De Schauensee Research Articles

The avifauna of Biak Island, Papua, Indonesia with comments on status, conservation, natural history and taxonomy

New Guinea and its satellite islands are justly renowned for their spectacular and highly diverse, endemic avifauna. The oceanic island of Biak and its satellites, in Teluk Cenderawasih (formerly Geelvink Bay), Papua province, Indonesia, has an avifauna of c.159 species including the largest number of endemics of any island in the New Guinea region: seven species are strictly endemic to Biak and another six are shared with other Teluk Cenderawasih islands but not Yapen. Despite Biak attaining an elevation of c.1,034 m there are no species whose range on Biak is known to be entirely montane. We provide a physical description of Biak and its twin Supiori, and discuss the biogeography and conservation of their birds. We present a detailed checklist of all species recorded to date. Since the publication in 1939 of Mayr & Meyer de Schauensee, 66 species have been added to the Biak list, of which Short-eared Owl Asio flammeus and Black-winged Stilt Himantopus himantopus are new for the entire Australo-Papuan region and Grey Heron Ardea cinerea only the second for the region and first for New Guinea; 47 of these additions are also first records for any island in Teluk Cenderawasih. An appendix summarises the distribution and status of birds in Teluk Cenderawasih (excluding mainland New Guinea species only on Yapen).

Rediscovery of the holotype of the American Goshawk, Accipiter gentilis atricapillus (Wilson, 1812), and a commentary about Alexander Wilson's contributions to the Peale Museum

Alexander Wilson (1766–1813) based his description of the “Slate-colored Hawk / Falco atricapillus” (=Accipiter gentilis atricapillus) on a single specimen collected near Philadelphia, Pennsylvania, which he deposited for posterity in the Philadelphia (Peale) Museum. Wilson's illustration of the specimen was engraved and hand-colored prints were published in American Ornithology vol. 6 (1812b, Pl. 52) to accompany his scientific description of the species. However, the path of Wilson's type specimens became difficult to trace after the Peale Museum closed in 1846 and its collections were sold and dispersed. Wilson's holotype of F. atricapillus was presumed lost or destroyed until November 2020, when I rediscovered it in the collection of the Academy of Natural Sciences of Drexel University (ANSP), thanks to a penciled note made by the late Rodolphe Meyer de Schauensee, former ANSP curator of birds. This research also sheds new light on the history of the Peale Museum bird collection, exposing a basic misunderstanding about the “Peale numbers” cited by Wilson, which has broad implications for the history of American ornithology. In short, “Peale numbers” were assigned to species (not specimens) held in the Peale Museum.

Which large species of seed finch occurred on Trinidad?

A population of large seed finches, probably extirpated, occurred on Trinidad. Studies of specimens by Phelps & Phelps and by Meyer de Schauensee identified this population as the taxon now known as Sporophila maximiliani parkesi, but subsequent literature has often referred to these birds as S. c. crassirostris without fresh evidence or analysis. My review of specimens reaffirms their identity as S. m. parkesi, and refutes the hypothesis that this taxon should be considered a synonym of S. m. maximiliani.

Scientific encounters between Colombia and the United States analyzed through publishing practices in Caldasia journal: The birds of the Republic of Colombia as a publishing event

In 1948, American ornithologist Rodolphe Meyer de Schauensee began publishing what would be the most complete list of birds from Colombia that had ever been printed up to that time. His work was called The Birds of the Republic of Colombia (TBRC), and at the invitation of Armando Dugand, the director of the Instituto de Ciencias Naturales at the Universidad Nacional de Colombia and of the Caldasia journal, this work was exclusively published in the journal in five installments spanning four years. This paper analyzes the publishing aspects that particularly influenced the process of carrying out this work, with the objective of showing that scientific practices and publishing practices are not two absolutely separate domains. The circuit of communication present in TBRC's development is analyzed, specifically the efforts of the editor, printer and author to bring this work to fruition. This analysis demonstrates the following: (i) how the scientific interests of Meyer and the Instituto de Ciencias Naturales converge, (ii) the contradictions between scientific interests that promoted the publication of TBRC and the publishing rationale of a journal and (iii) how unforeseen publishing issues of the time, such as the increase in printing costs due to inflation, influenced the final structure of the work.

A note on bit types at Hasanlu, Iran

Hasanlu Tepe is a large mounded site in the Solduz Valley of western Azerbaijan dating from Islamic to Neolithic times. One of its main occupation levels belonged to the Iron II period (Fig. 1). This settlement was sacked and burned around 800/780 BC, preserving a large quantity of objects of daily living in the collapsed buildings (Dyson and Voigt 1989). One building (BB II) is thought to have been a temple (Dyson and Voigt 2003). Two others (BB IVE and BBV) appear, from the presence of urine stains and horse skeletons, to have been in use as stables at the time of the destruction, converted from an earlier function. They, as well as other areas, contained horse gear as well as skeletons of horses (de Schauensee and Dyson 1983; de Schauensee 1988: 47–9; 1989). Two types of bits for horses were found. Comparisons between them, combined with associated material, suggest that they had distinct, non-overlapping functions.

