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SUMMARY The electrophcrctic profiles of the egg-white proteins of 359 species of non-passerines and at least 300 species of passerines have been studied. This paper is concerned primarily with the non-passerines. Protein structure is genetically determined and tends to be phylogenetically more conservative than most other characters used in taxonomy. The electrophoretic profiles provide an index to some aspects of protein structure and hence to phylogenetic relationships. The present technique is described and his been found to be most informative at the generic, familial and ordinal levels. Individual variation, variation among morphological “breeds” of Domestic Fowl, and variation within species, genera, families and orders have been taken into account in the comparisons. The principal conclusions are as follows: 1. The Struthioniformes and Casuariiformes arc probably related but the relationships of these to the Rheiformes are uncertain. 2. The Tinamiformes do not seem to be related to the Rheiformes or to the Galliformes. 3. The Pelecaniformes may be polyphyletic but this is uncertain. 4. The three available species of Sula have remarkably different egg-white profiles. The significance of these differences is not known. 5. Anhinga and Phalacrocorax are closely related and may be included in the same subfamily. 6. The Flamingos are related to the Ciconiiformes, not to the Anseriformes. 7. The Gaviiformes seem to be more closely related to the Charadriiformes than to any other group. 8. The Aramiclae are closer to the Rallidae than to the Gruidae. 9. The Gruiformes are probably polyphyletic. There is no evidence that Eurypyga or Psophia are closely related to the Gruidae, the Rallidae or each other. 10. The Gallrormes (Opisthocomus not studied) are a very close-knit monophyletic group. The order is divided into three families, Megapodiidac, Phasianidae, Opisthocomidae. As subfamilies of tht Phasianidae: Phasianinae, Meleagridinae, Numidinae, Tetraoninae, Cracinae. 11. The Anat dae are also monophyletic and closely related. Anseranas seems sufficiently distinctive to be placed in a monotypic tribe or possibly given subfamily status. 12. The Falconiformes- may be polyphyletic, the Falconidae possibly being unrelated to the other diurnal birds of prey. The Cathartidae are related to the Accipitridae. 13. The Strigiformes and Caprimulgiformes are related. 14. Turacos (Musophagidae) are cuculiform, apparently related to the Cuculidae through Centropus. 15. Merops, Momotus and the Alcedinidae are related to one another but seem unrelated to Eurystomus (Coraciidae). The Coraciiformes are therefore probably polyphyletic. 16. The genus Columba is probably polyphyletic, the Old World species being distinct from the New World species. 17. The Coliilormes and Trogoniformes are each distinctive and have no close relatives. Both may be related to the Passeriformes. 18. The swifts and hummingbirds are related to one another and possibly to the Passeriformes. 19. A request for help in obtaining additional material is made and instructions for collection and shipment art given.

Summary The egg white proteins of the large ratites (Struthio, Casuarius, Dromaius, Rhea), the kiwis (Apteryx) and several tinamous (Tinamidae) were compared with one another and representatives of several other groups of birds using the technique of isoelectric focusing in acrylamide gel. The tryptic peptides of the ovalbumins of the same groups were compared by thin-layer electrophoresis. The results indicate that the large ratites are more closely related to one another than any one of them is to any other living bird; that the kiwis are not closely related to any of the other groups with which they were compared; and that the tinamous are not closely related to any of the large ratites but may be distantly related to the Galliformes.

The traditional view of avian evolution places ratites and tinamous at the base of the phylogenetic tree of modern birds (Neornithes). In contrast, most recent molecular studies suggest that neognathous perching birds (Passeriformes) compose the oldest lineage of modern birds. Here, we report significant molecular support for the traditional view of neognath monophyly based on sequence analyses of nuclear and mitochondrial DNA (4.4 kb) from every modern avian order. Phylogenetic analyses further show that the ducks and gallinaceous birds are each other's closest relatives and together form the basal lineage of neognathous birds. To investigate why other molecular studies sampling fewer orders have reached different conclusions regarding neognath monophyly, we performed jackknife analyses on our mitochondrial data. Those analyses indicated taxon-sampling effects when basal galloanserine birds were included in combination with sparse taxon sampling. Our phylogenetic results suggest that the earliest neornithines were heavy-bodied, ground-dwelling, nonmarine birds. This inference, coupled with a fossil bias toward marine environments, provides a possible explanation for the large gap in the early fossil record of birds.

