
Palearctica, 8 percent. This population of endemic land birds and
fresh-water birds has seemingly evolved from 46 colonizations, of which
27 have been derived from Melanesia, 6 from the Philippines, 5 from the
Moluccan and Celebean areas, 5 from Palearctica, and 3 from Polynesia.
The Palaus have received a large part of their avifauna from the west
(Moluccas, Philippines, Palearctica). Their Melanesian component is
mostly the result of secondary colonization from the Carolines. The
Carolines have received a greater share of their land birds and
fresh-water birds from Melanesia and a smaller share from Polynesia. The
Marshalls are definitely associated with the Polynesian element. The
Marianas exhibit a considerable amount of secondary colonization from
other Micronesian islands, as well as some unique components from the
Philippines, Melanesia, and Palearctica. Thus, the number of endemics in
Micronesia provides little information concerning the actual number of
successful colonizations by birds from other areas. Many of the endemics
probably have resulted in this way: Individuals of an endemic subspecies
flew to another island and there underwent further differentiation,
producing another endemic subspecies. Such secondary colonization
probably is going on now.
This analysis of the avifauna shows that Micronesia, with the exception
of the Marshall Islands (and the Gilbert Islands), has but little
affinity to Polynesia. It has greater affinity, from the zoogeographical
standpoint, with the Papuan Region (Melanesia).
TABLE 11. AVIFAUNAL COMPONENTS WHICH MAKE UP THE ENDEMIC RESIDENT LAND
AND FRESH-WATER BIRD POPULATION OF MICRONESIA
=================+=======+=============+===========+==========+==========
| | Western | | |
FAUNAL COMPONENT | Palau | and central | Eastern | Marianas | Marshalls
| | Carolines | Carolines | |
-----------------+-------+-------------+-----------+----------+----------
Polynesian | 2 | 3 | 5 | 0 | 3
Melanesian | 11 | 14 | 16 | 12 | 0
Moluccan-Celebean| 6 | 3 | 4 | 7 | 0
Philippine | 6 | 2 | 2 | 4 | 1
Palearctic | 2 | 1 | 2 | 5 | 0
+-------+-------------+-----------+----------+----------
Totals | 27 | 23 | 29 | 28 | 4
-----------------+-------+-------------+-----------+----------+----------
SPECIATION
Of the 104 native fresh-water birds and land birds which are resident in
Micronesia, only 7 kinds or 6.5 percent remain undifferentiated from
populations elsewhere. These birds are _Phalacrocorax melanoleucus_,
_Pandion haliaetus_, _Demigretta sacra_, _Ixobrychus sinensis_, _Anas
poecilorhyncha_, and possibly _Lonchura punctulata_ (may be an
introduction by man). Another bird, _Gallinula chloropus_, a resident at
Palau, may or may not be distinct from the gallinule of Malaysia, _G. c.
orientalis_. Of the 104 resident birds, 97 kinds or 93.5 percent have
become differentiated and can be separated taxonomically from
populations elsewhere. Of the kinds of birds which are found only in
Micronesia, there are 5 endemic genera (16 percent), 31 endemic species
(32 percent) and 76 endemic subspecies (75 percent). If we consider the
avifauna of Micronesia as a single element, the endemism is high as
compared with that on larger and less isolated islands. For example,
Mayr (1944a:174) found 137 resident birds on Timor including 22 endemic
species (16 percent) and 67 endemic subspecies (47.5 percent).
Stresemann (1939b:313) found 220 species including 84 endemic species
(38.2 percent) on Celebes. Mayr (1944a:174) also writes that on Java, of
337 breeding species, 16 (4.8 percent) are endemic, and on New
Caledonia, of 68 species 19 (27.9 percent) are endemic. Speciation in
Micronesia has not progressed much farther than that at New Caledonia
and not so far as at Celebes, but subspeciation has progressed
considerably more than at the island of Timor. The avifauna of the
Hawaiian Islands, as recorded by Bryan and Greenway (1944), has 73
resident land birds and fresh-water birds, all of which are endemic,
including one family, 23 genera and 36 species. The North American night
heron, _Nycticorax n. hoactli_, may be included in this list as the only
resident which is undifferentiated. The development of full specific
differentiation within the resident avifauna is greater in the more
isolated Hawaiian chain where 49 percent of these birds are regarded as
endemic species, while in Micronesia, which is less remote from other
bodies of land, the specific endemism is only 32 percent.
TABLE 12. ENDEMISM IN FAMILIES OF NATIVE LAND AND FRESH-WATER BIRDS IN
MICRONESIA
==================+===========+=========+=========+============+=========
| | Endemic | Endemic | Endemic | Total
FAMILY | Residents | genera | species | subspecies | endemic
------------------+-----------+---------+---------+------------+---------
Phalacrocoracidae | 1 | 0 | 0 | 0 | 0
Ardeidae | 3 | 0 | 0 | 1 | 1
Anatidae | 2 | 0 | 1 | 0 | 1
Accipitridae | 1 | 0 | 0 | 0 | 0
Megapodidae | 2 | 0 | 1 | 2 | 2
Rallidae | 7 | 1* | 2 | 4 | 6
Columbidae | 13 | 0 | 4 | 11 | 13
Psittacidae | 1 | 0 | 1 | 0 | 1
Strigidae | 2 | 0 | 1 | 1 | 2
Caprimulgidae | 1 | 0 | 0 | 1 | 1
Apodidae | 5 | 0 | 1 | 5 | 5
Alcedinidae | 7 | 0 | 1 | 7 | 7
Campephagidae | 3 | 0 | 0 | 3 | 3
Corvidae | 1 | 0 | 1 | 0 | 1
Sylviidae | 5 | 1 | 2 | 4 | 5
Muscicapidae | 14 | 1 | 6 | 9 | 14
Artamidae | 1 | 0 | 0 | 1 | 1
Sturnidae | 9 | 0 | 3[+] | 7 | 9
Meliphagidae | 7 | 1 | 1 | 6 | 7
Zosteropidae | 14 | 1 | 6 | 10 | 14
Ploceidae | 5 | 0 | 0 | 4 | 4
+-----------+---------+---------+------------+---------
Totals | 104 | 5 | 31 | 76 | 97
------------------+-----------+---------+---------+------------+---------
* _Aphanolimonasa_ is included but may be extinct.
[+] _Aplonis corvinus_ is included but may be extinct.
Table 12 lists the families of land birds and fresh-water birds which
have resident members as part of the avifauna of Micronesia. It can be
observed from the table that only two families are represented by no
endemic kinds, several families are represented by one or two endemic
kinds, and others are represented by as many as 14 endemic kinds.
Endemism has reached its greatest development in the families Rallidae
(6), Columbidae (13), Apodidae (5), Alcedinidae (7), Sylviidae (5),
Muscicapidae (14), Sturnidae (9), Meliphagidae (7), and Zosteropidae
(14). Generic endemism is greatest in the Sylviidae where one endemic
genus occurs among 5 endemic species and subspecies (20 percent), in
Rallidae one in 6 (17 percent), in Meliphagidae one in 7 (14 percent).
Specific endemism is greatest in Psittacidae and Corvidae where the
single representative of each family in Micronesia is considered
specifically distinct (100 percent), in Megapodidae and Strigidae one in
2 (50 percent), in Muscicapidae and Zosteropidae 6 in 14 (43 percent) in
Sylviidae 2 in 5 (40 percent), in Rallidae 2 in 6 (33 percent), in
Sturnidae 3 in 9 (33 percent) in Columbidae 4 in 13 (31 percent).
Subspeciation within species which are endemic in Micronesia has
occurred in 8 families, occurring within two species in each of the
families Columbidae and Zosteropidae and once in each of the families
Megapodidae, Apodidae, Alcedinidae, Sylviidae, Muscicapidae, and
Sturnidae.
In summary, the families of land and fresh-water birds found in
Micronesia which have the greatest number of endemic forms are
Muscicapidae (14), Zosteropidae (14), Columbidae (13), and Sturnidae
(9). Speciation has occurred in the single representative of the
families Psittacidae (_Trichoglossus rubiginosus_) and Corvidae (_Corvus
kubaryi_). Where family representation is large, speciation has occurred
most frequently, as in the Muscicapidae (6 in 14 = 43 percent), in the
Zosteropidae (6 in 14 = 43 percent), and in the Columbidae (4 in 13 = 31
percent). Subspeciation has occurred in 8 families, in two species in
the Columbidae and Zosteropidae and in one species in each of 6 other
families.
TIME OF COLONIZATION
Previously (and in the accounts of the species to follow), comments are
made concerning the subjects of _from where_ and _by what route_ the
various kinds of birds have arrived at Micronesia. The problem of _when_
these birds arrived is a difficult and usually unanswerable one.
Although geology provides some evidence on the relative age of the
islands, and although deposits of bird guano on now elevated coral
islands show that oceanic birds have inhabited these islands for a long
time, there is no evidence to show the time of the first colonization by
land birds. No fossil remains of land birds or fresh-water birds have
been found in Micronesia. The relative extent of differentiation in
color and structure, which has taken place between different birds,
offers one means for estimating the relative length of residence in the
area, provided all other factors are equivalent. Concerning the birds of
the Galapagos, Lack (1947:113) writes "That Darwin's finches are so
highly differentiated suggests that they colonized the Galapagos
considerably ahead of the other land birds." Evidence from this source
actually is of little value, because the speed of evolution is unknown
and its rate may be different in different species, even though they
live under the same circumstances. Dobzhansky (1941) says that evolution
is a modification of the genetic equilibrium, which, if true, may not
result in similar manifestations in different kinds of birds living
under the same conditions of life. Relative antiquity of the birds might
be ascertained by measuring their ecologic adaptations. The Guam Rail
(_Rallus owstoni_) and the Micronesian White-browed Rail (_Poliolimnas_)
can be examined in this way. _R. owstoni_ has the ability to live in
both brackish and fresh water swamps, as well as in the scrub and grass
of the uplands and in the virtually barren, rocky areas in the dense
jungles. _Poliolimnas_, on the other hand, appears to be restricted to
swampy areas in Micronesia. If the swampy areas were removed this rail
probably would become extinct. _R. owstoni_ appears to have been
resident in Micronesia longer than _Poliolimnas_. However, ability to
live in a variety of habitats might be acquired by _R. owstoni_ in a
relatively short time.