Two Lyres from Ur. By Maude de Schauensee. Philadelphia: University of Pennsylvania Museum of Archaeology and Anthropology, 2003. Pp. xix + 125 + 8 figs. + 51 pls. $29.95 (cloth).

<i>Two Lyres from Ur</i>. By Maude de Schauensee. Philadelphia: University of Pennsylvania Museum of Archaeology and Anthropology, 2003. Pp. xix + 125 + 8 figs. + 51 pls. $29.95 (cloth).

Book Reviews

Book reviewed in this article:Guide to the Mesoamerican Gallery at the University of Pennsylvania Museum of Archaeology and Anthropology, elin danien.Collectors: Individuals and Institutions, anthony shelton, ED.Two Lyres from Ur. maude de schauensee.Adventures in Photography: Expeditions of the University of Pennsylvania Museum of Archaeology and Anthropology. alessandro pezzati.

Skeletons and the Genera of Sparrows (Emberizinae)

Based on comparisons of skeletons from 228 species of sparrows (Emberizi- nae), we detected 24 characters that were useful for generic separations. Of these, 19 quan- titative characters were used in a detrended correspondence analysis (DCA) ordination. Presence or absence of a lacrimal bone, degree of inflation of the squamosal area, length of the lateral process of the laterosphenoid, ratio of ulna length to femur length, length of the skull, and premaxilla length-to-width ratio were the most informative characters. The first two axes of the DCA clearly grouped most genera. Based on our analysis of these skeletal characters, we recommend the following changes to the classification of Paynter (1970): Spo- rophila obscura belongs in Tiaris; Emberizoides ypiranganus is a valid species; Pselliophorus and Pezopetes should be lumped with Atlapetes; and Torreornis and Oriturus should be lumped with Aimophila. In addition, a different sequence of genera should be adopted. Two groups of genera are distinct: seedeaters and North American sparrows. A third group, South Amer- ican grassland finches, overlaps with the first two groups. Received 17 February 1998, accepted 15 March 1999. THE SUBFAMILY EMBERIZINAE constitutes a large (279 species in 65 genera) group of song- birds adapted for eating seeds during at least part of the year. Most spedes occur only in the Western Hemisphere, but two are Holarctic, and four genera are confined to the Eastern Hemisphere. The last comprehensive classifi- cation of the Emberizidae was by Sharpe (1888), although Ridgway (1901) characterized the North and Middle American forms and some of the South American genera. Hellmayr (1938) listed all of the Western Hemisphere forms, noting the characters of some genera. Vaurie (1959) and Cramp and Perrins (1994) re- viewed the Eurasian species, and Meyer de Schauensee (1970a) and Ridgely and Tudor (1989) listed the South American species and provided characterizations. Hall and Moreau (1970) reviewed the African species. Paynter (1970) listed all of the forms and their geo- graphic ranges in the most recent complete classification based on spedmens, but he did not include characterizations; we follow his classification in this paper except where noted otherwise. Sibley and Monroe (1990) listed the genera and species with their ranges; they did not include characterizations, and their classi- fication was based on DNA-DNA hybridization studies (Sibley and Ahlquist 1990) of 22 (34%) genera and 24 (9%) species. Sibley and Mon-

The Little Gull Larus minutus in Japan.

The Little Gull Larus minutes, the world's smallest gull, breeds in thr regions in the U. S. S. R., the easternmost region covering Transbaikal and southern Yakutia east to the Okhotsk Sea (Flint et al. 1984). It is a long distance migrant, and all three populations according to Flint et al. (1984) winter on the shores of western Europe, the Black and Caspian Seas. In China it is a straggler only in winter to Heilungkiang, Kiangsu and west Sinkiang provinces (De Schauensee 1984). De Schauensee (1984) however regarded it as also wintering in the Sea of Japan, as did Harrison (1985) who also indicated a winter range incorporating the Pacific Ocean off Japan. Both statements, however, may have been based on supposition, since there appears to be no actual evidence for east Asian wintering ground. If as suggested by Harrison (1985) and De Schauensee (1984) the Little Gull did winter in the Sea of Japan it would surely have been reported regularly, if not commonly, from South Korea and Japan, but in fact it has not. There are no (?) records from the Korean Peninsula and it had not been reported from Japan prior to 1974 (see Austin & Kuroda 1953, Ornithological Society of Japan) and sinee 1974 only two records have been noted from Japan surprisingly neither of which was from the Sea of Japan (Brazil in press). The paucity of records suggests that both Harrison (1985) and De Schauensee (1984) are incorrect.

