Pacific Islands

The Whitney South Sea Expedition

Ernst Mayr's primary task, when he arrived at the AMNH in January 1931, was to study the collections of birds sent in by the Whitney South Sea Expedition (WSSE) which, at that time, continued field work in the southern Pacific Ocean and eventually developed into the longest, geographically most extensive and scientifically one of the most important ornithological expedition ever undertaken. Travelers were continuously in the field from 1920 until 1940 and R. C. Murphy at the AMNH functioned as general manager, but he never joined them anywhere during this entire period. He once got as far as California on his way to join the WSSE, but was summoned back by Dr. Sanford. Although several status reports have been published while the expedition was underway (Murphy 1922, 1924, 1938; Chapman 1935), no general overview as to where and when birds were collected over the 20-year period ever appeared after finishing in Australia in the middle of World War II (but see the recent brief account by LeCroy 2005). The "Introductions" to the two bound volumes of individual papers on the "Birds collected during the WSSE" (No. 1-25 and No. 26-50) prepared and published by Mayr in 1933(n) and 1942(f), respectively, include brief comments on the expedition and provide very useful lists of the individual papers, of bird species and problems discussed. Mayr (1942e: 12) summarized the accomplishments of the expedition in a few sentences and stated that a considerable part of his book was based on the magnificent material at hand. Rich collections were also made of mammals, reptiles, insects, mollusks and other groups. In 1969, Edwin H. Bryan, Jr., entomologist and curator of the Bishop Museum, Hawaii, from 1919 to 1968 and a member of the expedition in 1924, prepared an unpublished chronological summary of and guide to the manuscript journals and records of the WSSE until 1935 (on file in the Department of Ornithology, AMNH). However, the last years (1936-1940), when Lindsay Macmillan collected partly with the aid of Whitney funds are not included in Bryan's report. Macmillan's collecting stopped when he went into military service during World War II.

Plans for the WSSE probably originated through the friendly rivalry between Thomas Barbour and Leonard Sanford, both of whom wanted to help their respective museums, the Museum of Comparative Zoology and the AMNH, to be the richest in the world in rare species of birds (p. 100). The islands in Polynesia and Micronesia were famous for such species and Sanford apparently got the idea to launch an expedition funded by the Harry Payne Whitney family that would visit all the islands in the Pacific apt to have endemic species.

The first leader was Rollo H. Beck (1870-1950) who started field work in the Society Islands in 1920 and, over a year later, purchased a seaworthy two-masted schooner, the "France," to be able to visit small islands independently. This vessel was operated until July 1932, when it was sold. Beck was the most successful collector of seabirds in the world. He had participated in expeditions to the Galapagos Islands for Lord Rothschild in 1897 and 1901 and had led the Brewster-Sanford Expedition to the coastal waters of South America (1912-1917). Soon afterwards he began to prepare for the WSSE. He resigned from this task in 1928. From 1930 until his death he grew apricots, figs, and almonds in California (Pitelka 1986; Mearns and Mearns 1998). Besides several other persons, his longtime assistants were E. H. Quayle and José G. Correia. After Beck had retired, Hannibal Hamlin was in charge (1928-January 1930) followed by William F. Coultas (January 1930-1935) and L. Macmillan (1936-1940).

The WSSE explored most island groups in the Pacific Ocean (Fig. 4.1), all together more than 3,000 islands. Owing to the rapid changes in the South Sea region through habitat destruction, this was the last chance to make representative collections on the South Sea Islands. The typed and bound journals and letters of expedition members total 31 volumes. Two additional ones by Charles Richmond (Washington) contain geographical notes on most island groups in the Pacific prepared at the request of Dr. Sanford since mid-1918 and used during the detailed planning of the various stages of the expedition. This material is kept in the Department of Ornithology (AMNH). During World War II some of these volumes describing work of the expedition in certain islands of the southwest Pacific Ocean became important source material for US governmental agencies.