Another possibility is that the birds, which are less differentiated
from their ancestral stocks, may be less differentiated because of
suppression of newly evolved characters by dilutions, which result from
interbreeding with new birds, which may be arriving at irregular
intervals from the ancestral home. Interbreeding of the resident
population with newcomers may overshadow any modifications which might
have appeared as a result of insular isolation, especially modifications
which have little adaptive significance. One would suspect, from their
modifications, that _Rallus owstoni_, _Metabolus rugensis_, _Corvus
kubaryi_, and other endemic forms have experienced less of this
"dilution," than such birds as _Rallus philippensis pelewensis_,
_Artamus leucorhynchus pelewensis_, _Myzomela cardinalis_, and others.
Murphy (1938) mentions this "dilution" effect in his discussion of
"strong" and "weak" subspecies among warblers of the Marquesas. He
writes that "strong" subspecies may develop if the birds are present on
islands which are upwind from islands containing related subspecies. The
wind acts to block interisland migration in these weak-flyers. On the
other hand, "weak" subspecies may show the effect of "dilution," being
situated on islands downwind from islands containing related
subspecies. The direction of the wind acts to aid the weak flyers to
move to the downwind islands and continually "dilute" the resident
subspecies. Similar examples can be cited for Micronesian birds. Hesse,
Allee, and Schmidt (1937:87) write, "Endemism on islands is most
frequent in forms for which the difficulty of reaching the island is
most extreme, so that new increments of the parent form are unlikely to
follow."
Employing the criteria mentioned above, the birds of Micronesia can be
tentatively divided into four groups as regards the relative time when
they arrived at the islands:
1. Birds of ancient colonizations which reached certain individual
islands, became modified, and dispersed no farther. Examples are
_Aphanolimnas_, _Rallus owstoni_, _Aplonis corvinus_, _Metabolus
rugensis_, and _Corvus kubaryi_.
2. Birds of ancient colonizations which reached or dispersed through a
number of islands but are now restricted to relatively few islands.
Examples are _Ducula oceanica_, _Ptilinopus porphyraceus_, _Megapodius
lapérouse_, _Asio flammeus_, and _Acrocephalus luscinia_.
3. Birds of ancient, or possibly more recent, colonizations which
initially reached or subsequently dispersed to many of the islands of
Micronesia possessing habitat suitable for them. Examples are _Myzomela
cardinalis_, the two species of _Halcyon_, _Aplonis opacus_, and
_Zosterops conspicillata_.
4. Birds of rather recent colonizations, which may have reached only a
few islands and are relatively unmodified from their parental stocks.
Examples are _Artamus leucorhynchus_, _Caprimulgus indicus_,
_Poliolimnas cinereus_, and _Nycticorax caledonicus_.
FACTORS CAUSING DISPERSAL
Darlington (1938:274) in discussing the origin of the fauna of the
Greater Antilles uses the term "over-water dispersal" in referring to
the spread of terrestrial animals across water. He is against the use of
the term "accidental dispersal" since many factors besides accident are
involved. He contends, as do others, that certain forms of organisms,
owing to their "nature and behavior" cross water barriers more
successfully than others. These observations may be applied to the
"over-water dispersal" of birdlife to the islands of Micronesia. Certain
groups of birds are more evident in Micronesia than others. Certain
groups of birds which are found on other islands of the Pacific basin
are found in Micronesia only in small numbers or may not be
represented; Mayr (1945a:284) writes, "Remarkable is the almost complete
absence of parrots and honey-eaters, the small number of pigeons and the
absence of such widespread genera as _Lalage_, _Turdus_, and
_Pachycephala_." The absence of some species and the presence of others
produces the characteristic insular effect termed "disharmonic" by
Gulick (1932:407), as compared with the continental area or island which
derived its avifauna by way of a land bridge. One would think from
looking at table 12 that members of the families Rallidae, Columbidae,
Muscicapidae, Sturnidae, and Zosteropidae were the most successful
colonizers in Micronesia on the basis of the number of successful
colonizations (not necessarily on the number of endemics developed from
a single colonization). Of these families, Sturnidae and Zosteropidae
and possibly Columbidae contain species which often move in flocks.
Furthermore, these families as well as the Muscicapidae feed on either
fruits, seeds, or insects, any one of which is a type of food which
might "give out" suddenly, stimulating a migratory behavior within the
birds. From a flock embarking seaward in "search" of more food, a part
or even all of the birds might survive in a chance flight to an isolated
island in Micronesia. If a flock containing both males and females
reaches an island, the species has a good chance of becoming
established. Evidence that such a rapid colonization by flocks of birds
can take place is found in the remarkable colonization of New Zealand by
_Zosterops lateralis_ from the Australian area. The bird was first seen
as a winter migrant in New Zealand in 1856 and records of nestings were
obtained at North Island in 1862, according to Oliver (1930:489). In the
case of rails there is no evidence that they move in flocks; however,
they are among the most successful colonizers and are on many of the
oceanic islands in the tropical and subtropical oceans. Representatives
of several species of the family Rallidae have invaded Micronesia and
have successfully established 6, or possibly 7, "colonies."
Darlington (1938:274) further writes that "it is no accident that some
islands, because of their nature and position, the direction of winds
and currents, and the nature of the neighboring land, receive more
organisms than other islands do." Semper (1881:294) writes that the
distribution of flying creatures "must be in a great degree dependent on
the direction and strength of atmospheric currents." These statements
are applicable to the history of the avifauna of Micronesia. The
Caroline Islands, for example, present a "broad front" for wanderers
from the Melanesian islands. As mentioned previously, the prevailing
winds in the late spring, summer, and early fall are from the south,
southwest, and southeast and would favor bird flight to the northward
towards the Carolines. In addition, the breeding season of many of the
birds in Melanesia is from November to February, and in the spring and
summer, restless young birds seeking living space might fly seaward and
aided by the winds fly northward towards Micronesia. Adults, which may
have well-established home territories, may be less likely to attempt
such a movement.
One could conclude from the above discussion that the Micronesian
islands, especially the Carolines, might be well populated with a large
variety of birds from Melanesia, a scant 500 or more miles away. As it
turns out, there are only a few islands in this extensive archipelago
possessing proper vegetation, fresh water, and other qualities which
make them capable of supporting the land and fresh-water birds of
Melanesia. The few islands which have these qualities are the so-called
"high" islands, including the entire Mariana chain, the Palaus, and four
widely separated islands in the Carolines: Yap, Truk, Ponapé, and
Kusaie. The other islands of Micronesia are "low" coral islands, which
often lack fresh water and have a meager variety of fruits, insects and
other foods. Thus, if birds do reach Micronesia but arrive at the atolls
instead of the "high" islands, these birds may be doomed. It is
noteworthy that the Micronesian islands are small compared with the
Solomons, Fijis, and others. The smaller the island, the fewer the
number of ecologic niches and the fewer the kinds of birds present.
Mayr (1941b:215) writes that the distance from the nearest land mass and
the climatic conditions are important factors controlling dispersal.
With regard to the degree of remoteness of the islands, table 13 lists
the number of resident land and fresh-water birds present in the Palaus
and the "high" islands of the Carolines. Also, the approximate distance
from the nearest large land mass and the area in square miles are given.
There is some correlation between the distance from the nearest land
mass and the number of resident land birds and fresh-water birds. For
example, Palau, with 32 resident birds, is only 410 miles from the
nearest land mass whereas Kusaie, with only 11 resident birds, is 720
miles from the nearest land mass. The comparative size of the land mass
must also be taken into account, as shown by the fact that the large
island of Ponapé contains more kinds of birds but is more remote from
large land masses than either Yap or Truk.
TABLE 13. CORRELATION BETWEEN NUMBER OF RESIDENT LAND AND FRESH-WATER
BIRDS AND DISTANCE FROM LARGE LAND MASSES OF "HIGH" ISLANDS OF
MICRONESIA
Column headings:
A: No. of Birds
B: Approximate distance from nearest land mass (statute miles)
C: Area in square miles
========+====+=====+===================================+=====
ISLAND | A | B | Nearest land mass | C
--------+----+-----+-----------------------------------+-----
Palau | 32 | 410 | Approximately equal distance from | 171
| | | Mindanao, Morotai, New Guinea |
| | | |
Yap | 13 | 580 | New Guinea | 83
| | | |
Truk | 17 | 525 | New Ireland | 50
| | | |
Ponapé | 20 | 630 | New Ireland | 145
| | | |
Kusaie | 11 | 720 | Malaita (Solomons) | 42
--------+----+-----+-----------------------------------+-----
Climatic factors are important in the dispersal of bird life;
Micronesia, where the climate is tropical to subtropical, is better
suited for colonization by birds from the tropics (Melanesia) than by
birds from the temperate or cold climates (Palearctica). The climatic
factor may be one of the principal reasons why birds from Palearctica
make up only a small part of the avifauna of Micronesia.
ANALYSIS OF SPECIATION
The process of speciation within insular populations has been discussed
by many authors. Hesse, Allee, and Schmidt (1937:517) list the motives
for differentiation as, "Special character of insular faunae rests on
the conditions common to all islands--isolation, freedom from
competition, space restriction, and special insular climates." This
combination of characteristics is seldom found elsewhere in nature, and
as Murphy (1938:357) points out, an island is the nearest approach to a
"man-controlled laboratory." Isolation of small populations is probably
the most influential factor in the process of speciation in insular
organisms. Lack (1947:134) writes that "in all organisms the isolation
of populations is an essential preliminary to the origin of new
species." Buxton (1938:265) also stresses this point with regard to the
formation of species of insects in Samoa and emphasizes that evolution
may occur more quickly in small populations. When mutations appear in
such small and isolated populations, they have a greater chance to
become fixed than do mutations in less restricted populations in a
larger land mass, where such a mutation might be lost by the swamping
effects of outbreedings. In addition, Wright (1931 and elsewhere)
suggests the possibility of change by accidental elimination and
recombination of hereditary characters in micropopulations. This
mechanism could well be a factor in Micronesian bird populations, many
of which possess no more than a few hundred individuals. Huxley
(1938:256) emphasizes that "accidental" mutations may be perpetuated in
small, isolated groups. It might be added that such changes might be
either advantageous or disadvantageous to the organism concerned. Huxley
(1938:263) states also that geographic isolation may promote nonadaptive
differentiation, which may be caused by "colonization by a random
sample" or by subsequent "preservation of nonadaptive mutations in
numerically small isolated groups." Mayr (1942b:237) cites the
importance of the "founder" principal for reduced variability in small
populations. He points out that if the "founders" of the population
carried with them only "a very small proportion of the variability of
the parent population," one would expect to see divergence from the
ancestral stock.