The origin of the flightless ratite birds of the southern continents has been debated for over a century. Whether dispersal or vicariance (continental breakup) best explains their origin depends largely on their phylogenetic relationships. No consensus has been reached on this issue despite many morphological and molecular studies. To address this question further we sequenced a 2.8-kb region of mitochondrial DNA containing the ribosomal genes in representative ratites and a tinamou. Phylogenetic analyses indicate that Struthio (Africa) is basal and Rhea (South America) clusters with living Australasian ratites. This phylogeny agrees with transferrin and DNA hybridization studies but not with sequence analyses of some protein-coding genes. These results also require reevaluation of the phylogenetic position of the extinct moas of New Zealand. We propose a new hypothesis for the origin of ratites that combines elements of dispersal and vicariance.

In most classifications of the past century, the rails (Rallidae) have been placed in the Gruiformes with the cranes and their allies, including the Sunbittern, bustards, Limpkin, sungrebes, trumpeters, seriemas, and the Kagu. In a few classifications the rails have been assigned to an Order Ralliformes; in other classifications some taxa now usually placed in the Charadriiformes have been assigned to the Gruiformes, as relatives of the Rallidae. DNA-DNA hybridization data support other evidence that the rails are closer to the typical gruiforms than to any other group, but that they have no close relatives within the Gruiformes.

The traditional avian Order Pelecaniformes is composed of birds with all four toes connected by a web. This "totipalmate" condition is found in ca. 66 living species: 8 pelicans (Pelecanus), 9 boobies and gannets (Sula, Papasula, Morus), ca. 37 cormorants (Phalacrocorax), 4 anhingas or darters (Anhinga), 5 frigatebirds (Fregata), and 3 tropicbirds (Phaethon). Several additional characters are shared by these genera, and their monophyly has been assumed since the beginning of modern zoological nomenclature. Most ornithologists classify these genera as an order, although tropicbirds have been viewed as related to terns, and frigatebirds as relatives of the petrels and albatrosses. DNA.DNA hybridization data indicated that the pelicans are most closely related to the Shoebill (Balaeniceps rex), a stork-like bird that lives in the swamps of central Africa; the boobies, gannets, cormorants, and anhingas form a closely related cluster; the tropicbirds are not closely related to the other taxa; and the frigatebirds are closest to the penguins, loons, petrels, shearwaters, and albatrosses (Procellarioidea). Most of these results are corroborated by DNA sequences of the 12S and 16S rRNA mitochondrial genes, and they provide another example of incongruence between classifications derived from morphological versus genetic traits.

To address the suitability of mitochondrial DNA sequence data for higher avian systematics, cytochrome b sequences for nine species of Cuculiformes and Galliformes were gathered and compared to those of the Hoatzin, a specialized bird whose phylogenetic affinities have long puzzled ornithologists. Additional avian cytochrome b sequences from GenBank also were incorporated into the comparisons. Various phenetic and parsimony analyses applied to the molecular data coded in four formats (nucleotide sequences, purines versus pyrimidines, first and second positions of codons, and translated amino acid sequences) yielded several consistent phylogenetic arrangements, including the distinction of Galliformes from Cuculiformes, a clade composed of the Guira Cuckoo and Groove-billed Ani (Crotophagidae) to the exclusion of the other assayed cuculiforms (Cuculidae and Coccyzidae), and a clade composed of the New World quail (Odontophoridae, in the Sibley-Ahlquist classification) as a sister group to most or all Old World galliforms assayed (Phasianidae and Numididae). The latter result is of particular interest because it supports a controversial systematic realignment of the Galliformes based on DNA-DNA hybridization data. With regard to the phylogenetic position of the Hoatzin, the analysis differed in face-value outcome, although alternative clades were in all cases poorly supported by bootstrapping, and internodal distances were small relative to the range of genetic separations within either Cuculiformes or Galliformes. These uncertainties in phylogenetic resolution of the Hoatzin appear to be attributable to shallow slopes in the regressions relating cytochrome b sequence differences to evolutionary time, in conjunction with homoplasy in the data, sampling error in the estimation of genetic differences, and the relatively close temporal placements of relevant evolutionary nodes.