The First Spring Record of a Shore Lark Eremophila alpestris from Japan.

The Shore Lark Eremophila alpestris breeds along the entire northern coast of the U. S. S. R. east to just beyond the mouth of the Kolyma River, and an inland population breeds east to just beyond the Aldan River (Flint et al. 1984). Nowhere does its breeding range reach the Pacific or Okhotsk Sea coasts. Birds breeding in the northeast of the U. S. S. R. migrate south to southen parts of the U. S. S. R. and to China. In China it is both a resident and a migrant with birds of the race flava (the subspecies recorded in Japan), which also breeds in the U. S. S. R. wintering from Hubei Province to eastern Inner Mongolia and breeding as far east as Heilongjiang Province (De Schauensee 1984).

Suggested changes to the English names of some Western Palearctic birds

Suggested changes to the English names of some Western Palearctic birds

The Birds of China, by Rodolphe Meyer de Schauensee [Review

The Birds of China, by Rodolphe Meyer de Schauensee [Review

Iridescent polychromatism in a female hummingbird: is it related to feeding strategies?

Iridescent polychromatism in a female hummingbird: is it related to feeding strategies?

Distributional Changes in the Colombian Avifauna: A Preliminary Blue List

Some important man-caused changes in the distributions of Colombian bird populations are discussed. Examination of the changes is based on a preliminary Blue List of 135 species with declining populations. Canopy frugivores dominate the list, followed by terrestrial and aquatic species, respectively. There are proportionately more highland species on the list than lowland species. Two regions, the central Colombian highlands, and the Cauca-Magdalena lowlands contain more declining species than other avifaunal regions. Almost two-thirds of Colombia's endemic species have been placed on the list. Some species have profited from deforestation or other human activities, and these are discussed. RESUMEN. Se discuten algunos cambios importantes, causados por el hombre, en las distribuciones de poblaciones de aves colombianas. El reconocimiento de los cambios esta basado en la Lista Azul preliminar de 135 especies con poblaciones en disminuci6n. Los frugivoros del tope del bosque dominan la lista, seguidos respectivamente por especies terrestres y acuaticas. Proporcionalmente en la lista hay mas especies de tierras altas que de tierras bajas. Dos regiones, las tierras altas del centro de Colombia y las tierras bajas de Cauca-Magdalena, presentan mas especies en disminucion que otras regiones de avifaunas. Casi dos tercios de las especies endemicas de Colombia estan incluidas en la lista. Se discute tambien la ganancia que obtuvieron otras aves por la deforestation y otras actividades humanas. In this paper I examine changes in the distributions of Colombian bird populations. Olivares (1970) and Lehmann (1970) discussed some effects of environmental change on birds in Colombia and mentioned examples of species that have profited or been harmed by these changes. However, neither author attempted to provide a comprehensive overview of the country's avifauna. Some of Colombia's endangered or threatened species are discussed in the International Council for Bird Preservation (ICBP) Bird Red Data Book (King 1981). Unfortunately, little other information has been compiled on distributional changes of Colombian birds. Furthermore, bird populations in Colombia (or most anywhere in developing regions of the world) are not systematically surveyed or evaluated like they are through the Blue List for North America (Arbib 1971), the Christmas Bird Counts, or more recently the natural heritage inventories of The Nature Conservancy. There is no systematic research on endangered Colombian species either by government or private agencies. In order to examine distributional changes in Colombia's avifauna a preliminary Blue List was prepared. This list is similar in concept to that initiated in North America in 1971 by Robert Arbib (Arbib 1971). The latter list, updated annually, includes North American birds that are of special concern because they appear to be ... giving indications of non-cyclic population decline or range contractions, either locally or widespread (Arbib 1971). Species on the list may be fairly common locally, or even widespread, but because of habitat reduction, chemical contamination, hunting pressure, or other causes, their populations appear to be in decline. As noted by Arbib (1971, 1972) the Blue List is essentially an early warning system that focuses attention on problem species and may help alert the scientific community, government agencies, and the public to situations where action is needed. I include on the present list (Table 1) most species whose geographical ranges in Colombia are believed to have declined by at least 50 percent. Unlike the North American Blue List, I also include all endangered species listed by the ICBP Bird Red Data Book (King 1981) because information on these species is scarce. I exclude species known only from one or a few localities near the Colombian border, or species known only from Bogota specimens without precise locality (Meyer de Schauensee 1 948). I also exclude a considerable number of species whose ranges probably have contracted by 50 percent or more due to deforestation since pre-Colombian times but that still occur commonly wherever tracts of forestland remain. Examples of species in this