Freedom from competition, especially interspecific strife, is an
important factor in differentiation; this is especially true in the
early period of colonization. Lack (1947:113) points to the absence of
food competitors, especially in the initial period of colonization, as
an important influence in the evolution of Darwin's finches at the
Galapagos Islands. Once a population has become established and
"adjusted" to a given environment on a small island, intraspecific
competition might bring about adaptative selection. Subsequent colonists
might be eliminated by the competition brought about by these previously
adapted organisms, especially if both organisms were adapted for life in
the same ecologic niche. Space restriction may be important in such
Micronesian birds as _Rhipidura_ and _Myiagra_, which appear to possess
recognizable territories. A new colonist entering the territory of one
of these birds might be forced out. This competition might not play such
an important part among birds, which live in flocks and do not range in
closely guarded territories; birds in this group include some pigeons,
starlings, and white-eyes.
Freedom from the pressure of predation probably exerts a direct
influence on formation of species. Aside from a few migrant hawks and
two kinds of resident owls, most of the avifauna feeds on vegetable and
invertebrate foods. The large lizard _Varanus_ may be classed as the
only native predator on many of the islands. Man has been responsible
for the introduction of rats, house cats, and other mammals, which may
be destructive to birds. Thus, before the advent of man the factor of
predation may not have been of great consequence. As mentioned
previously, nonadaptive modifications may be perpetuated where the
"weeding-out" process by predation is not an influence. Flightless rails
have apparently developed in the absence of predation.
The absence of the pressure of predation should remove a certain amount
of control on the population turn-over. As Hesse, Allee, and Schmidt
(1937:521) write, a characteristic of the faunas of oceanic islands is
the fact that they are distinguished by the occurrence of
"disproportionately developed taxonomic groups in which one or a few
basic types have undergone adaptative radiation and come to fill unduly
large proportions of the population as compared with conditions that
obtain on neighboring continents." Lack (1947:114) writes, "that the
absence of predators may well have accelerated the adaptative radiation"
in the Galapagos finches. In Micronesia, the starling (_Aplonis opacus_)
dominates much of the available habitat on some of the Caroline atolls,
and even on "high" islands, where other land birds are present. There
appears to be no tendency towards selective adaptations occurring, or
towards ecologic isolation.
Available data indicate that the life spans of individual birds in
Micronesia may be short. For example, it was obvious on many of the
islands visited by the NAMRU2 party that starlings (_Aplonis opacus_) in
immature plumage outnumbered starlings in adult plumage, although it is
possible that immature plumages are retained longer in these island
birds than in others. Similar observations were made by Coultas, who
noted the ratio of birds in immature plumage to birds in adult plumage
at Kusaie to be 5 to 1. If the life span is shorter in these insular
forms as compared with that of the ancestral stocks, the higher annual
population turn-over would allow for the speed of genetic changes to be
accelerated.
The origin of species by hybridization between different kinds of
organisms has been a subject of frequent discussion. Lack (1947:100)
concludes that it is improbable that hybridization has played an
important part in the origin of new kinds of birds. Nevertheless, the
absence of sufficient mates in the confines of a small island probably
stimulates the crossbreeding between two species of birds. Fertile
offspring of such a cross might conceivably account for some of the
populations, the origins of which are puzzles to present day
taxonomists. Such Micronesian forms as _Metabolus_ and _Cleptornis_
could conceivably have been derived in such a manner. Yamashina (1948)
has described the origin of _Anas oustaleti_ as a result of
hybridization between _A. platyrhynchos_ and _A. poecilorhyncha_. It
might be difficult to explain every case of the formation of other
insular species on the basis of the effects of isolation and paucity
alone. However, Mayr (1942b:236) includes the development of
questionable and unusual kinds of insular forms in a general statement:
"The potentiality for rapid divergent evolution in small populations
explains also why we have on islands so many dwarf or giant races, or
races with peculiar color characters (albinism, melanism), or with
peculiar structure (long bills in birds), or other peculiar characters
(loss of male plumage in birds)."
Nutrition may be also a factor influencing speciation in bird life. The
types of food plants (coconut, papaya, breadfruit, pandanus, etc.) might
be similar on a Micronesian island and on a continental island in the
Philippine region; however, the value of these plants as foods might
vary and might reflect differences in mineral content of the soils. For
example, if the soils on an island lack, or by leaching out have lost,
sufficient amounts of potassium and other elements, plants may store
foods, not as proteins, but possibly as carbohydrates, simple sugars, or
alkaloids. Whether nutritional influences might have a selective effect
on the bird populations, has not been ascertained.
In summary, it may be said that genetic change altering the phenotypic
expression of avian characteristics is no more apt to happen in insular
populations than in continental populations but genetic change may have
a greater chance of being perpetuated in small insular populations where
isolation, limited competition, freedom from the selective influences of
predation, and other factors exert influences.
CONSERVATION OF THE AVIFAUNA OF MICRONESIA
The islands of Micronesia are small and their occupation by man often
produces serious effects on the endemic animal life of the islands. The
vulnerability of insular bird populations is well attested by the fact
that the majority of birds, which have become extinct in the past two
hundred years, have been insular forms. Two birds in Micronesia, the
Kusaie Rail (_Aphanolimnas_) and the Kusaie Mountain Starling (_Aplonis
corvinus_), are known to be either extinct or so rare that they have not
been taken since the time of Kittlitz, who visited the island of Kusaie
in December, 1827, and January, 1828. Other birds (_Anas oustaleti_,
_Caloenas nicobarica_, _Megapodius l. lapérouse_, and _Metabolus
rugensis_) have become reduced in numbers and may be threatened with
extermination.
Nelson (1921:270-274) has described the following agencies destructive
to island life of the Pacific: fire, volcanic eruptions, tidal waves,
hurricanes, clearing of the land, introduction of domestic animals and
grazing, introduction of wild animals and birds. Mayr (1945c) also
presents a discussion of conservation problems in these islands.
Fire is a serious hazard to island life, especially to the land birds.
It destroys both food and cover, these two habitat requirements being
most essential to the birds. The firing of open lands to improve grazing
conditions was a practice which persisted in the Marianas during the
time of the Spanish. This practice has declined, but the resultant
vegetational changes and erosion have adversely affected the avifauna.
Tidal waves and hurricanes (typhoons) are occasionally of such intensity
as to flood low coral atolls. Such events are damaging to, or might even
exterminate populations of land birds (_Aplonis_, _Acrocephalus_ and
others), and prevent colonizations which might otherwise occur. Clearing
of the land for agricultural use probably has affected the avifauna,
especially on the island of Tinian where much of the island has been
placed in cultivation. The occurrence of domestic stock, especially
feral hogs and cats, has affected the birds. Hogs, apparently, have been
in the islands for a long time. The English privateer, Lord Anson,
visited Tinian in October, 1742, and noted a large number of hogs
present at that time. At Guam, in 1945, the NAMRU2 party found both hogs
and cats moving freely in all parts of the island. Stomachs of cats
examined showed that they had been feeding principally on rodents.
Introduction of wild animals and plants have not been so extensive as in
the Hawaiians or other islands. There have been at least five
importations of land birds to Micronesia as well as several mammals,
other vertebrates and invertebrates. The effect of these established
colonies on the native bird life has not been studied.
The late world war has brought changes to the population of bird life in
Micronesia. The author (1946b) has elsewhere described some of the
effects of the bombing, invasion, and occupation of small islands. Some
islands, like Peleliu, suffered severely from bombing and invasion
operations. Some islands, especially smaller ones like Kwajalein and
Ulithi, were partly or almostly entirely cleared of vegetation by
occupation forces. Other effects were caused by "recreational" shooting
of birds by garrison forces; introductions of pests in materials
unloaded; and pest control by clearing, draining, and spraying with DDT
and other insecticides to the detriment of inoffensive species.
It is obvious that a well-planned program of conservation should be
placed in operation to insure survival of the endemic avifauna of
Micronesia.
THE FUTURE OF ORNITHOLOGICAL RESEARCH IN MICRONESIA
Collections of birds have been made at most of the major islands of
Micronesia, and it is thought that there are but few if any unnamed
birds in the region. The distribution of several species has not been
completely investigated, especially those land birds (_Ducula_,
_Ptilinopus_, and _Aplonis_) which inhabit coral atolls in the Carolines
and Marshalls. The bird life of the northern Marianas is also
incompletely known. Continued observations in the Micronesian islands
will increase our knowledge of the kinds of migratory shore birds and
migratory land birds which reach the island as winter visitors. Further
information is needed concerning the breeding activities of sea birds in
Micronesia, especially in the Marshalls and Carolines.
The systematic status of most of the birds in Micronesia is already
established. It is hoped that the present account advances our knowledge
of the methods of colonization. Although these fundamental
investigations have been nearly completed in Micronesia the field of
avian ecology has been relatively untouched. In the past, expeditions
have visited Micronesia with the aim of obtaining within a short time
collections of the animal life as large and as representative as
possible. Many of the collectors made few or no field notes on the bird
life; some, like Finsch, Kubary, Marche, and Coultas, made valuable
observations on the habits of the birds. Intensive ecological researches
may be accomplished more thoroughly by resident investigators, who can
devote full time to such pursuits.
METHODS AND ACKNOWLEDGMENTS
My own opportunity to study the bird life of Micronesia came as a member
of the scientific staff of the Laboratory of Mammalogy of United States
Naval Medical Research Unit No. 2 (NAMRU2) in the late war. The primary
duty of this laboratory was to obtain examples of the vertebrate fauna
for examination for ectoparasites by the Laboratory of Acarology and to
preserve specimens for identification. As a result sizeable collections
of mammals, birds, and other vertebrates were obtained. In addition,
ecological data were obtained (as time permitted), especially as an aid
in studying the distribution of ectoparasites which affected man. In
1945, I spent eleven months in Micronesia; for most of this time I was
stationed at Guam, the headquarters of the Unit, although one month was
spent in the Palau Islands, two weeks were spent at Ulithi Atoll, and
short stop-overs were made at Eniwetok and Kwajalein atolls. Other
members of the laboratory staff visited Rota and Truk islands.
Subsequent to the field studies in the Pacific, I was sent to Washington
and spent approximately eight months at the United States National
Museum studying the collections of birds and preparing several reports
for publication. In this period other material was studied, both in the
United States National Museum and at the American Museum of Natural
History, New York, and the literature dealing with the birds of
Micronesia was explored and a bibliography of Micronesian birds was
prepared. At the University of Kansas, I continued the bibliographic
work, borrowed and studied some specimens, and completed accounts of the
avifauna of Micronesia.