Nucleotide sequences from the mitochondrial cytochrome b gene were used to address a controversial suggestion that New World vultures are related more closely to storks than to Old World vultures. Phylogenetic analyses of 1-kb sequences from 18 relevant avian species indicate that the similarities in morphology and behavior between New World and Old World vultures probably manifest convergent adaptations associated with carrion-feeding, rather than propinquity of descent. Direct sequence evidence for a close phylogenetic alliance between at least some New World vultures and storks lends support to conclusions reached previously from DNA.DNA hybridization methods and detailed morphology-based appraisals, and it illustrates how mistaken assumptions of homology for organismal adaptations can compromise biological classifications. However, there was a lack of significant resolution for most other branches in the cytochrome b phylogenetic reconstructions. This irresolution is most likely attributable to a close temporal clustering of nodes, rather than to ceiling effects (mutational saturation) producing an inappropriate window of resolution for the cytochrome b sequences.

Part 1: a brief history structure and properties of DNA gene structure and function genetic regulation DNA reassociation and thermal stability the sequence organization of the genome the families of repeated DNA homology comparative DNA-DNA studies materials and methods data analysis tempo of evolution demographic factors and rates of DNA evolution a chronological survey of the classification of birds principles and methods of classification classification of birds based on DNA-DNA hybridization melting curves and dendrograms. Part 2: accounts of the groups of birds.

Sibley and Ahlquist (1984, 1987) presented the results of a study of 514 DNA-DNA hybrids among the hominoids and Old World monkeys (Cercopithecidae). They concluded that the branching order of the living hominoid lineages, from oldest to most recent, was gibbons, orangutan, gorilla, chimpanzees, and human. Thus, a chimpanzee-human clade was indicated, rather than the chimpanzee-gorilla clade usually suggested from morphological evidence. The positions of the gibbon and orangutan branches in the phylogeny are supported by substantial evidence, but whether the chimpanzee lineage branched most recently from the human lineage or from the gorilla lineage remains controversial. The conclusions of Sibley and Ahlquist (1984, 1987) have been supported by several independent studies cited by Sibley and Ahlquist (1987), plus the DNA sequence data of Hayasaka et al. (1988), Miyamoto et al. (1988), Goodman et al. (1989, 1990), and the DNA-DNA hybridization data of Caccone and Powell (1989). The laboratory and data analysis methods have been criticized by Marks et al. (1988) and Sarich et al. (1989). In response to these critics, and for our own interests, we present a reanalysis of the Sibley and Ahlquist data, including a description of the corrections applied to the "raw counts." The validity of the laboratory methods is supported by the congruence of tree topology and delta values with those of Caccone and Powell (1989), although their tetraethylammonium chloride technique differs from the hydroxyapatite method in several respects. The utility of the T50H distance measure is indicated by its congruence with percent sequence divergence at least to delta T50H 30, as noted by Goodman et al. (1990). The Sibley and Ahlquist uncorrected data indicate that Pan is genetically closer to Homo than to Gorilla, but that Gorilla may be genetically closer to Pan than to Homo. Melting curves are presented for the pertinent experiments, plus one that includes representatives of most of the groups of living primates.

Since 1958, Apalopteron familiare has been placed in the Meliphagidae and called the Bonin Islands Honeyeater or Ogasawara Honeyeater. Previously it had been treated as a bulbul, a babbler, a sylviid warbler and a white-eye. Here we present 12S rRNA sequence evidence that shows that Apalopteron is a member of the white-eye family Zosteropidae, closely-related to the Golden White-eye (Cleptornis marchei) of the southern Mariana Islands, which was also misidentified as a honeyeater until its true affinities were revealed by field observations and DNA-DNA hybridization. The ecology and behavior of Apalopteron and Zosterops are compared and reviewed. The English name Bonin Islands White-eye is proposed for Apalopteron familiare.