Starting in the east, birds of the Society, Christmas, Tuamotu and Marquesas Islands were collected in 1920-23, followed by those of the Cook, Samoa, Phoenix, Fiji, and Tonga Islands in 1923-25. The expedition sampled the avifauna of the New Hebrides (Vanuatu) and Santa Cruz Islands in 1926-1927 prior to collecting on some of the Solomon Islands and the islands off the southeastern tip of New Guinea during the period 1927-30. It then continued to the Carolinas, Marianas and Palau Islands in late 1930 and 1931, and, after the "France" had been sold, worked on New Britain in 1932-33 as well as on the Admiralty Islands and on the small islands off New Ireland in 1934-35. Additional work was done by L. Macmillan in the New Hebrides (Vanuatu, 1936-37), on the Loyalty Islands and on New Caledonia (193839). The expedition ended in mid-1940 in Australia where Macmillan collected in several inland regions of Queensland (east of Windorah, southeast of Boulia, eastern edge of Simpson desert, Birdsville area, and Dalby region) to provide comparative material for the Mathews type collection in New York.2

The only island groups not visited by the WSSE were the Hawaii Islands in the north and New Zealand in the south (both already well sampled in previous years) and the Ellice (Tuvalu), Gilbert (Kiribati) and Marshall Islands in the central tropical Pacific. No endemics were known from these latter island groups and none would be expected from there. These are low lying coral atolls and certainly have been flooded completely during high Pleistocene sea-level stands. No new subspecies have been described from there in the 70 years since the WSSE bypassed these islands. Ignoring them was deliberate.

The Whitney Hall of Oceanic Birds at the AMNH was designed with 18 habitat groups representing a range of Pacific island types from low lying atolls to high volcanic islands. To obtain the necessary photographs and other information for these habitat groups, three additional expeditions were undertaken by museum staff as guests on private yachts to particular Pacific islands in 1934, 1936, and 1940.

The results of taxonomic studies were published in the series "Birds collected by the Whitney South Sea Expedition" (American Museum Novitates) between

2 The large private collection of G. Mathews was bought by W. Rothschild who had apparently promised Mathews that it would go to the British Museum of Natural History (London). Mathews was upset when his collection was sold to the AMNH along with the rest of the Rothschild Collection in 1932. One of the things Mayr had planned to do was to finish a list of Mathews' types, a task that Hartert had begun in Tring. However, Mayr was unable to complete this type list, but he left at the AMNH his card file of Mathews' taxonomic names which is still very useful today (M. LeCroy, pers. comm.).

1924 and 1957 by 14 authors and coauthors totaling 64 reports, 977 printed pages. More than half of this total (61.5%) was written by Ernst Mayr, curator of the Whitney and Rothschild Collections since 1932 and the first ornithologist able to devote full time to the study of these collections. 28 new species and 247 new subspecies have been described until 1953 (Murphy, unpubl. manuscript, 1953) plus nine subspecies described by Mayr (1955a, 1957b). Comparative material for Mayr's taxonomic studies of the Whitney birds was contained in the Mathews Collection of Australian birds at the AMNH and in the Rothschild Collection, particularly the rich material from New Guinea, the Bismarcks, and the Solomon Islands.

Significance of the Whitney South Sea Expedition

Islands and island faunas represent thousands of experiments by nature of assembling animal communities (Mayr 1967f). There are many groups of fairly similar islands in the tropical oceans which differ in area, isolation and elevation. Islands have contributed decisively to the understanding of evolution and population biology. Following research on the Canary Islands in 1815, Leopold von Buch was the first to propose the theory of geographic speciation. The Galapagos Archipelago opened Charles Darwin's eyes to evolution and natural selection. The Malay Archipelago gave Alfred R. Wallace his insights into biogeography. The islands of the southwest Pacific and New Guinea taught Ernst Mayr geographic variation and speciation of animals. In recent decades islands stimulated biologists of the next generation to study ecology, behavior and conservation biology (J. Diamond, R. MacArthur, S. Olson, E. Wilson).

The most complete exploration of the Pacific islands by the WSSE provided the database for all subsequent studies of birds inhabiting the world's most extensive set of islands. This is the unique importance of this expedition. In particular it provided the basis for Ernst Mayr's analysis of variation and speciation in birds (Mayr 1942e, Mayr and Diamond 2001g, Schodde 2005). Among the phenomena discussed are many cases of simple and more complex geographical variation, primary and secondary intergradation of populations. Numerous well differentiated peripheral island forms represent borderline cases between subspecies and species and between species and monotypic genera demonstrating the continuity of the process of geographic speciation over time. Mayr realized that geographic variation provides the two components of speciation-divergence and discontinuity. Sympatry of distinct taxa indicates their status as species. Moreover, out of the biology and systematics of Polynesian birds Mayr (1940i) developed the basic tenets of "island biogeography" (p. 163). His detailed revisions of all subspecies and species of birds in Oceania also provided the basis for later conservation work in this region, particularly island endemics (Schodde 2005).