Under the account of each bird, all known references in the literature,
which mention the scientific name of the bird and its distribution in
Micronesia, are listed. The references are arranged as follows: (1)
citation to the original description, and (2) citations to names in
literature in the order of their first appearance. When a name is a pure
synonym, it may be recognized as such by the fact that the type locality
is given immediately following the citation. In compiling these
references the writer made use of the invaluable work by Wiglesworth
(1891) and of Utinomi's "Bibliographica Micronesia," made available
through the translation by Fisher (1947). The arrangement of the
families follows that of Peters (1931-1945) and Wetmore (1940).
Specimens examined are designated as to collection in which catalogued
by the following abbreviations: USNM, the United States National Museum;
AMNH, the American Museum of Natural History; MCZ, the Museum of
Comparative Zoölogy; and KMNH, the University of Kansas Museum of
Natural History. Average and extreme measurements of specimens are
usually listed in tables; unless otherwise indicated, measurements are
in millimeters, and are of adult specimens. The wings have been measured
by flattening them on a ruler. Weights are in grams. Unless otherwise
indicated, descriptions of the birds have been written by the author.
Descriptions of shore birds are not given; for these the reader may
refer to Mayr (1945a:28-47) where characters useful for identification
of the birds in the field also are given. The writer is especially
indebted to Dr. Ernst Mayr for making available the descriptions of
Micronesian birds made by Miss Cardine Bogert, especially those dealing
with color of the irides, feet, and bill. Color terms in quotation marks
refer to those in Ridgway (1912).
In dealing with insular forms the criterion of intergradation as
indicative of subspecies cannot be applied as it can in kinds of birds
on the mainland which have geographically continuous distributions.
Instead, degree of difference in combination with geographic position
plus other factors such as degree of variation in the geographic races
of the same species or a related species on continental areas are used
in deciding whether two closely related kinds are subspecies or full
species. Many kinds of birds in the islands are modified but little from
island to island (examples, _Rhipidura rufifrons_, _Aplonis opacus_,
_Ducula oceanica_, and _Myzomela cardinalis_), and can be treated as
subspecies. Others show much variability from island to island and it is
uncertain whether they should be treated as subspecies or as separate
species (examples, _Myiagra oceanica_, _Zosterops cinerea_, _Rukia_, and
possibly _Acrocephalus luscinia_). Decisions on generic status are
equally difficult to make. In many cases the experience and judgment of
the taxonomist may be the only criteria by which he can decide whether a
bird is different enough to be considered as a distinct genus. This
"human element" has caused some disagreement. Knowing whether the bird
is to be considered as a distinct genus or instead merely as a species
may not be as important as knowing its correct phylogenetic
relationship. The circumstance that variation in these insular birds is
in general less predictable than in mainland birds adds, I think, to the
pleasure inherent in the classification of the variations.
First, I thank Commodore Thomas N. Rivers (MC) USNR, then commanding
officer of NAMRU2, for the opportunity to join the Unit, for his
interested cooperation in seeing that the plans for field trips were
successful, and for his thoughtfulness in obtaining for me the orders
for duty at the United States National Museum subsequent to our field
investigations. Greatly appreciated also is the help rendered by my
former colleagues of NAMRU2, including Dr. David H. Johnson, Dr. George
W. Wharton, Dr. Aaron B. Hardcastle, Mr. Odis A. Muennik, Mr. L. P.
McElroy, Mr. Charles O. Davison, Mr. Merle H. Markley, Mr. Walter L.
Necker, Dr. Wilbur G. Downs, Dr. Bernard V. Travis, and Mr. E. W.
Coleman. Other personnel, then stationed in Micronesia, who contributed
data used in this report include: Dr. Joe T. Marshall, Jr., (who
generously loaned some of the specimens taken by him in Micronesia),
Dr. C. K. Dorsey, Dr. George Hensel, Mr. Tom Murray, Dr. Irwin O. Buss,
Mr. James O. Stevenson, Dr. Wilfred D. Crabb, Mr. Herbert Wallace, and
Dr. M. Dale Arvey. Authorities of the United States National Museum
provided generously for using the collections there, and I am especially
grateful to Dr. Alexander Wetmore, Dr. Herbert Friedman, and Mr. Herbert
G. Deignan for their cooperation and assistance. Doctor Wetmore kindly
made available many of the birds collected at Bikini during the atomic
bomb experiments. Dr. Robert Cushman Murphy, Dr. Ernst Mayr, and Dr.
Dean Amadon of the American Museum of Natural History made available the
collections in their charge. Doctor Murphy allowed me to examine some of
the heretofore unstudied collections of sea birds of the Whitney South
Sea Expedition. Doctor Mayr generously helped me with taxonomic and
evolutionary problems and made available to me some of his own
unpublished taxonomic notes, the unpublished field accounts of Mr.
William F. Coultas and a partly completed manuscript on the birds of
Micronesia by Miss Cardine Bogert. Mr. James L. Peters generously loaned
specimens from the Museum of Comparative Zoölogy. The use of unpublished
field notes made by Mr. Larry P. Richards at Ponapé and Truk in 1947 and
1948 is also gratefully acknowledged. I am grateful also to my
colleagues at the Museum of Natural History of the University of Kansas
and would single out for special mention Dr. E. Raymond Hall who gave
critical assistance with the manuscript, Drs. Edward H. Taylor and
Herbert B. Hungerford who made helpful suggestions, and Mrs. Virginia
Cassell Unruh who drew the distributional maps.
ACCOUNTS OF THE KINDS OF BIRDS OF MICRONESIA
=Diomedea nigripes= Audubon
Black-footed Albatross
_Diomedea nigripes_ Audubon, Ornith. Biog., 5, 1839, p. 327. (Type
locality, Pacific Ocean, lat. 30°44´N., long. 146°W.)
_Diomedea fuliginosa_ Oustalet, Le Nat., 1889, p. 261 (Mariannes).
_Diomedea nigripes_ Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris
(3), 8, 1896, p. 51 (Agrigan); Hartert, Novit. Zool., 5, 1898, p.
68 (Marianne); Seale, Occ. Papers Bernice P. Bishop Mus. 1, 1901,
p. 22 (Marianas); Safford, Osprey, 1902, p. 70 (Mariannes);
_idem_, The Plant World, 7, 1904, p. 268 (Guam?); Kuroda, in
Momiyama, Birds Micronesia, 1922, p. 32 (Marriane); Peters,
Check-list Birds World, 1, 1931, p. 43 (Marshalls); Hand-list
Japanese Birds, rev., 1932, p. 188 (Marianas); Hand-list Japanese
Birds, 3rd ed., 1942, p. 210 (Marianas); Mayr, Birds Southwest
Pacific, 1945, p. 5 (Marshalls).
_Geographic range._--North Pacific Ocean. Breeds on islands
northwest of Hawaii. In Micronesia: Mariana Islands--Agrigan.
_Characters._--A large oceanic bird with sooty-brown coloration;
darker on nape, wings and tail; lighter on forehead, sides of head,
and abdomen; area surrounding bill whitish; tail whitish at base;
bill dark reddish-brown; feet black.
_Remarks._--This albatross has been recorded from waters near the
Mariana Islands. Quoy and Gaimard (1824:145) observed "albatross"
between the Mariana and the Hawaiian Islands. The only actual specimens
obtained from the islands were reported on by Oustalet (1896:51). These
were eight Black-footed Albatrosses which were taken on the coast of
Agrigan by Marche in December, 1888, and January, 1889. Oustalet gives
the following measurements: total length, 680-785; wing, 485-525; tail,
180-225; tarsus, 80-90; culmen, 108-125. The specimens are apparently in
the Paris Museum.
Peters (1931:43) lists the Marshall Islands as part of the range of _D.
nigripes_.
In the period of the late war Gleise (1945:221) observed eight
Short-tailed Albatrosses (_D. albatrus_ Pallas) "off Saipan." Specimens
of _D. albatrus_ have not been taken in Micronesia. According to Austin
(1948b:32) this albatross "is now virtually extinct," and this record
may be questioned.
=Puffinus pacificus chlororhynchus= Lesson
Wedge-tailed Shearwater
_Puffinus chlororhynchus_ Lesson, Traité d'Ornith., 8, 1931, p.
613. (Type is from Shark's Bay, West Australia.)
_Puffinus sphenurus_ Schmeltz and Krause, Ethnogr. Abth. Mus.
Godeffroy, 1881, p. 299 (Mortlock).
_Puffinus chlororhynchus_ Wiglesworth, Abhandl. und Ber. Zool.
Mus. Dresden, no. 6, 1890-1891 (1891), p. 80 (Luganor?); Godman,
Monogr. Petrels, pt. 2, 1908, p. 88 (Carolines); Kuroda, in
Momiyama, Birds Micronesia, 1922, p. 33 (Luganor or Ruk?).
_Puffinus pacificus chlororhynchus_ Hand-list Japanese Birds,
rev., 1932, p. 187 (Lukunor or Truk?, Kusaie); Hand-list Japanese
Birds, 3d ed., 1942, p. 209 (Lukunor or Truk?, Kusaie).
_Geographic range._--Breeds at the Seychelles, Australia, Lord
Howe, Norfolk, and other islands in the Australian area. Ranges
throughout most of the warmer parts of the Indian and Pacific
oceans. In Micronesia: Mariana Islands--Guam; Caroline
Islands--Lukunor or Truk?, Kusaie.
_Characters._--A large shearwater with long wedge-shaped tail;
upper parts sooty-brown with crown, neck, and wings darker and
forehead paler; under parts paler than upper parts; bill dark;
feet flesh-colored.
_Remarks._--This shearwater was taken by Kubary either at Lukunor or at
Truk in the Caroline Islands. At a later date, apparently between 1922
and 1932, the Japanese recorded the bird at Kusaie. In using this
subspecific name, I am following the Hand-list of Japanese Birds
(Hachisuka _et al._, 1932:187).
At Guam on August 10, 1931, Coultas obtained a male shearwater, which is
tentatively placed in this subspecies. Its measurements are as follows:
wing, 290; tail, 128; exposed culmen, 39; tarsus, 47. Coultas (field
notes) writes that he was told by natives that petrels nest and roost on
the high cliffs behind the city of Agaña on Guam. At sea south of the
eastern Caroline islands, Coultas obtained five other birds which appear
to be the same as the bird from Guam. All specimens are in the
collections of the American Museum of Natural History.