The first comparisons between molecules were made a century ago by the early serologists, but the molecular age of evolutionary biology truly began with the determination of the structure of DNA by Watson and Crick (1953). As the coding relationships among DNA, RNA and proteins became clear it was apparent that these molecules contain potential evolutionary information and methods to exploit them were soon in use. At Cornell University in 1956 I began to use electrophoresis to compare blood and egg-white proteins (e.g., Sibley 1960, 1970). These studies solved few problems, but they provided experience and contacts with persons who were developing improved procedures. I tried the "agar column" method of DNA-DNA hybridization in 1963, without success. It was the hydroxyapatite technique, perfected in the late 1960's, that made DNA hybridization useful for phylogenetic research and I began to use this method at Yale University in 1974, with the collaboration of Jon Ahlquist. Between early-1975 and mid-1986, we made more than 26,000 DNA-DNA comparisons among ca. 1700 bird species, representing all of the orders and 168 of the 171 families in Wetmore's (1960) classification. A new classification was proposed (Sibley et al. 1988). Sibley and Ahlquist (1990) provide details of the history, methods and data. A book on the distribution and taxonomy of the bird species of the world (Sibley and Monroe 1990) used the DNA-based classification and a supplement was published in 1993. A brief update (Sibley 1991) included comments and corrections for several group names. Monroe and Sibley (1993) is a list of living species with brief distributional information and corrections to date.

SIBLEY, C. G. and J. E. AHLQUIST. 1982. The relationships of the Australo-Papuan sittellas Daphoenositta as indicated by DNA-DNA hybridization. Emu 82: 173–176.The taxonomic relationships of Daphoe...

Summary Sibley, C. G. & Ahlquist, J. E. 1974. The relationships of the African sugarbirds (Promerops). Ostrich 45: 22–30. Certain characters of the sugarbirds (Promerops) seem to suggest that the genus may be a geographically isolated derivative of the Australo-Papuan Meliphagidae or a separate group of unknown ancestry, the Promeropidae. Both theories have received support to the present day. New data from comparisons of the egg whi te and red blood cell proteins, using the technique of isoelectric focusing in acrylamide gel, indicate that Promerops is a specialized starling and that an appropriate taxonomic treatment is to include the subfamily Promeropinae in the Sturnidae. This discovery not only explains the characters of Promerops but solves one of the most contentious zoogeographic problems in ornithology.

SIBLEY, C.G. and J.E. AHLQUIST. 1985. The phylogeny and classification of the Australo-Papuan passerine birds. Emu 85: 1–14.In a series of studies the technique of DNA-DNA hybridization has been us...

The taxonomic relationships of Drymodes were examined by comparing the single-copy DNA sequences of radio-iodine-labelled D. brunneopygia DNA with the DNAs of thirty-seven other genera of oscine passerines (Passeres). Of the taxa examined, the scrub-robins were found to be most closely related to Eopsaltria and Poecilodryas, and to be distant from the true thrushes (e.g. Turdus, Erithacus). Drymodes is a member of a varied assemblage of mostly endemic Australasian taxa that includes the Australian robins, flycatchers, monarchs, fantails, whistlers, shrike-thrushes, pitohuis, shrike-tits, the Crested Bellbird, and the quail-thrushes. The wedgebas, woodswallows, and other groups also may be part of this cluster. The honeyeaters, malurine wrens, and Australian magpies, apparently belong to other groups not yet defined in terms of DNA comparisons. The accentors (Prunella), sylviine warblers (Sylvia), white-eyes (Zosterops), muscicapine flycatchers, wagtails (Motacilla), mimic thrushes (Dumetella), starlings, typical wrens (Troglodytes), emberizine sparrows (Zonotrichia) and dippers (Cinclus) are as distant from Drymodes as are any taxa of oscines the DNAs of which have been compared.

The single-copy DNA sequences of the Bank Swallow (R. riparia) and the Barn Swallow (Hirundo rustica) were radio-labeled and compared with the DNAs of an array of other oscine species, using the technique of DNA-DNA hybridization. The results indicate that the swallows shared a most recent common ancestor with the sylviine-timaliine cluster, and that the divergence probably occurred ca. 50 mya, in the Eocene. The white-eyes (Zosterops) are also related to the swallow-warbler-babbler complex, as are the titmice, kinglets, bulbuls, nuthatches, creepers, wrens, verdins, and gnatcatchers. The fringillid-ploceid assemblage is the sister group of the swallow-warbler-babbler assemblage, with the muscicapine-turdine, and the corvine assemblages being progressively more distant.

