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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.

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.

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.

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.

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.

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.

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.

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.

In 1858 Baird (Pac. R. R. Repts., vol. 9, p. 336) designated the warbling vireos of the western United States as Vireo swainsonii. The Great Basin form was separated as Vireosylva gilva leucopolia by Oberholser in 1932 (Sci. Publ. Cleveland Mus. Nat. Hist., vol. 4, p. 9). From the mountains of Chihuahua, Ridgway described Vireosylva gilva brewsteri (Proc. Biol. Soc. Wash., vol. 16, 1903, p. 107). Within the past year van Rossem (Trans. San Diego Soc. Nat. Hist., vol. 9, 1940, pp. 77-78) has named Vireo gilvus connectens from the state of Guerrero in southern Mexico, and Sutton and Burleigh (Auk, vol. 57, 1940, pp. 398-400) have described Vireo gilvus eleanorae from Hidalgo in central eastern Mexico. These three races from the mainland of Mexico constitute an integrating series that establishes Ridgway's belief that the leucophrys and amauronotus groups of vireos of Central and South America are conspecific with gilvus. Breeding birds from the Cape Region of Lower California prove to be another link in this chain. Relationship to the southern forms is shown by the admixture of brown in the back, and that to the races of the United States by the almost immaculate underparts. The differences are sufficient to warrant separation as a distinct race.

A study of the variation in plumage pattern and coloration in hybridizing orioles of the genus Icterus indicated that the two subspecies of the northern oriole, Icterus galbula galbula and I. g. bullockii, are sympatric in at least one locality in the Great Plains of North America (Corbin and Sibley, 1977). The genetic variation at 19 loci of the birds collected in that study is presented here. The observed allelic frequency differences are used to document further those changes that appear to be taking place in, and adjacent to, the zone of overlap and hybridization between the galbula and bullockii subspecies of the northern oriole. The observed sympatry between these two currently recognized subspecies might be a transient local condition resulting from a chance influx of the galbula phenotype into the range of distribution of the bullockii phenotype. However, we believe the evidence available supports the hypothesis that sympatry between the two subspecies has an underlying genetic basis, that sympatry developed in situ as a result of assortative mating and not because of rare dispersal events. As such,the condition may provide a better understanding of the genetic changes associated with the intermediate stages of the speciation process. We approach our hypothesis by considering: 1) how the allelic frequencies within and outside of the zone of contact might be altered following secondary contact between hybridizing, differentiated subspecies, and 2) how allelic frequencies might change within the zone of hybridization subsequent to selection against hybrids. Hybridization involving the orioles of the genus Icterus was first recognized by Sutton (1938) and subsequently studied in detail by Sibley and Short (1964), Sutton (1968), Rising (1968, 1969, 1970, 1973), Anderson (1971), Misra and Short (1974) and Corbin and Sibley (1977). In the mid1950s, the Baltimore oriole, Icterus galbula, and the Bullock's oriole, I. bullockii, were recognized as species. Morphologically, they could be distinguished on the basis of plumage pattern and coloration as well as on the basis of mensural characteristics such as wing length, tail length and body length. However, hybridization between them was extensive throughout the Great Plains of North America (Sibley and Short, 1964). Within the hybrid zone the average value of each of the various traits was intermediate between those of the parental phenotypes. (We use the term "hybrid zone" as defined by Short [1969:89], an area of hybridization where only hybrids occur, as distinguished from a "zone of overlap and hybridization" which is an area of secondary intergradation occupied by numerous hybrids and both parental forms.) There was evidence that introgression was bidirectional and that hybrid progeny were equally fit in comparison to the offspring of pure parental matings, although the latter was an inference based on the frequency of hybrids rather than on experimental breeding data. It appeared that premating isolating mechanisms were ab

In the preceding chapter in this volume, Cracraft has posed a series of questions concerning our application of the technique of DNA—DNA hybridization to the reconstruction of the phylogenetic relationships among living birds. Our purpose is to respond to Cracraft’s questions, to correct misunderstandings, and to reaffirm our confidence in DNA hybridization as a valuable and effective method for the reconstruction of phylogenies.

first specimens to be recognized as hybrids were described by Sutton (1938), and the zone of hybridization has been studied by Sibley and Short (1964), Rising (1968, 1969, 1970, 1973), Anderson (1971), and Misra and Short (1974). The specimens collected during the 1950's by Sibley and Short (1964) indicated that the parental forms were behaving biologically as subspecies. As clarified by Short (1969), the parental types were allopatric and separated by a hybrid zone. At that time there was no zone of overlap and hybridization, within which both parental types existed in sympatry and in a combined frequency greater than 5% of the total population. That is, there was no apparent reinforcement of isolating mechanisms. In 1973 the A.O.U. Check-list Committee accepted the recommendation by Sibley and Short (1964) that the western forms (bullockii) be treated as subspecies of I. galbula. This decision was based primarily on birds collected along the Platte River, extending from Greeley, Colorado to Blair, Nebraska. However, Rising (1968, 1970) believed that the "Bullock's Oriole" and "Baltimore Oriole" should not be