=Puffinus pacificus cuneatus= Salvin
Wedge-tailed Shearwater
_Puffinus cuneatus_ Salvin, Ibis, 1888, p. 353. (Type locality,
Krusenstern Island==Ailuk, Marshall Islands, _fide_ Fisher, Auk,
63, 1946, pp. 587-588.)
_Puffinus cuneatus_ Wiglesworth, Abhandl. und Ber. Zool. Mus.
Dresden, no. 6, 1890-1891 (1891), p. 80 (Krusenstern); Salvin,
Cat. Birds British Mus., 25, 1896, p. 371 (Krusenstern); Godman,
Monogr. Petrels, pt. 2, 1908, p. 76 (Marshalls).
_Puffinus pacificus cuneatus_ Mathews, Birds Australia, 2, 1912,
p. 84 (Marshall Group); Peters, Check-list Birds World, 1, 1931,
pp. 55-56 (Krusenstern); Hand-list Japanese Birds, 3d ed., 1942,
p. 209 (Krusenstern); Fisher, Auk, 63, 1946, pp. 587-588 (Ailuk).
_Thyellodroma cuneata cuneata_ Mathews and Iredale, Ibis, 1915, p.
597 (Krusenstern); Mathews, Syst. Avium Australasianarum, 1, 1927,
p. 113 (Marshall Group).
_Thyellodroma cuneata_ Oberholser, Auk, 34, 1917, p. 474
(Krusenstern).
_Thyellodroma pacificia cuneata_ Mathews, Novit. Zool., 39, 1934,
p. 186 (Caroline Islands).
_Geographic range._--Pescadores east to the Hawaiian Islands and
south to eastern Micronesia. In Micronesia: Marshall
Islands--Ailuk.
_Remarks._--Osbert Salvin received two specimens of this shearwater from
H. J. Snow, who got them at the Krusenstern Islands in 1883. In
describing them, Salvin (1888:353) comments that the locality is
seemingly in the Marshall Islands at approximately 10°17´ N. and 190° W.
This locality was confusing to Seebohm (1891:191) who thought it was
between the Hawaiians and the Marshalls, while Hartert (1926:352)
decided it was really Krusenstern Rocks in the Hawaiian Group. To clear
the matter up, Fisher (1946:587-588) writes that Salvin was correct and
suggests that the name of the island should be the better established
one, Ailuk, rather than the little used one, Krusenstern.
_P. p. cuneatus_ resembles _P. p. chlororhynchus_ but is whiter on the
underparts, especially the breast. These two subspecies are inseparable
according to the twenty-fourth supplement to the American
Ornithologists' Union Check-list of North American Birds (Auk, vol. 66,
1949:281).
=Puffinus tenuirostris= (Temminck)
Short-tailed Shearwater
_Procellaria tenuirostris_ Temminck, Pl. Col., livr. 99, 1835, text
to pl. 587. (Type locality, Seas north of Japan and shores of
Korea.)
_Puffinus tenuirostris tenuirostris_ Bryan, Guam Rec., vol. 13,
no. 2, 1936, p. 15 (Guam).
_Puffinus tenuirostris_ Yamashina, Tori, 10, 1940, p. 677
(Kinajon, Marshall Islands); Hand-list Japanese Birds, 3d ed.,
1942, p. 210 (Kinajon, Marshall Islands).
_Geographic range._--Breeds in Tasmania, southeastern Australia,
islands in Bass Straits, and Bounty Islands. Ranges north to the
Bering Sea. In Micronesia: Mariana Islands--Guam?; Marshall
Islands--Kinajon.
_Character._--A rather large shearwater with short, rounded tail;
upper parts sooty brown; underparts paler and more grayish than
back; throat may be occasionally whitish; bill lead-gray; feet
grayish, browner on outer side.
_Remarks._--On migration this shearwater probably reaches most parts of
Micronesia. It has been recently recorded by the Japanese at Kinajon in
the Marshall Islands. Bryan (1936:15) includes this species as a "chance
arrival" in his list of the birds of Guam.
=Puffinus nativitatis= Streets
Christmas Shearwater
_Puffinus (Nectris) nativitatis_ Streets, Bull. U. S. Nat. Mus., 7,
1877, p. 29. (Type locality, Christmas Island, Pacific Ocean.)
_Puffinus nativitatis_ Salvin, Cat. Birds British Mus., 25, 1896,
p. 389 (Krusenstern); Lister, Proc. Zool. Soc. London, 1891, pp.
295-300 (Krusenstern); Godman, Monogr. Petrels, pt. 3, 1908, p.
153 (Marshalls).
_Geographic range._--Breeds at Wake and Laysan Islands south to
Christmas, Phoenix, Marquesas, Tuamotu, and Austral Islands. In
Micronesia: Marshall Islands--Ailuk.
_Characters._--Upper parts chocolate brown; underparts resemble
upper parts but throat may be slightly grayer; bill and feet
black. _P. nativitatis_ resembles _P. pacificus_ but is similar
with black feet.
_Remarks._--The only specimens of this bird known from Micronesia, are
those taken in the spring of 1883 by H. J. Snow at Krusenstern (Ailuk)
in the Marshall Islands. For two birds from this island in the
collections of the British Museum, Godman (1908:154) gives the following
measurements: wing, 9.6 and 10.0; tail, 3.35 and 3.4; culmen, 1.15 and
1.2; tarsus, 1.7 and 1.8; middle toe and claw, 2.0 and 2.1.
=Puffinus lherminieri dichrous= Finsch and Hartlaub
Dusky Shearwater
_Puffinus dichrous_ Finsch and Hartlaub, Fauna Centralpolynesiens,
1867, p. 244. (Type locality, McKean Island, Phoenix Group.)
_Puffinus dichrous_ Hartlaub and Finsch, Proc. Zool. Soc. London,
1872, pp. 90, 108 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875,
pp. 6, 44 (Palau).
_Puffinus opisthomelas_ var. _minor_ Hartlaub, Proc. Zool. Soc.
London, 1867 (1868), p. 832 (Type locality, Pelew); Finsch, Journ.
f. Ornith., 1872, p. 57 (Pelew).
_Puffinus opisthomelas_ Hartlaub and Finsch, Proc. Zool. Soc. London,
1868, pp. 9, 118 (Pelew); Finsch, Journ. f. Ornith., 1870, p. 371
(Pelew).
_Puffinus tenebrosus_ Pelzeln, Ibis, 1873, p. 47, fig. 1 (Type
locality, unknown==Pelew Islands, _ex_ Mathews); Oustalet, Nouv.
Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 55 (Rota); Hartert,
Novit. Zool., 5, 1898, p. 69 (Marianne); Seale, Occ. Papers Bernice
P. Bishop Mus., 1, 1901, p. 23 (Marianas?); Safford, The Plant World,
7, 1904, p. 268 (Guam).
_Puffinus obscurus_ Finsch, Journ. Mus. Godeffroy, 12, 1876, pp.
18, 40 (Ponapé, Palau); _idem_, Proc. Zool. Soc. London, 1877, p.
786 (Palau); _idem_, Proc. Zool. Soc. London, 1877 (1878), p. 782
(Ponapé); _idem_, Journ. f. Ornith., 1880, pp. 295, 309 (Ponapé,
Kuschai); _idem_, Proc. Zool. Soc. London, 1880, p. 577 (Ruk);
_idem_, Ibis, 1881, p. 109 (Kuschai); _idem_, Ibis, 1881, pp. 113,
115 (Ponapé); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy,
1881, p. 353 (Ruk); Salvin, Ibis, 1888, p. 357 (Pelew);
Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891
(1891), p. 79 (Ruk, Ponapé, Pelew); Oustalet, Nouv. Arch. Mus.
Hist. Nat. Paris, (3), 8, 1896, p. 54 (Saypan, Palaos); Salvin,
Cat. Birds British Mus., 25, 1896, p. 382 (Carolines, Pelews);
Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne); Seale, Occ.
Papers Bernice P. Bishop Mus., 1, 1901, p. 23 (Marianas?); Safford,
Osprey, 1902, p. 70 (Marianas); Dubois, Syn. Avium, 2, 1904, p.
1031 (Pelew, Carolines); Godman, Monogr. Petrels, pt. 2, 1908, pp.
126, 127 (Pelew, Ruk, Ponapé).
_Puffinus obscurus obscurus_ Hartert, Novit. Zool., 7, 1900, p. 10
(Ruk); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 32 (Saipan,
Ruk, Ponapé, Pelew).
_Puffinus lherminieri minor_ Mathews, Birds Australia, 2, 1912, p.
70 (Pelew, Carolines).
_Puffinus assimilis minor_ Mathews, Syst. Avium Australasianarum,
1, 1927, p. 111 (Pelew).
_Puffinus lherminieri dichrous_ Murphy, Amer. Mus. Novit., no.
276, 1927, p. 10 (Pelews, Carolines); Peters, Check-list Birds
World, 1, 1931, p. 60 (Pelew); Yamashina, Tori, 7, 1932, p. 408
(Arakabesan); Hand-list Japanese Birds, rev., 1932, p. 188
(Saipan, Truk, Ponapé, Palaus); Hand-list Japanese Birds, 3rd ed.,
1942, p. 209 (Saipan, Truk, Ponapé, Palau); Mayr, Birds Southwest
Pacific, 1945, p. 10 (Carolines, Palaus); Baker, Smithson. Misc.
Coll., vol. 107, no. 15, 1948, p. 37 (Palau).
_Alphapuffinus lherminieri minor_ Mathews, Novit. Zool., 39, 1934,
p. 182 (Pelew Islands).
_Puffinus obscura_ Bryan, Guam Rec., vol. 13, No. 2, 1936, p. 15
(Guam).
_Geographic range._--Known from Phoenix, Nauru, Micronesia, and
south to the Samoan, Society, Tuamotu, and Marquesas islands. In
Micronesia: Mariana Islands--Guam, Rota, Saipan; Palau
Islands--Babelthuap, Koror, Arakabesan; Caroline Islands--Truk,
Ponapé, Kusaie.
_Characters._--A small shearwater with upper parts sooty-black;
under parts white except for sides of breast grayish and under
tail-coverts blackish; bill blackish; feet yellowish, outer toe
black.
_Measurements._--Measurements of 17 adult birds (9 males, 7
females, 1 unsexed) from Micronesia (Palau, Truk, Ponapé, Kusaie)
and 10 adult birds (6 males, 4 females) from the Phoenix Group
(Enderbury, Canton) are listed in table 14.