(1987). The Relationships of Four Species of New Zealand Passerine Birds. Emu - Austral Ornithology: Vol. 87, No. 1, pp. 63-66.

Old World starlings have been thought to be related to crows and their allies, to weaverbirds, or to New World troupials. New World mockingbirds and thrashers have usually been placed near the thrushes and/or wrens. DNA-DNA hybridization data indicated that starlings and mockingbirds are more closely related to each other than either is to any other living taxon. Some avian systematists doubted this conclusion. Therefore, a more extensive DNA hybridization study was conducted, and a successful search was made for other evidence of the relationship between starlings and mockingbirds. The results support our original conclusion that the two groups diverged from a common ancestor in the late Oligocene or early Miocene, about 23-28 million years ago, and that their relationship may be expressed in our passerine classification, based on DNA comparisons, by placing them as sister tribes in the Family Sturnidae, Superfamily Turdoidea, Parvorder Muscicapae, Suborder Passeres. Their next nearest relatives are the members of the Turdidae, including the typical thrushes, erithacine chats, and muscicapine flycatchers.

Sibley, C. G. 1973. The relationships of the lyrebirds. Emu 74: 65–79.From the time of the discovery of Menura superba in 1798 until about 1853 the lyrebirds were usually thought to be allied eithe...

DNA-DNA hybridization was used to measure the average genomic divergence among the four chromosomal species of the Eurasian mole rats belonging to the Spalax ehrenbergi complex (Rodentia: Spalacidae). The percent nucleotide substitutions in the single-copy nuclear DNA among the species ranged from 0 to 5%, suggesting that speciation has occurred with minor genomic changes in these animals. The youngest chromosomal species appear to differ by 0.2-0.6% base pair mismatch, which is only between one and three base differences in a 500-bp fragment. The interspecific values of percent nucleotide differences permit the recognition of two well-separated speciation events in the S. ehrenbergi complex, the older (of Lower Pleistocene age) having isolated the chromosomal species 2n = 54 before the divergence of the three other species. DNA-DNA hybridization was also used to compare the Spalacinae (Eurasian mole rats), Murinae (Old World rats and mice), and Arvicolinae (voles and lemmings). These data enabled us to estimate the time of divergence of the spalacids at ca. 19 million years ago. The dates of divergence among the other rodent lineages, as predicted by DNA hybridization results, agree well with paleontological data. These dates of divergence are obtained by the relation between geological time and single-copy nuclear DNA change, a relation that was calibrated by Catzeflis et al. (1987) through the use of fossil Arvicolinae and Murinae data.

We present a classification of the living birds of the world based on the results of DNA-DNA hybridization studies. Several family-group names are presented formally for the first time; some of these names have appeared earlier in various publications.

The taxonomic relationships of the Australasian whistlers, or thickheads, were examined by comparing the radioiodine-labelled single-copy DNA sequences of the Golden Whistler Pachycephala pectoralis with the DNAs of fifty-five other species, representing fifty genera of oscine passerine birds (Passeres). Of the taxa examined, Pachycephala was found to be most closely related to other species of Pachycephala, to Pitohui, Colluricincla, Oreoica, Falcunculus, Rhagologus, and Daphoenositta, in that order.

The systematic relationships of the genus Malurus were examined by comparing the radioiodine-labelled ('iSI) single copy DNA sequences of the Variegated Fairy-wren Malurus lamberti with the DNAs of thirty-seven other species of oscine birds. Malurus lamberti was found to be most closely related to other species of Malurus, and to Stipiturus, Amytornis, the acanthizine thornbills and scrubwrens, and the honeyeaters, in that order. Malurus is not closely related to the sylviine warblers, the timaliine babblers, or the muscicapine flycatchers.