Not a single mountain bird was known from the Solomon Islands when the Whitney Expedition arrived there in 1927. No less than 17 mountain species, 11 of them new to science, were discovered. Of the 71 new taxa from northern Melanesia since 1940, most have been described from specimens collected earlier, only 23 from newly discovered populations (Mayr and Diamond 2001g: 34).

Studies of the Whitney Collections

In January 1931, Ernst Mayr plunged into his work on the Whitney collections which had arrived in New York since 1921 but not studied in detail (including his own collections from the Solomon Islands). He had about ten papers published or in press by the end of that year.

"I work here really like a madman. The revisions of Pachycephala are in press; currently I study the Polynesian flycatchers. As soon as the revisions of the genera are finished, I shall prepare books on (1) Polynesia, (2) Solomon Islands and Bismarck Group and (3) New Guinea" (to W. Meise on 11 April 1932; transl.) and "I sit on two undescribed genera and many new species, among them an eagle. I would never have dreamed of something like that; I no longer describe 'dirty' subspecies unless for zoogeographical reasons" (to W. Meise, October 1931; transl.).

Mayr took notes on plumage colors and measured thousands of bird specimens (wing, tail, bill, tarsus) determining the individual variation of local populations and the geographical variation of subspecies and species. "He worked as a field naturalist but to laboratory standards of inference and proof-the essence of border practice" (Kohler 2002: 265). In some of his articles Mayr treated the avifauna of particularly interesting islands, in others he revised differentiated genera or species groups monographically. In the first paper (1931b) which appeared only two months after he had started to work at the AMNH, he introduced into the international literature the important concept of "superspecies" as an equivalent of the term "Artenkreis" coined by Rensch (1928,1929). Mayr had read Rensch's book, The Principle of Polytypic Species and the Problem ofSpeciation (1929) upon his return from the Solomon Islands in 1930 and admired it greatly. He defined superspecies as "a systematic unit containing geographically representative species that have developed characters too distinct to permit the birds to be regarded as subspecies of one species" (1931b) explaining:

"I regard superspecies as a convenient compromise between diverse schools of ornithologists, the extremely modern ones, on one side, who want to put together as a species all geographical representatives, disregarding the most striking morphological differences, and the conservatives, on the other side, who demand perfect intergradation as a criterion" (p. 2).

This paper (1931b) is devoted to a study of the widespread Collared Kingfisher (Halcyon chloris). Mayr described several new subspecies from the New Hebrides, Santa Cruz Islands, and Rennell Island noticing the conspicuous differentiation of peripheral isolates: "The birds of the outposts, especially at the periphery of distribution, show advanced characters that lead to pronounced differences in appearance" (p. 1). "The sympatric occurrence of two taxa on the same island proves that they cannot belong to one species" (p. 3).

His second article (1931d) dealt with the isolated Rennell Island, a raised atoll 90 miles southwest of the Solomon Islands. Here "the bird fauna [.] has turned out to be one of the most interesting in the whole South Sea," because of its extraordinary endemism: 20 of about 33 native species were endemic species or subspecies. He described no less than three new species (one of them later reduced to subspecies rank) and 14 new subspecies. As an oceanic island, Rennell has received all of its fauna by dispersal across water barriers, from the Santa Cruz Islands and the New Hebrides in the east (30% of the native birds; 56% of the prevailing winds come from the SE or E), from the Solomon Islands in the north (48% of the native birds; 16% of the winds come from NW, N or NE), and from New Guinea and Australia in the west and southwest (5% of the winds come from the W or SW). The very frequent winds from the east compensate somewhat the greater distance of the eastern source region. Studies of particularly variable species like, e.g., the Golden Whistler (Pachycephala pectoralis; 1932c,d) and the Scarlet Robin (Petroica multicolor; 1934b), led to discussions of the genetic or hormonal control of bird plumages (1933l).

In monographic studies of particular species and species groups Mayr analyzed geographical variation on a regional scale, as illustrated by, e.g., the thrushes of the Turdus javanicus-poliocephalus group (Fig. 4.4). From Solomon Islands and New Guinea to the west they are high-mountain birds, usually not found below 2,000 m elevation, but some of the populations in southern Melanesia and in Polynesia occur in the lowlands or even on small coral islands. Subspecies from neighboring islands are sometimes more distinct (e.g., in the Fiji Islands) than those from opposite ends of the range. Other examples Mayr discussed include species of fruit doves, trillers, and fantails.