TABLE 14. MEASUREMENTS OF _Puffinus lherminieri dichrous_
===========+=============+============+==============+==============
LOCALITY | Wing | Tail |Exposed culmen| Tarsus
-----------+-------------+------------+--------------+--------------
Micronesia |203 (197-211)|83.6 (77-89)| 27.9 (26-30) |38.5 (37.5-40)
Phoenix |197 (193-203)|82.2 (79-85)| 26.3 (25-28) |37.2 (36-39)
-----------+-------------+------------+--------------+--------------
_Specimens examined._--Total number, 72 (44 males, 19 females, 9
unsexed), as follows: Palau Islands, AMNH--exact locality not
given, 64 (Oct., Nov., Dec.); Caroline Islands, AMNH--Truk, 4 (June
15, 16)--Ponapé, 3 (undated)--Kusaie, 1 (April 25).
_Nesting._--The Dusky Shearwater in Micronesia nests in holes on
high, and usually isolated, coral cliffs. Owston's collectors,
according to Hartert (1900:10), found a nest with one egg at Truk
on June 16. The nest was in a hole four feet deep in the side of a
cliff. The egg is white and measures 42 × 35. Yamashina (1932a:408)
records the taking of one egg at Arakabesan, Palau Islands, on May
26. Coultas (field notes) gives an interesting account of nesting
activities of this shearwater at the Palau Islands. He found the
bird nesting on small islands of the group from October to
December, 1931; however, he states that the natives told him that
the bird nests throughout the year. Land crabs and shearwaters were
often found together in the same burrow. Apparently the adult birds
did not remain in the burrow with the young during the day. At
Kusaie, Coultas was told by the natives that the adult birds were
caught by tying the mandibles of the young together. When the
parent birds approached and hovered over the young birds expecting
their mouths to open, the natives had the opportunity to strike
them down with clubs. Coultas collected six downy nestlings at
Palau in November and December.
_Remarks._--The first published account of this shearwater in Micronesia
was apparently by Kittlitz (1858, pt. 1:358) when he recorded his
"Schwärzlicher Sturmvogel" at Kusaie, according to Wiglesworth
(1891a:79). Finsch (1875:44 and 1881b:113, 115) studied specimens taken
by Tetens, Heinsohn, and Kubary at the Palau Islands and those taken by
Kubary at Ponapé. Earlier, Hartlaub (1868:832) used some of these
specimens from the Palau Islands to describe his _Puffinus opisthomelas_
var. _minor_, which was destined to be placed in synonymy (Murphy,
1927:10). Oustalet (1896:54, 55) recorded specimens taken by Marche at
Saipan in May, 1887, and at Rota in July, 1888. Oustalet referred to
them as _P. obscuras_ and _P. tenebrosus_, respectively. T. W. Gulick
obtained undated skins at Ponapé. Hartert (1900:10) reported on
specimens taken by Owston's collectors at Truk. In 1931, Coultas with
the Whitney South Sea Expedition took one shearwater at Kusaie and a
series of 64 skins at the Palau Islands. He failed to find birds at
Ponapé and wrote that their scarcity there may have been due to
persistent hunting of them by the inhabitants of the island. The NAMRU2
party obtained no information concerning the birds at Guam, Rota, or
Truk, but at the Palau Islands observed shearwaters at sea approximately
6 miles east of Babelthuap Island on September 2, 1945.
Murphy (1927:6-15) revised the shearwaters of the _Puffinus lherminieri_
group, and recognized several subspecies. _P. l. dichrous_ was assigned
a range consisting of Micronesia, the Phoenix Islands, and Nauru Island.
The breeding range of _P. l. polynesiae_ was given as the Samoan,
Society, Tuamotu and Marquesas islands. Color differences between the
two subspecies are very slight, and he separated them on the basis of
the length of the exposed culmen as follows: _P. l. dichrous_ 22.6-27
(26) in _P. l. polynesiae_ 25.5-30 (28.9). In other measurements they
closely resembled one another. At the time of his study, Murphy did not
have the shearwaters from Micronesia collected by Coultas and actually
did not have a large series from these islands. On studying this new
material, I find the length of the exposed culmen of 17 adult birds from
Micronesia (including 12 from the Palaus) to be 26-30 (27.9). In
comparison with Murphy's findings, my measurements of Micronesian birds
fall almost midway between the measurements which he recorded as
characteristic of _P. l. dichrous_ (from the Phoenix Islands) and _P. l.
polynesiae_. The intermediate position of the measurements of the
Micronesian birds, together with the absence of other distinguishing
characters, suggests that these shearwaters belong to only one
subspecies which consists of a group of isolated and variable
populations. Unless the old specific name, _obscuras_ of Gmelin, is
revived, the name for the entire group in Micronesia and Polynesia would
be _P. l. dichrous_. I agree with Murphy that the Bonin form, _P. l.
bannermani_, is a well-defined subspecies.
=Pterodroma rostrata rostrata= (Peale)
Tahiti Petrel
_Procellaria rostrata_ Peale, U. S. Expl. Exp., 8, 1848, p. 296.
(Type locality, Mountains about 6,000 feet on Tahiti, Society
Islands.)
_Procellaria desolata_ Pucheran, Voy. Pôle Sud, 3, 1853, p. 138
(des îles Carolines); Hartlaub, Journ. f. Ornith., 1854, p. 168
(Carolinen).
_Procellaria (Aestrelata) desolata_ Gray, Cat. Birds Trop. Is.
Pacific Ocean, 1859, p. 55 (Caroline Islands).
_Oestrelata rostrata_ Wiglesworth, Abhandl. und Ber. Zool. Mus.
Dresden, no. 6, 1890-1891 (1891), p. 82 (Caroline Is.); Godman,
Monogr. Petrels, pt. 3, 1908, p. 190 (Caroline Is.).
_Pterodroma rostrata_ Kuroda, in Momiyama, Birds Micronesia, 1922,
p. 33 (Carolines).
_Pterodroma rostrata_ subsp. (?) Hand-list Japanese Birds, rev.,
1932, p. 188 (Carolines); Hand-list Japanese Birds, 3d ed., 1942,
p. 210 (Carolines).
_Geographic range._--Known to breed on the Society and Marquesas
Islands. In Micronesia: Caroline Islands--exact locality unknown.
_Characters._--A large petrel with blackish-brown plumage except
for belly and under tail-coverts white and throat, upper breast
and flanks pale brown; bill black; legs yellowish; feet black.
This oceanic bird differs from other petrels and shearwaters of
Micronesia by the presence of a white abdomen in contrast with
dark plumage on upper parts, throat, and breast.
_Remarks._--A petrel which is referred to this subspecies has been taken
once in Micronesia, by Hombron and Jacquinot in the Caroline Islands. It
may be pointed out that the subspecies _P. r. becki_ Murphy is known
from the sea east of the Bismarck Archipelago and might range into
Micronesian waters.
=Pterodroma hypoleuca hypoleuca= Salvin
Stout-billed Gadfly Petrel
_Oestrelata hypoleuca_ Salvin, Ibis, 1888, p. 359. (Type locality,
Krusenstern Island = Ailuk, Marshall Islands, _fide_ Fisher, Auk.,
63, 1946, pp. 587-588).
_Oestrelata hypoleuca_ Salvin, Cat. Birds British Mus., 25, 1896,
p. 409 (Krusenstern); Godman, Monogr. Petrels, pt. 3, 1908, p. 212
(Krusenstern).
_Cookilaria hypoleuca hypoleuca_ Mathews, Syst. Avium
Australasianarum, 1, 1927, p. 122, (Marshall Group).
_Pterodroma leucoptera hypoleuca_ Hand-list Japanese Birds, rev.,
1932, p. 188 (Marshalls); Hand-list Japanese Birds, 3d ed., 1942,
p. 210 (Krusenstern); Fisher, Auk, 63, 1946, pp. 387-388 (Ailuk).
_Pterodroma hypoleuca hypoleuca_ Mayr, Birds Southwest Pacific,
1945, p. 11 (Micronesia).
_Geographic range._--Ranges from the Bonins east to the Hawaiians
and south to Micronesia. In Micronesia: Marshall Islands--Ailuk.
_Characters._--Upper parts grayish except for forehead whitish,
crown and nape sooty-black; underparts whitish except for sides of
breast sooty-black; legs and feet flesh color except for tips of
toes and webs which are black.
_Remarks._--In Micronesia, this petrel is known only from the type
locality, Krusenstern or Ailuk, Marshall Islands. Fisher (1946: 587-588)
has corrected the confusion regarding the exact position of this type
locality.
=Phaëthon aethereus mesonauta= Peters
Red-billed Tropic-bird
_Phaëthon aethereus mesonauta_ Peters, Occ. Papers Boston Soc. Nat.
Hist., 5, 1930, p. 261. (Type locality, Swan Key, Almirante Bay,
Panama.)
_Phaeton aethereus_ Finsch, Ibis, 1880, pp. 329, 333, (Ratak
Chain, Marshalls); _idem_, Journ. f. Ornith., 1880, p. 310
(Kuschai); _idem_, Ibis, 1881, p. 109 (Kuschai); Wiglesworth,
Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p.
73 (Kushai, Marshalls); Ogilvie-Grant, Cat. Birds British Mus. 26,
1898, p. 457 (Kushai, Marshalls); Schnee, Zool. Jahrbücher, 20,
1904, p. 390 (Marschall Inseln); Kuroda, in Momiyama, Birds
Micronesia, 1922, p. 34 (Kusaie, Marshall Islands).
_Phaethon aethereus [?mesonauta]_ Hand-list Japanese Birds, rev.,
1932, p. 187 (Kusaie, Marshalls); Hand-list Japanese Birds, 3d
ed., 1942, p. 208 (Kusaie, Marshall Islands).
_Geographic range._--Tropical parts of Atlantic and eastern Pacific
from Cape Verde Islands west to Panama and Galapagos Islands. In
Micronesia: Caroline Islands--Kusaie; Marshall Islands--Ratak
Chain.
_Characters._--Adult: A large, white sea bird with a long white
tail; dorsal surface marked with blackish, transverse
vermiculations; bill red; tarsus and foot flesh-colored with a
yellowish hue, with plantar surface grayish. Immature: Resembles
adults but dark transverse bars are broader; crown blacker; bill
yellow.
_Remarks._--No specimens have been examined. The Red-billed Tropic-bird
is placed in the list of birds known from Micronesia on the basis of
two observations by the German ornithologist, Otto Finsch. It has not
been reported since his time, and may be considered as an unusual record
for the area. I am following the Hand-list of Japanese Birds (Hachisuka
_et al._, 1942:208) in assigning the bird to the subspecies, _P. a.
mesonauta_.