Twenty-two species of Hawaiian honeycreepers (Fringillidae: Carduelinae: Drepaninini) are known. Their relationships to other groups of passerines were examined by comparing the single-copy DNA sequences of the Apapane (Himatione sanguinea) with those of 5 species of cardueline finches, 1 species of Fringilla, 15 species of New World nine-primaried oscines (Cardinalini, Emberizini, Thraupini, Parulini, Icterini), and members of 6 other families of oscines (Turdidae, Monarchidae, Dicaeidae, Sylviidae, Vireonidae, Corvidae). The DNA-DNA hybridization data support other evidence indicating that the Hawaiian honeycreepers shared a more recent common ancestor with the cardueline finches than with any of the other groups studied and indicate that this divergence occurred in the mid-Miocene, 15-20 million yr ago.The colonization of the Hawaiian Islands by the ancestral species that radiated to produce the Hawaiian honeycreepers could have occurred at any time between 20 and 5 million yr ago. Because the honeycreepers captured so many ecological niches, however, it seems likely that their ancestor was the first passerine to become established in the islands and that it arrived there at the time of, or soon after, its separation from the cardueline lineage. If so, this colonist arrived before the present islands from Hawaii to French Frigate Shoal were formed by the volcanic "hot-spot" now under the island of Hawaii. Therefore, the ancestral drepaninine may have colonized one or more of the older Hawaiian Islands and/or Emperor Seamounts, which also were formed over the "hot-spot" and which reached their present positions as the result of tectonic crustal movement. The cardueline-drepaninine lineage probably diverged from the Fringilla lineage in the late Oligocene, from the New World nine-primaried oscines in the early Oligocene, and from the other oscines in the early Eocene.During this study we also obtained evidence that the vireos (Vireonidae) are not closely related to the New World nine-primaried oscines.

The technique of DNA-DNA hybridization was used to compare the nuclear DNAs of the Brown Treecreeper Climacteris picumnus and the Rufous Treecreeper Climacteris rufa with the DNAs of other passerine taxa. The treecreepers were found to be the descendants of the oldest dichotomy (ca. 45-48 MYA) in the superfamily Menuroidea, a group that also includes the lyrebirds, scrub-birds, and bowerbirds. We recognize the family Climacteridae, superfamily Menuroidea, parvorder Corvi, suborder Passeres. Within the Climacteridae we recognize two genera, Climacteris for the species picumnus, rufa, melanura, erythrops, and affinis, and Cormobates for leucophaea (including minor) and placens.

The taxonomic relationships of two Bornean endemics,Pityriasis gymnocephala andChlamydochaera jefferyi, have been considered to be uncertain. DNA-DNA hybridization was used to compare the single-copy sequences of each of these two species with other passerine taxa. The DNA data support other evidence indicating thatPityriasis is a cracticine corvoid, most closely related to the Australo-Papuan generaCracticus, Gymnorhina, Strepera, andPeltops. Chlamydochaera is a typical turdine thrush, closely related toTurdus. This supports and confirms the morphological evidence presented byAmes (1975).Chlamydochaera is not related to the cuckoo-shrikes (Campephaga, etc.) of the Tribe Oriolini.

Most avian systematists of the past century have thought that the accentors(Prunella) are most closely related to the thrushes (Turdinae). A few have favored the fringillids, and others have suggested the sylviids, parids, troglodytids, motacillids, mimids, cinclids or timaliids as close relatives ofPrunella. Comparisons were made between the single-copy DNA sequences of the Dunnock(Prunella modularis) and those of 28 other species of Passeres representing all major groups of oscines. The ploceine finches were found to be most closely related toPrunella and the next nearest relatives include the motacillids, sunbirds,Passer, and the fringillids. These groups are members of the superfamily Fringilloidea. The thrushes, starlings, mockingbirds, muscicapine flycatchers, and dippers (= Muscicapoidea); the sylviine warblers, babblers, and tits (= Sylvioidea), and the monarch flycatchers, wrens, larks, waxwings, and Australian scrub-robins(Drymodes), are not closely related toPrunella.