When the southwestern Pacific Ocean became a Theater of Operations during World War II, the demand for a field handbook or field guide to the birds of the islands was great. Ernst Mayr, the expert of this region, produced such a book in a relatively short time. It appeared in 1945(n) under the title Birds of the Southwest Pacific. The book covered the birds of Samoa, Fiji, New Caledonia, New Hebrides (Vanuatu), Banks and Santa Cruz Islands, Solomon, Marshall, Caroline, Mariana and Palau Islands, 803 forms in total (388 species and 415 subspecies). The layout is a happy compromise between a strictly systematic and a geographical treatment. Wide-ranging species like sea birds and shore birds, are presented in the first chapters. The land and fresh-water birds are grouped systematically in one section and geographically by seven island groups in Part II of the book. This organization permitted a separate treatment of all the endemic species of seven different island groups and yet avoided space-consuming repetition of the more wide-spread species. Mayr summarized the then available knowledge of these island birds and emphasized the many gaps particularly regarding life history, again and again stating "habits unknown" to encourage the observer in the field to gather more information. Lists of questions relating to the behavior and ecology of birds are included in the introduction. The book comprises this whole avian fauna in a manner which satisfied both the amateur observer in the field and the specialist in the museum. It also contains much unpublished data from personal research.

Three color plates by Francis Lee Jaques and numerous excellent line drawings by Alexander Seidel illustrate 55 species of birds3. A second edition appeared in 1949. When the copyright had expired, two different reprints were published immediately; one in Hawaii and the other in England (Wheldon and Wesley Ltd., 1968); still another one came out in the States in 1978. Ernst Mayr was delighted that his book got such wide distribution. Since taxonomically nothing of importance has happened in the area, Birds of the Southwest Pacific is still reasonably up-to-date. Of course, there are today several more recent field guides available, like South Pacific Birds (duPont 1976), Birds of Hawaii and the Tropical Pacific (Pratt et al. 1987), Birds of the Solomons, Vanuatu and New Caledonia (Doughty et al. 1999) and A Guide to the Birds of Fiji and western Polynesia (Watling 2001) with excellent color illustrations of all species and many subspecies of the birds. Rollin Baker (1951) published a comprehensive account of the avifauna of Micronesia based on collections assembled during World War II and comparisons with Whitney material at the AMNH.

Mayr was the bird specialist for the whole wide region from the Solomon Islands to Polynesia. Being the authority for a vast area gave Mayr some satisfaction, but he always regretted that he did not have competitors (pers. comm.). In many areas of the world various specialists usually have a great time disagreeing with each other. Here in Oceania, what Mayr said was correct. Only in the Papuan Region did he encounter occasional dissent, e.g., when he overlooked two sibling species, Pachycephala melanura and Meliphaga orientalis.

Several young ornithologists soon started to work with the Whitney material independently but under Mayr's supervision. These were Dean Amadon who published three papers in the Whitney series entitled "Notes on some non-passerine genera" (1942a, 1942b, 1943), Dillon S. Ripley and Hugh Birckhead who studied "The fruit pigeons of the Ptilinopus purpuratus group" (1942). Amadon stayed at the AMNH, later becoming the Chairman of the Bird Department; Ripley became -►

Fig.4.4. Distribution and character variation of the Island Thrush (Turdus poliocephalus group). Map from Mayr (1942e: 58), illustrations of birds from MacKinnon and Phillipps (1993, Indonesia), Doughty et al. (1999, Solomons and Vanuatu) and Pratt et al. (1987; Fiji and Samoa)

3 Whereas F. L. Jaques (1887-1969) was a well-known bird artist employed by the AMNH, A. Seidel remains unknown in ornithological circles. He was born in Germany where he studied art first in Munich and then, for five years, in Rome. His early work included murals for an industrial concern in Rüdersdorf and settings and costumes for a theater in Berlin. He came to the United States as a tourist in 1939 and decided to stay, when the war broke out. For some time he was a houseguest with Ernst and Gretel Mayr and from 1943 to 1961 a staff artist for the AMNH where he illustrated many ornithological books and scientific papers and painted murals of extinct birds, saurians, and primates. He has provided illustrations for Collier's Encyclopedia and the Encyclopedia Americana and has published two books for young people, about wild birds and water mammals (biography prepared by Steuben Glass, AMNH, March 1963).

an ornithologist at the Peabody Museum at Yale University and later the secretary (director) of the Smithsonian Institution; H. Birckhead was killed in action during World War II (Mayr 1945b); training of several volunteers in the Bird Department is mentioned above (p. 120).