=Phaëthon rubricauda rothschildi= (Mathews)
Red-tailed Tropic Bird
_Scaeophaethon rubricauda rothschildi_ Mathews, Birds Australia, 4,
1915, p. 303. (Type locality, Laysan and Niihau.)
_Phaeton rubricaudus_ Finsch, Journ. f. Ornith., 1880, p. 296
(Carolines); _idem_, Ibis, 1881, p. 115 (Ponapé).
_Phaeton rubricauda_ Finsch, Proc. Zool. Soc. London, 1880, p. 577
(Ruk); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6,
1890-1891 (1891), p. 73 (Ruk, Ponapé, Marshalls).
_Phaeton rubricauda_ Ogilvie-Grant, Cat. Birds British Mus., 26,
1898, p. 451 (Caroline Islands); Hartert, Novit. Zool., 7, 1900,
p. 11 (Ruk); Hand-list Japanese Birds, rev., 1932, p. 187 (Pagan,
Truk, Ponapé, Marshalls).
_Scaeophaethon rubricauda_ Kuroda, in Momiyama, Birds Micronesia,
1922, p. 34 (Mariannes, Ruk, Ponapé, Marshalls).
_Phaethon rubricauda rothschildi_ Yamashina, Tori, 7, 1932, p. 406
(Pagan); _idem_, Tori, 10, 1940, p. 676 (Maug).
_Phaethon rubricaudus rothschildi_ Hand-list Japanese Birds, 3d
ed., 1942, p. 209 (Maug, Pagan, Truk, Ponapé, Marshalls).
_Geographic range._--Bonin and Hawaiian islands south to
Micronesia. In Micronesia: Mariana Islands--Maug, Pagan; Caroline
Islands--Truk, Ponapé; Marshall Islands--exact locality unknown.
_Characters._--Adult: Long-tailed sea bird white with pinkish tint
except for black lores and eye streak; black shafts on feathers of
secondaries, flanks, and tail coverts; black bases on feathers of
head; central tail feathers elongate with black shafts and bright
red webs; bill orange-red with black nasal streak; tarsus and foot
bluish-yellow, distal part blackish. Immature: Resembles adult but
barred with black above; bill blackish.
_Measurements._--Yamashina (1940:676) lists the measurements for
seven adult birds from Maug in the northern Marianas as wing
304-319 and exposed culmen 55-62.
_Nesting._--Yamashina (1932a:406) reports the taking of one egg at
Pagan in the Marianas on February 15, 1931.
_Remarks._--The Red-tailed Tropic Bird has been recorded from the
Mariana, Caroline, and Marshall Islands. On the basis of our present
knowledge it appears to be uncommon in most of Micronesia and may be
established as a resident bird only in the northern Marianas, as shown
by Yamashina (1932a:406 and 1940:676), Coultas obtained an immature male
at 3° N and 158° E, which is at a point in the ocean south of the
eastern Carolines. Possibly this bird and others obtained in the
Carolines are representatives of the subspecies, _P. r. melanorhynchos_
Gmelin, which is known from the Palmerston, Society and Turtle islands.
=Phaëthon lepturus dorotheae= Mathews
White-tailed Tropic Bird
_Phoethon lepturus dorotheae_ Mathews, Austr. Avium. Rec., 2, 1913,
p. 7. (Type locality, Queensland.)
_Phaeton candidus_ Kittlitiz, Denkw. Reise russ. Amer. Micron. und
Kamchat., 1, 1858, p. 382 (Ualan); Hartlaub and Finsch, Proc.
Zool. Soc. London, 1868, pp. 9, 118 (Pelew); Finsch, Journ. f.
Ornith., 1872, p. 57 (Pelew); Hartlaub and Finsch, Proc. Zool.
Soc. London, 1872, pp. 90, 114 (Pelew, Ualan); Finsch, Journ. Mus.
Godeffroy, 1875, pp. 6, 47 (Palau); _idem_, Proc. Zool. Soc.
London, 1877 (1878), p. 782 (Ponapé); _idem_, Journ. f. Ornith.,
1880, pp. 296, 309 (Ponapé, Kuschai); _idem_, Proc. Zool. Soc.
London, 1880, p. 577 (Ruk); Schmeltz and Krause, Ethnogr. Abth.
Mus., Godeffroy, 1881, pp. 281, 299, 330, 353 (Ponapé, Mortlock,
Nukuor, Ruk); Finsch, Mitth. Ornith. Ver. Wien, 1884, p. 52
(Kuschai); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no.
6, 1890-1891 (1891), p. 73 (Pelew, Ruk, Luganor, Nukuor, Ponapé,
Ualan, Marshalls); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris,
(3), 8, 1896, p. 62 (Agrigan, Palaos, Ruk, Kushai, Marshalls);
Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne).
_Phaeton flavirostris_ Finsch, Ibis, 1880, pp. 329, 333 (Ratak
Chain); _idem_, Ibis, 1881, pp. 105, 109, 115 (Kuschai, Ponapé).
_Phaethon candidus_ Salvadori, Ornith. Papuasia, 3, 1882, p. 426
(Pelews, Carolines, Marshalls); Seale, Occ. Papers Bernice P.
Bishop Mus., 1, 1901, p. 23 (Agrigan); Safford, Osprey, 1902, p.
70 (Mariannes); Takatsukasa and Kuroda, Tori, 1, 1915, p. 50
(Pelew, Ponapé); Uchida, Annot. Zool. Japon., 9, 1918, pp. 489,
492 (Palau).
_Phaëthon lepturus_ Ogilvie-Grant, Cat. Birds British Mus., 26,
1898, p. 453 (Pelew, Carolines, Marshalls); Hartert, Novit. Zool.,
7, 1900, p. 10 (Ruk); Safford, The Plant World, 7, 1904, p. 268
(near Guam); _idem_, Contr. U. S. Nat. Herb., 9 1905, p. 80
(northern Marianas); Mayr, Birds Southwest Pacific, 1945, p. 17
(Palau); Strophlet, Auk, 63, 1946, p. 535 (Guam); Borror, Auk, 64,
1947, p. 416 (Agrihan); Stott, Auk, 64, 1947, p. 524 (Saipan).
_Phaeton lepturus_ Schnee, Zool. Jahrbücher, 20, 1904, p. 390
(Marschall Inseln).
_Leptophaethon lepturus dorothea_ Mathews, Birds Australia, 4,
1915, p. 309 (Pelew).
_Phaethan lepturus_ Cox, Island of Guam, 1917, p. 22 (northern
Marianas).
_Leptophaethon lepturus lepturus_ Kuroda, in Momiyama, Birds
Micronesia, 1922, p. 33 (Agrigan, Saipan, Pelew, Ruk, Luganor,
Nukuor, Ponapé, Kusaie, Marshalls).
_Phaethon lepturus dorotheae_ Yamashina, Tori, 7, 1932, p. 407
(Ponapé); Hand-list Japanese Birds, rev., 1932, p. 187 (Agrigan,
Pagan, Saipan, Agiguan, Palaus, Truk, Luganor, Nukuor, Ponapé,
Kusaie, Marshalls); Hand-list Japanese Birds, 3d ed., 1942, p. 209
(Agrigan, Pagan, Saipan, Agiguan, Babelthuap, Koror, Urukthapel,
Angaur, Unusuto, Truk, Luganor, Nukuor, Ponapé, Kusaie, Namorik);
Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 38 (Guam,
Peleliu, Ulithi, Truk).
_Geographic range._--Islands in the southwestern Pacific area. In
Micronesia: Mariana Islands--Agrigan, Pagan, Saipan, Agiguan, Rota,
Guam; Palau Islands--Babelthuap, Koror, Urukthapel, Peleliu,
Anguar, Unusuto; Caroline Islands Truk, Ulithi, Luganor, Nukuor,
Ponapé, Kusaie; Marshall Islands--Namorik.
_Characters._--Adult: White often with pinkish shade but lores and
eye streak black; feathers of head, flanks and under tail-coverts
with bases black; black on outer and subterminal part of inner
webbing of primaries; black, subterminal coloring on scapulars and
secondaries; black on shafts of elongated tail plumes; bill horn
yellow, dark basally; tarsus dark yellow; feet blackish.
Immature: Resembles adult but upper parts barred with black, bill
black on terminal part.
_Measurements._--Measurements of adult birds from Micronesia are
given in table 15.
_Weights._--The NAMRU2 party recorded weights of five adult males
from Guam as 294 (267-321) grams.
TABLE 15. MEASUREMENTS OF _Phaëthon lepturus_ FROM MICRONESIA
---------------------------+-----+---------+--------+---------+-------
| | | | Exposed |
| No. | Wing | Tail | culmen | Tarsus
---------------------------+-----+---------+--------+---------+-------
Marianas: Asuncion, Guam | 6 | 264 | 107 | 47 | 21
| | 256-287 | 97-117 | 44-50 | 20-21
| | | | |
Palaus: Peleliu | 11 | 257 | 108 | 45 | 21
| | 242-270 | 98-122 | 40-49 | 19-21
| | | | |
Carolines: Ponapé, Kusaie | 11 | 261 | 105 | 47 | 21
| | 252-271 | 97-114 | 44-49 | 21-22
+-----+---------+--------+---------+-------
Total: Micronesia | 28 | 260 | 107 | 46 | 21
| | 242-287 | 97-122 | 40-50 | 19-22
---------------------------+-----+---------+--------+---------+-------
_Specimens examined._--Total number, 37 (22 males, 10 females, 5
unsexed), as follows: Mariana Islands, USNM--Guam, 5 (June 11, July
21); AMNH--Asuncion, 1 (June?); Palau Islands, USNM--Peleliu, 5
(Aug. 29, 31, Sept. 5, 6); AMNH--exact locality not given, 7 (Oct.
13, 26, Nov. 15, 23, Dec. 18); Caroline Islands, AMNH--Ponapé, 9
(Dec. 8, 9, undated)--Kusaie, 10 (March 1-8, April).
_Nesting._--The NAMRU2 party observed nests of the White-tailed
Tropic Bird at Peleliu in August and September, 1945. Several
nests were seen in hollows of the Australian pine (_Casuarina
equisetifolia_) between 20 and 30 feet above the ground. Birds
could be seen in the nest hollows because the plumes of their long
tail usually extended well out of the entrance. One nest was found
in a dead tree in a battle-cleared area; others were observed in
jungle habitat. Coultas observed nesting at Ponapé between
November 1 and December 30, 1930, and found nests in the tops of
trees and in hollow trees; a few were observed in holes in cliffs.