of Hubby and Lewontin (1966) and Lewontin and Hubby (1966), there has been considerable interest in determining the percentage of the genome that may be either heterozygous in individuals or polymorphic in populations. Comparable data for natural populations of many species, both vertebrates and invertebrates being represented, are now available. However, the extent of protein polymorphism and individual heterozygosity in natural avian populations is known for relatively few species (Bush 1967; Sibley and Corbin 1970; Nottebohm and Selander 1972). Several other studies of protein polymorphism in bird populations have dealt with only a few loci (Stratil and Valenta 1966; Brush 1968, 1970; Bush et al. 1970; Ferguson 1971; Brush and Scott 1972). Most of the work on the specific variation of bird proteins involved domestic species. In this category, proteins found to be polymorphic include the serum esterases of the Japanese Quail (Coturnix coturnix) (Kaminski 1964; Manwell and Baker 1969), several species of pigeons (species of Columba and ALAN H. BRUSH

The living species of flamingos form a small, easily defined group of three genera, Phoenicopterus, Phoeniconaius, and Phoenicopawus. Phoenicopterus is usually divided into three forms, considered to be species by some authors while others treat them as races of the Greater Flamingo, Phoenicopterw Tuber. These are P. T. Tuber of the New World tropics and subtropics, P. r. chilen&.s of temperate South America, and P. T. roseus (= antiquorum) of the Old World. The Lesser Flamingo; Phoeniconaius minor, occurs in Africa and India and Phoenicoparrus an&us and P. jamesi are confined to the Andes in Peru, Argentina, and Chile. These four (or six) living species are the survivors of a long and well-documented lineage extending at least to the early Tertiary and possibly into the Cretaceous. In spite of this unusually good fossil record the relationships of the flamingos to other groups of birds have been difficult to determine beyond doubt. A large body of evidence, mainly anatomical, suggests an alliance to the Ciconiiformes (herons, storks, ibises), but the bill and feet, development of the young, the voice, and the mallophagan parasites have been interpreted as indicating an origin from the Anseriformes ( ducks, geese). The question is, are the flamingos most closely related to the herons and storks and merely convergent to the anseriform birds in certain characters or were they derived from the ducks and geese and later converged toward the ciconiiform birds? A third possibility is that they were derived from some other group and are similar to both geese and herons only by convergence. In this paper we will review various opinions about the classification of the flamingos, the fossil history, and the anatomical, behavioral, and other evidence which has been presented. We will then present some new data from our studies of the egg-white proteins and hemoglobins of birds which bear upon this problem.

relationships has led to the study of many characters. In addition to comparative morphology some systematists have utilized ecology, behavior, serology, and biochemistry as clues to the degrees of genetic relatedness among organisms. Because protein molecules are primary gene products it is logical to assume that comparisons among homologous proteins from different organisms should provide useful systematic data. The rationale behind this approach to systematics has been discussed by several authors including Sibley (1960, 1962, 1964, 1965, 1967), Zuckerkandl and Pauling (1965), and Dessauer (1969). The plasma proteins are an obvious choice for investigation because they are easy to collect and because a great deal is known about their properties and functions. Plasma is the fluid portion of blood in which the blood cells are suspended. It is a complex mixture of proteins, carbohydrates, lipids, steroids, and free ions whose composition varies with sex, age, starvation, season, etc. (Moore 1948; Clegg et al. 1951; Vanstone et al. 1955; Dessauer and Fox 1956; Saito 1957b). The protein constituents of plasma, while often quantitatively variable, usually show a high degree of qualitative species specificity when examined by any standard biochemical technique (Morris and Courtice 1955; Zweig and Crenshaw 1957; Drilhon et al. 1958; Woods et al. 1958; Sulya et al. 1961). Some of these studies were based upon serum, the fluid portion of the plasma which is extruded from a blood clot. Plasma thus contains the blood proteins involved in clotting while serum lacks them. Most of the research on plasma proteins has dealt with human material although there has been a great deal of work on other mammalian species and the domestic fowl, Gallus gallus. The major protein components of plasma are albumin, the alpha-, beta-, and gamma-globulins, and various subfractions thereof. The nomenclature of the various components is usually determined by their electrophoretic mobilities with reference to normal human plasma. Thus, albumin is the fastest fraction, alpha-globulin the next fastest and gammaglobulin the slowest. The identification of plasma proteins under different conditions can be difficult (Espinosa 1961; Beaton et al. 1961). Up to 70 different proteins have been found in normal human plasma (Dessauer and Fox 1964) while Baker et al. (1966) found 40 electrophoretic bands in pheasant serum, 14 of which were identifiable. The review by Putnam (1960) provides information on the chemical composition of plasma. In paper electrophoresis at pH 8.6 the fastest c mponent in human plasma is albumin. It has a molecular weight of about 69,000 and is is electric at pH 4.7 (Phelps and Putnam 1960). It may be assumed that the values for other mammals and for birds are similar (Phelps and Putnam 1960:169). Plasma albumin has the same chemical properties as alpha livetin of egg yolk (Williams 1962a) but it has no known specific biological functions (Foster 1960). There are several alpha-globulins, which presumably have different functions. The best known are the hemoglobin-binding haptoglobins and the copper-binding ceruloplasmin. Human haptoglobin has a molecular weight of 85,000 and it is isoelectric at pH 4.1, while ceruloplasmin has a molecular weight of 151,000 and is isoelectric at pH 4.4 (Phelps and Putnam 1960). There are several discrete beta-globulins, most of which have unknown functions. The best known of these are the transferrins. Tra sferrin, also called siderophilin, is an ironbinding protein with a molecular weight of approximately 90,000; it is isoelectric at pH 5.9 (Phelps and Putnam 1960). It has been found that the protein moiety of the transferrin molecule is identical to that of the conalbumin of egg white. They differ only in their 1 Present address: Department of Biology, University of North Carolina at Greensboro, Greensboro, North Carolina 27412.