New Guinea

During the 1930s and 1940s Ernst Mayr was also very much engaged to his first "love affair," the birds of New Guinea, with the aim of publishing a taxonomic overview of the entire avifauna of this large island. The last comprehensive account on New Guinea birds, T. Salvadori's Ornitología della Papuasia (1880-1882), as well as some reports on British and Dutch expeditions, were hopelessly out of date, the compilation of G. Mathews (1927,1930) superficial and useless. The only modern paper on New Guinea birds using trinominals was Stresemann's (1923) on the birds of the German Sepik expedition.

The acquisition by the AMNH of the Rothschild Collection (in 1932), with its extensive series of New Guinea birds, much facilitated Mayr's work from 1935 onward (p. 116). In addition, he visited the museums in London, Paris, Leiden, Hamburg, Berlin, Munich, Dresden, Frankfurt, Stuttgart and Basel in 1930,1932, 1934, and 1938 to examine doubtful type specimens. The types of the museum in Genoa were sent to Dresden. All this enabled him to complete the catalogue giving full synonymy lists and accurate descriptions of the range of each species and subspecies. About thirty specialized papers document the results of his taxonomic studies. He reviewed the subspecies of the Victoria Crowned Pigeon Goura victoria (with Berlioz, 1933m). From the collections of the 1933-34 expedition to southeastern New Guinea (Mafulu, Mt. Edward in the central range) financed, organized and guided by Mr. Richard Archbold of New York, Mayr and Rand (1935g, 1936c, 1936f) described 26 new subspecies and one new species (Eurostopodus archboldi). A massive report on the entire collection comprises 248 pages with detailed discussions of each species (Mayr and Rand 1937c). The birds of the 1936-37 and 1938-39 Archbold Expeditions were studied by A. L. Rand. Mayr continued to review the genera of New Guinea birds one by one, described several new subspecies (1936d) and determined the taxonomic position of certain isolated species such as the monotypic genera Paramythia (P. montium) and Oreocharis (O. arfaki) which he recognized as closely related to each other and as members of the flowerpeck-ers Dicaeidae (Mayr 1933g). Following Stresemann's example, he revised carefully some of the most difficult genera, such as Sericornis (1937a) and Collocalia (1937f). These were the most complicated groups of birds he ever tackled taxonomically with many exceedingly similar sibling species. Whenever he was interrupted in his work, he had to scrutinize them anew for several days to see the minute differences. With respect to Collocalia he wrote to Stresemann:

"On some days, and this is literally true, I sat there for 3-4 hours comparing a single specimen of hirundinacea with a single specimen of vanikorensis, or a single one of 'mearnsi' with one of germani. Eventually I had developed such a clear 'mental picture' of them that the classification of the other forms became much easier [...] These difficult beasts must be looked at from the front, the back, from above and below for hours" (9 March 1937; transl.).

The article on the swiftlets gave him a chance to explain the changes in taxo-nomic concepts within several decades: "The literature on this genus [Collocalia] illustrates exceedingly well the trends of ornithological classification. We see in the earlier part of this century conscientious efforts to analyze the characters of the various geographical races without much of an effort to combine the many disconnected units into natural groups of related forms. Oberholser's papers were written in this analytical stage. In opposition to this trend the Formenkreislehre gained increasing influence during the twenty's, emphasizing the principle of geographical representation frequently with disregard of a thorough morphological examination of the treated forms. During this period (1925-1926) Stresemann proposed a classification of this genus, which grouped all the then known forms in six species [...]. A reaction to this ultra-synthetic trend was inevitable, and Stresemann himself was the first to suggest the breaking up of these large Formenkreise into smaller, but more natural species" (1937f: 2).