The relationships of the Wrentit (Chamaea fasciata) have been debated since its discovery in 1845. The titmice (Parus), babblers (Timaliini), Old World warblers (Sylviini), bushtits (Psaltriparus), wrens (Troglodytidae), and mockingbirds (Mimini) have been suggested as its closest relatives. Many authors have placed the Wrentit in a monotypic family, Chamaeidae. DNA-DNA hy- bridization comparisons between the homologous nucleotide sequences of the single-copy DNAs of the Wrentit and other passerines indicate that Chamaea is most closely related to the babblers and the Old World warblers, and that the latter two groups are ecotypes of a single, varied, monophyletic assemblage. The Wrentit is annroximatelv eauidistant from the sylviines and the timaliines, but ecologically it is a babbler. _ The Wrentit (Chamaea fasciata) occurs in chaparral and other dense, brushy, plant for- mations in western Oregon, California, and northwestern Baja California. The question of its affinities to other passerines has been de- bated since the 1850's. Sibley (1970:57-60) reviewed the taxonomic history of the Wrentit and presented electrophoretic comparisons between its egg white proteins and those of many other oscine taxa. He concluded that the total evidence did not offer a clear choice be- tween the sylviine warblers and the timaliine babblers as the closest relatives of Chamaea and that the question of the "relationships of the wren-tit remains open and further evidence should be presented before the affinities of the wren-tit are considered to have been proved beyond doubt" (p. 60). More recently, Sibley and Ahlquist (1980) concluded that Cha- maea is a babbler. In the present paper we offer additional data showing that the sylviine warblers and timaliine babblers are actually ecotypes of a single varied assemblage and that the Wrentit probably was derived from an Asiatic babbler. METHODS

The Sharpbill (Oxvruncus cristatus) is a Neotropical suboscine passerine whose affinities have been unclear. The tyrant flycatchers, cotingas, and manakins of the superfamily Tyrannoidea have been suggested as the closest relatives of the Sharpbill. DNA-DNA hybridization comparisons between the radioiodine-labeled single-copy DNA of the Sharpbill and the DNAs of cotingas, manakins, tyrant flycatchers, and representatives of the other Neotropical superfamily, the Furnarioidea, indicate that Oxyruncus is a cotinga. We place it in the subfamily Cotinginae, family Tyrannidae. The Sharpbill (Oxyruncus cristatus) is a medium-sized (ca. 16 cm) suboscine passerine with a straight, pointed bill and short rictal bristles. In the adult male the crested crown has a crimson center bordered by olive feathers tipped with black. The back is bright olivegreen, wings and tail blackish, underparts white with black spots, and the flanks pale greenishyellow. The plumage colors of the adult female are less intense than those of the male and the coronal stripe is inconspicuous. The Sharpbill apparently has a discontinuous range in the humid montane forests of Costa Rica, Panama, southeastern Venezuela, southern Guyana and Surinam, northeastern and southeastern Brazil, southern Paraguay, and central Peru (Mees 1974, Traylor, 1979). Extensive field observations of the Sharpbill have not been recorded but Sick (197 1) reviewed the sparse literature and reported on his encounters with the species during his many years of field studies in Brazil. He found that Sharpbills tend to occur most often in dense tall forest, although they sometimes feed on fruits at the forest edge or in solitary trees. Fruits are the principal food but insects have been found in the stomachs of specimens and Sick observed Sharpbills hanging upside down from twigs to capture insect larvae. The vocalizations are relatively simple and similar to those of certain cotingas. Sick found the birds most often in pairs and in mixed flocks of tanagers, furnariids, troupials, cotingas, woodpeckers, etc. feeding on fruiting trees. A captive Sharpbill ate fruits and cast hard pellets composed of the skins. Bangs and Barbour (1922) also observed Sharpbills feeding in fruiting trees with cotingas; Mees (1974) found them solitary, in pairs, and in mixed bird swarms in Surinam. Wetmore (1972:605) saw “four or five” together in Panama and recorded spiders, ants, and seeds from stomach contents. Brooke et al. (1983) found the first recorded nest of the Sharpbill near the top of a 30-m tree in the montane forest of the Serra do Tingua, 50 km north of Rio de Janeiro, Brazil. The nest, which was built by the female, was “saddled onto a slender (ca. 3 cm) horizontal branch” and was a “simple . . . shallow cup . . . composed of roughly interlaced leguminous petioles . . . and a very few dry leaves.” The outer surface “was a thin coat of mosses, liverworts, and spider’s web. . . with a texture akin to thin cardboard, possibly resulting from the application and subsequent drying of saliva.” The female fed the young by regurgitation, as do cotingas, rather than as in insectivorous tyrannids. Brooke et al. (1983) observed adult Sharpbills feeding in the ways described by Sick (1971).