Yamashina (1932a:407) records the taking of one egg at Ponapé on
August 18, 1931. At Guam the NAMRU2 party found birds along the
high cliffs which edge the beach. There was no evidence that they
were nesting from May to July; nevertheless males taken in June
had enlarged gonads. The bird is known to breed at Namorik in the
Marshall Islands, according to the Hand-list of Japanese Birds
(Hachisuka _et al._, 1942:209).
_Food habits._--The NAMRU2 party found small fish in the stomachs
of these birds taken at Peleliu.
_Parasites._--Uchida (1918:489, 492) records the bird lice
(Mallophaga), _Colpocephalum epiphanes_ and _Menopon eulasius_,
from the White-tailed Tropic Bird from Palau.
_Remarks._--Birds taken in Micronesia differ only slightly from those
from other areas in Oceania. Within Micronesia (see table 15) the birds
from the Palaus have the shortest wing and shortest exposed culmen.
The White-tailed Tropic Bird appears more numerously in western and
northern Micronesia than in the Marshall Islands. This distribution may
be correlated with a preference for the "high" islands; especially those
which have rocky cliffs, including Guam, Rota, Peleliu, Angaur, and
Truk. Reports were received in 1945 that the birds were only
infrequently seen at Ulithi, a low atoll. Stott (1947:524) observed
birds flying into rocky crevices at Saipan on December 18. Gleise
(1945:221) also recorded the bird in the vicinity of Saipan. Borror
(1947:416) reports seeing birds at Agrigan on July 29, August 5 and 6,
1945. Coultas (field notes) found tropic birds common at Ponapé in
November and December, 1930, in forested regions and along the cliffs.
He made similar observations at Kusaie and Palau. At Ponapé and Palau,
Coultas noted the use of the eggs, young and adults as food by the
natives. At Palau the plumes are used in headdresses worn by the
natives, the birds being taken with the blowgun.
Murphy (1936:807) states that the principal enemy of the White-tailed
Tropic Bird at Bermuda is the introduced rat (_Rattus rattus_).
Introduced rats, particularly _Rattus mindanensis_ on Guam, may prey on
the nesting birds. Baker (1946c:404) writes that this rat is a good
climber and may spend considerable time in trees. The rat was trapped
also in rough coral jungle at the edge of the cliffs, where tropic
birds, Micronesian Starlings and other species, may have been nesting.
Little has been recorded concerning the post-breeding season wanderings
of these tropic birds in Micronesia. They seemingly spend considerable
time at sea, but whether they move as far from their breeding areas as
do birds in the Atlantic, as reported by Murphy (1936:803), Baker
(1947a:253) and others, is not known.
Murphy (1936:796) notes that the northward distribution of the tropic
birds in the Atlantic is dependent on the warm currents of water. In the
western Atlantic, the poleward-flowing, warm currents of the Gulf Stream
allow for the northern extension of the range of these birds to Bermuda.
In the eastern Atlantic, cool currents flowing toward the equator
restrict the northern range. The same condition prevails in the eastern
Pacific where warm current flowing toward the pole enable the birds to
range north to the Bonins and other islands.
The three species of tropic birds known from Micronesia overlap very
little in their ranges in this area. The White-tailed Tropic Bird has
become firmly established in the western part of Micronesia, but there
are only a few records from the extreme eastern part. The Red-tailed
Tropic Bird appears to be resident only in the northern Marianas
although it has been recorded in the Carolines and Marshalls.
Interspecific competition may prevent considerable intermingling of
breeding populations in Micronesia, or it may be that each species
requires different ecologic conditions.
=Sula dactylatra personata= Gould
Masked Booby
_Sula personata_ Gould, Proc. Zool. Soc. London, 1846, p. 21. (Type
locality, North and northeast coasts of Australia = Raine Island.)
_Sula cyanops_ Finsch, Ibis, 1880, p. 219 (Taluit); Wiglesworth,
Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p.
72 (Marshalls); Ogilvie-Grant, Cat. Birds British Mus., 26, 1898,
p. 430 (Marshalls).
_Parasula dactylatra personata_ Kuroda, in Momiyana, Birds
Micronesia, 1922, p. 35 (Marshall Islands); Mathews, Syst. Avium
Australasianarum, 1, 1927, p. 232 (Marshall Islands).
_Sula dactylatra personata_ Yamashina, Tori, 7, 1932, p. 407
(Medinilla); Hand-list Japanese Birds, rev., 1932, p. 187
(Medinilla, Marshall Islands); Hand-list Japanese Birds, 3d ed.,
1942, p. 208 (Medinilla, Marshall Islands).
_Geographic range._--Central and western Pacific from the Hawaiian
Islands south to Australia, probably also in the Indian Ocean. In
Micronesia: Mariana Islands--Medinilla; Marshall Islands--Jaluit?
_Characters._--Adult: A large, white sea bird, with brown wings
and tail; face dark blue; bill horn-colored with base
orange-yellow in males and pink or light red in females; feet
olive in males and lead gray in females.
Immature: Resembles adult, but head, wings, tail, chin and throat
dark brown; some white mottling may be present on back and rump;
bill dark; feet lead colored.
_Nesting._--Yamashina (1932a:407) reports the taking of 12 eggs on
February 19, 1931, at Medinilla Island in the Marianas.
_Remarks._--No specimen has been examined by me from the area reported
upon. Little is known regarding the distribution of the Masked Booby in
Micronesia. It is found on the island groups which surround Micronesia
and future field observations probably will add to our knowledge of its
occurrence in this area. It is known to be resident only in the northern
Marianas.
=Sula sula rubripes= Gould
Red-footed Booby
_Sula rubripes_ Gould, Syn. Birds Australia, pt. 4, 1838, app., p.
7. (Type locality, New South Wales = Raine Island.)
_Pelecanus piscator_ Kittlitz, Obser. Zool., in Lutké, Voy. "Le
Séniavine," 3, 1836, pp. 296, 299 (Lougounor = Lukunor); _idem_,
Denkw. Reise russ. Amer. Micron. und Kamchat., 1, 1858, p. 351
(Lugunor).
_Dysporus piscator_ Hartlaub, Proc. Zool. Soc. London, 1867
(1868), p. 831 (Pelew); Hartlaub and Finsch, Proc. Zool. Soc.
London, 1868, pp. 9, 118 (Pelews); _idem_, Proc. Zool. Soc.
London, 1872, p. 90 (Pelew); Finsch, Journ. Mus. Godeffroy, 8,
1875, pp. 6, 47 (Palau).
_Sula piscatrix_ Wiglesworth, Abhandl. und Ber. Zool. Mus.
Dresden, no. 6, 1890-1891 (1891), p. 72 (Pelew, Luganor);
Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 64
(Rota, Palaos, Carolines); Hartert, Novit. Zool., 5, 1898, p. 68
(Marianne); Safford, Osprey, 1902, p. 70 (Rota); _idem_, The Plant
World, 7, 1904, p. 267 (Guam); _idem_, Contr. U. S. Nat. Herb., 9,
1905, p. 80 (Guam); _idem_, Guam, 1912, p. 19 (Guam); Cox, Island
of Guam, 1917, p. 22 (Guam).
_Sula piscator_ Ogilvie-Grant, Cat. Birds British Mus., 26, 1898,
p. 432 (Pelew); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901,
p. 24 (Guam).
_Piscatrix sula rubripes_ Kuroda, in Momiyana, Birds Micronesia,
1922, p. 34 (Pelew, Luganor, Rota).
_Sula sula rubripes_ Hand-list Japanese Birds, rev., 1932, p. 185
(Medinilla, Saipan, Rota, Palau, Lukunor, Likieb); Bryan, Guam
Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Yamashina, Tori, 10,
1940, p. 676 (Maug, Bikar); Hand-list Japanese Birds, 3d ed.,
1942, p. 208 (Maug, Medinilla, Saipan, Rota, Palau, Lukunor,
Bikar, Likieb).
_Geographic range._--Indian Ocean east to central Pacific islands.
In Micronesia: Mariana Islands--Maug, Medinilla, Saipan, Rota;
Palau Islands--exact locality unknown; Caroline Islands--Lukunor;
Marshall Islands--Bikar, Likieb, Bikini, Eniwetok.
_Characters._--Adult: A large sea bird with plumage of variable
color, mainly white or partly buff with black primaries and
black-tipped secondaries, or grayish or brownish with white or
grayish tail; throat blackish; face blue or green; bill bluish and
lighter at tip; legs and feet red.
Immature: Resembles adult, but often wholly brownish, lighter
ventrally; bill blackish; feet yellowish red. Immature resembles
that of _S. leucogaster_.
_Nesting._--Morrison obtained a male nestling at Bikini on May 3,
1946.
_Specimens examined._--Total number, 10 (3 males, 7 females) from
Marshall Islands, USNM--Bikini (April 28, May 1, 2, 3).
_Remarks._--The writer saw several birds approximately 20 miles east of
Eniwetok on January 7, 1945. Morrison obtained a series of birds at
Bikini in April and May, 1946. Murphy (1936:861-870) presents a wealth
of information concerning the bird. He points out the need for a better
understanding of the plumages of the adult birds and gives evidence that
the birds of different colors may occur within the same population. He
describes the Red-footed Booby as nesting in trees and shrubs. This type
of nesting environment is present at many of the islands in Micronesia.
=Sula leucogaster plotus= (Forster)
Brown Booby
_Pelecanus Plotus_ Forster, Descr. Anim., ed. Licht., 1844, p. 278.
(Type locality Near New Caledonia.)
_Dysporus sula_ Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p.
831 (Pelew); Hartlaub and Finsch, Proc. Zool. Soc. London, 1868,
pp. 9, 118 (Pelew); _idem_, Proc. Zool. Soc. London, 1872, p. 90
(Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 6, 47
(Palau); _idem_, Proc. Zool. Soc. London, 1880, p. 577 (Ruk);
Hartert, Novit. Zool., 7, 1900, p. 11 (Ruk).
_Sula fusca_ Finsch, Ibis, 1880, p. 218 (Taluit).
_Sula leucogastra_ Salvadori, Ornith. Papuasia, 3, 1882, p. 423
(Pelew, Carolinis); Wiglesworth, Abhandl. und Ber. Zool. Mus.
Dresden, no. 6, 1890-1891 (1891), p. 72 (Pelew, Ruk, Marshalls);
Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 63
(Palaos, Mariannes, Marshalls, Carolines); Hartert, Nov
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