Most of the non-passerine birds of New Guinea extend their ranges considerably beyond this region. Revisions of these species had to take into consideration the material of the Rothschild Collection and the collections of the Whitney South Sea Expedition made in the Bismarck Archipelago, the Louisiade and d'Entrecasteaux Archipelagoes as well as the Solomon Islands and Polynesia. Therefore Mayr included the papers on non-passerine families entitled "Notes on New Guinea Birds I-VIII" in the series "Birds collected during the WSSE" (No. 33, 35,36, 39-41,43, 45; 1937-1941). In 1939(c,f,g), Mayr and Meyer de Schauensee reported in several installments on the collections made by S. D. Ripley during the Denison-Crockett Expedition to western New Guinea (Biak Island, Vogelkop and western Papuan Islands) in 1936-38. Here Mayr interpreted the speciation process for the first time. The bird fauna of Biak Island demonstrates all stages of increasing differentiation. Among 69 species 20 have not changed when compared to the New Guinea mainland population, either because they are exceptionally stable, or because they have reached Biak only recently, or because they belong to common mainland species which continue to swamp the Biak population. Some of the remaining 49 species are slightly different; others have developed into moderately or even conspicuously different subspecies. Partly, they might with equal justification be considered species or subspecies, and still others are so different (5 species or 8, if Numfor Island is included) that no taxonomist will hesitate to call them species (Mayr and Meyer de Schauensee 1939: 9).

By the end of 1940, Mayr had completed a taxonomic revision of every genus in preparation of his List of New Guinea Birds. A systematic and faunal list of the birds of New Guinea and adjacent islands to be published by the AMNH in 1941(f). Only the specialist is able to appreciate the quality of this work of which its author was justly proud. The List provided a sound basis on which later authors could build. Based on the Biological Species Concept, it gives an overview of the number, the systematic relations and the distribution of all the bird taxa of New

Guinea and surrounding islands (568 breeding bird species in 1,400 forms of the land and freshwater). Subspecies differentiation is conspicuous. For each form the name is followed by reference to the original description, a complete list of synonyms, and its range, and for each species there is a statement of habitat and altitudinal distribution. Species limits employed are broad to express relationships rather than differences among species and subspecies. Footnotes indicate which species together form a superspecies. A gazetteer of reference maps and collecting

Fig. 4.5. Distribution of the crow-sized Greater Birds of Paradise, Paradisaea apoda super-species of New Guinea (data from Gilliard 1969 and Cooper and Forshaw 1977). 1 P. rubra, 2 P. minor, 3 P. apoda, 4 P.raggiana, 5 P. decora. Adult males (illustrated) are maroon brown, breast mostly blackish, crown and nape yellow with two elongated central tail wires (or ribbons) and enormous flank plumes which are yellow (stippled) and white, orange or red (shaded); females are very different, smaller and lack flank tufts and tail wires. Ernst Mayr (1940c, 1942e) discussed geographical gradients in the color of back and flank plumes in P. raggiana of eastern New Guinea which are probably due to southeastward introgression of P. minor genes from the northcoastal lowlands. Hybridization (H) occurs in areas where the mainland species meet. Note strongly differentiated species on small islands off the coast of New Guinea near its northwestern and southeastern tips

Fig. 4.5. Distribution of the crow-sized Greater Birds of Paradise, Paradisaea apoda super-species of New Guinea (data from Gilliard 1969 and Cooper and Forshaw 1977). 1 P. rubra, 2 P. minor, 3 P. apoda, 4 P.raggiana, 5 P. decora. Adult males (illustrated) are maroon brown, breast mostly blackish, crown and nape yellow with two elongated central tail wires (or ribbons) and enormous flank plumes which are yellow (stippled) and white, orange or red (shaded); females are very different, smaller and lack flank tufts and tail wires. Ernst Mayr (1940c, 1942e) discussed geographical gradients in the color of back and flank plumes in P. raggiana of eastern New Guinea which are probably due to southeastward introgression of P. minor genes from the northcoastal lowlands. Hybridization (H) occurs in areas where the mainland species meet. Note strongly differentiated species on small islands off the coast of New Guinea near its northwestern and southeastern tips localities in New Guinea at the end of the book is most useful to the user. The classification of the families used in this book follows Wetmore's proposal as far as the non-passerine groups are concerned and Stresemann's proposal for the Passeriformes.

Fig. 4.6. Distribution of jay-sized Paradise Magpies, Astrapia nigra superspecies, of New Guinea (data from Gilliard 1969, and Cooper and Forshaw 1977). 1 A. nigra, 2 A. splen-didissima, 3 A. mayeri, 4 A. stephaniae, 5 A. rothschildi. Adult males (illustrated) are mainly black with much green and purple iridescence, tail greatly elongated and black or black and white to white; females are more brownish with barred underparts. Hybridization has been recorded in the zone of contact between A. mayeri and A. stephaniae. Ernst Mayr (1942e, 1945h) used this group to discuss allopatric speciation: These five species, "descending from a common stock, have differentiated under conditions of geographical isolation. Each is restricted to a single mountain range, and none can exist in the lowlands. The differences acquired by these five species are a graphic illustration of evolution."