IT IS appropriate that the views of ornithologists should be represented in this symposium because it was an ornithologist who first used trinomials to designate geographic races; it was primarily the ornithologists in this country who first espoused the concept, and it has been, I regret to say, in considerable measure due to the efforts of a few ornithologists that the subspecies has fallen into disrepute. It was Hermann Schlegel, as the coauthor with C. J. Temminck of the Aves section of Siebold's Fauna Japonica published in 1844, who first applied a trinomial combination to designate geographic subdivisions of species. There were few proponents of this system in Europe at first, but Baird, Coues, and Ridgway in the United States adopted it and applied the triple combination to geographic races. Coues even went to England in 1884 and in an historical meeting at the British Museum he tried to persuade the leading British avian taxonomists of the time to adopt the trinomial system. He was supported by Henry Seebohm but rebuffed by such potent adversaries as P. L. Sclater and R. Bowdler Sharpe. One result of this defeat was the adoption of the Code of Nomenclature of the American Ornithologists' Union in 1885. The watchword of the time was "Intergradation is the touchstone of trinominalism." By 1912, following the deaths of Sharpe and Sclater and the increasing influence of Ernst Hartert, the subspecies became as entrenched in Europe as it was in this country. It may be that history is not our purpose here but it seems apparent that the transition from the strict application of binomials to that of trinomials contains many parallels to the present situation. The problems which confronted our predecessors in systematic zoology are remarkably similar in kind, although different in degree, to those which face us today. Before attacking the subspecies concept too vigorously let us examine history once more for evidence as to its causes, its effects, and its values. In the century between Linnaeus and Darwin species were regarded as comfortably immutable and collections were still too limited to demonstrate the true range of individual and geographic variation. By 1859, when Darwin provided the theoretical basis to explain such variability, collections were extensive enough to reveal it, and Schlegel and others had indicated a method for its nomenclatorial recognition, namely, the trinomial. A modification in nomenclatorial practice was inevitable if Darwinism was to be applied. As late as 1909 Sharpe retained the Linnaean binomial in his Handlist and thereby emerged with a count of over 19,000 "species" of birds in the world. The enormous difference between this figure and the 8,600 computed by Mayr and Amadon in 1951 is an index to the differences in viewpoint of the authors and their times. We are today in a position curiously parallel to that of systematists during the transition from binomialism to trinomialism. Let us approach the present problem with an understanding of the historical background as well as of its biological significance, for it is probable that Coues and