Fig. 4.6. Distribution of jay-sized Paradise Magpies, Astrapia nigra superspecies, of New Guinea (data from Gilliard 1969, and Cooper and Forshaw 1977). 1 A. nigra, 2 A. splen-didissima, 3 A. mayeri, 4 A. stephaniae, 5 A. rothschildi. Adult males (illustrated) are mainly black with much green and purple iridescence, tail greatly elongated and black or black and white to white; females are more brownish with barred underparts. Hybridization has been recorded in the zone of contact between A. mayeri and A. stephaniae. Ernst Mayr (1942e, 1945h) used this group to discuss allopatric speciation: These five species, "descending from a common stock, have differentiated under conditions of geographical isolation. Each is restricted to a single mountain range, and none can exist in the lowlands. The differences acquired by these five species are a graphic illustration of evolution."

Examples of two superspecies of birds of paradise, Mayr's favorite birds4, are illustrated in Figs. 4.5 and 4.6. Character gradients across hybrid zones occur in the Greater Birds of Paradise, geographical isolation and conspicuous differentiation is demonstrated in the Paradise Magpies. In a study of the Ribbon-tailed Bird of Paradise (Astrapia mayeri) Mayr and Gilliard (1952a) discussed the As-trapia superspecies. A. mayeri differs conspicuously from its representatives to the west (A. splendidissima) and to the east (A. stephaniae) but some gene flow exists between stephaniae and mayeri in the area where they have come into contact during recent geological time. These latter taxa are very close biologically. Partial overlap of closely related species occurs in the paradise kingfishers of the genus Tanysiptera (Fig. 4.7). During the Pleistocene T. hydrocharis was isolated on an island stretching from the Aru Islands to the mouth of the Fly River and thus separated from the mainland form galatea by a branch of the ocean. When this

Fig. 4.7. Species and subspecies of the Paradise Kingfishers, Tanysiptera hydrocharis-galatea group. The subspecies 1,2, and 3 of galatea on the mainland of New Guinea are exceedingly similar to each other. The subspecies vulcani (4) and rosseliana (5, on Rossel Island east of New Guinea, not shown) are much more distinct. The populations on Biak (6), Numfor (7), and Koffiao (8) have reached species level. The form on Aru Island, hydrocharis (H1), has also reached species rank and now coexists in southern New Guinea (H2) with a subspecies of galatea (3); slightly modified from Mayr (1942e, Fig. 15)

Fig. 4.7. Species and subspecies of the Paradise Kingfishers, Tanysiptera hydrocharis-galatea group. The subspecies 1,2, and 3 of galatea on the mainland of New Guinea are exceedingly similar to each other. The subspecies vulcani (4) and rosseliana (5, on Rossel Island east of New Guinea, not shown) are much more distinct. The populations on Biak (6), Numfor (7), and Koffiao (8) have reached species level. The form on Aru Island, hydrocharis (H1), has also reached species rank and now coexists in southern New Guinea (H2) with a subspecies of galatea (3); slightly modified from Mayr (1942e, Fig. 15)

4 In the foreword to Gilliard's book on the birds of paradise and bower birds, Mayr wrote: "Every ornithologist and birdwatcher has his favorite group of birds, whether they be nightingales or storks, hummingbirds or penguins. Frankly, my own are the birds of paradise and bower birds, [...] for in their ornamentation and courtship behavior birds of paradise are not surpassed in the whole class of Aves" (1969f).

strait fell dry the island joined with the mainland of New Guinea, and galatea invaded the range of hydrocharis, where the two species now live side by side without interbreeding and without obvious ecological competition. T. galatea displays no significant geographical variation in the vast area of New Guinea despite strong ecological contrasts. Yet each of the adjacent islands inhabited by this kingfisher has a markedly differentiated race or species even though they are in the same climatic zone as the neighboring mainland. Due to this observation and numerous similar examples in the literature Mayr (1954c) later proposed the theory of a relatively rapid genetic reorganization in small speciating populations (p. 219). Several sidelines to Mayr's taxonomic research on the birds of Oceania developed into additional publications on the avifaunas of Australia, the Malay Archipelago and Burma (Myanmar).

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