Notes on Siptornis striaticollis (Furnariidae) in Peru

The Spectacled Prickletail (Siptornis striaticollis) is a monotypic furnariid previously recorded only from the subtropical zone of the middle and upper Magdalena Valley in Colombia and the east slope of the Ecuadorian Andes (Mapoto) (Chapman, Bull. Am. Mus. Nat. Hist. 36, 1917; Chapman, Bull. Am. Mus. Nat. Hist. 55, 1926). In view of the paucity of information on Siptornis, we offer the following observations and report the first occurrence of the species in Peru. In 1978, during ornithological investigations in the Department of Cajamarca in northern Peru, we found Siptornis striaticollis northeast of Huancabamba, ca. 2 km south of Carmen, on the Sapalache-Namballe mule trail (OSOS’ S, 7922’ W). We saw these birds daily from 2 to 17 July foraging with large mixed-species flocks in patches of cloud forest between 1,660 m and 1,880 m elevation. Occasionally when a mixed-species flock assembled in an isolated cluster of trees, we made exact counts of arriving and departing individuals. Siptornis was a regular, low-density participant, with a maximum of three to four individuals per flock. Common flock members included the furnariids Crunioleuco curtata, Anabacerthia striaticollis, and Xenops rutilans, and the antwren Terenuru callinota. The prickletails foraged by creeping along branches, and probing moss clumps, clusters of dead leaves, fruticose lichens, and bark crevices at the level of the forest subcanopy and edge 5-15 m above ground. Several times individuals were seen hanging “paridlike” from petioles of Cecropia leaves, picking unidentified food items from undersides of leaflets. Among species that occur in the same area, Siptornis most closely resembles Xenops rutilans in behavior, size, coloration, and plumage pattern. Both Siptornis and Xenops tapped sporadically on limbs, often bracing the tail against the bark when probing deep crevices. During light rain or dense fog we often located these birds by their faint tapping sounds. On 9 July, after watching a large mixed-species flock pass over the trail, Eley heard a peculiar high-pitched trill coming from the top of a nearby bush. Immediately afterward, a Siptornis hopped into view and perched upright in the bush about 2 m above the trail. Another motionless individual about0.5 m from the first bird and in the interior of the bush answered the trill with a similar call. We heard no other vocalizations of this species. Siptornis striaticollis appeared most closely to fill the ecological niche of piculets of the genus Picumnus. In most subtropical cloud forest throughout eastern Peru and Bolivia at least one species of piculet occurs (Meyer de Schauensee, A guide to the birds of South America, Livingston Publ. Co., Wynnewood, Penn., 1970, and pers. observ.), but piculets are unknown in subtropical forest in the eastern Andes north of the Mararion River, where Siptornis occurs. Perhaps Siptornis and Picumnus are ecologically incompatible. Our three specimens, all males, are deposited at the Louisiana State University Museum of Zoology (LSUMZ). Data from these specimens are listed in Table 1. We thank Richard D. Semba and Manuel Sanchez S. for field assistance. J. Van Remsen, H. Douglas Pratt, John P. O’ Neill, and John Weske read the manuscript. We are most grateful to John S. McIlhenny and Babette M. Odom for their generous support of the field work of the LSUMZ.

The Dwarf Cuckoo in Venezuela

The Dwarf Cuckoo (Coccyzus pumilus) is a poorly known species; the only detailed observations of its breeding biology were made near Cali, Colombia by Ralph (Condor 77:60-72, 1975). Meyer de Schauensee (The species of birds of South America with their distribution, Livingston Publishing Co., Narberth, Pa., 1966) reported it as found in parts of Colombia and Venezuela in tropical and occasionally subtropical zones. Phelps and Phelps (Lista de las aves de Venezuela con su distribucion, Tomo 2, Parte 1, Bol. Soc. Venez. Ciencias Nat., 19, No. 90, 1958) described it as very locally distributed in Venezuela. I made the following observations on Fundo Pecuario Masaguaral, a cattle ranch in the state of Gu~irico, central Venezuela. This ranch is in the Venezuelan Ilanos, an extensive low-altitude grassland with scattered trees and occasional gallery forests. The habitat is designated as dry tropical woods by Ewel and Madriz (Zonas de vida de Venezuela, Ministerio de Agricultura y Cria, Republica de Venezuela, 1968). The llanos have a highly seasonal hydrology; rains from May through October flood the ground in places to a depth of over 50 cm; the other six months of the year are extremely dry. On the morning of 19 July 1973, I observed a Dwarf Cuckoo perched in some dense thorny bushes surrounding the base of an isolated palm tree in an area where the seasonal water was more than 30 cm deep. While preening, the cuckoo occasionally uttered a five to six note rattling churr. This call resembles a portion of the vocal duet of the White-bearded Flycatcher (Myiozetetes inornata), a permanent resident of the area. Another cuckoo answered briefly from the far side of the bushes. Ralph interpreted this call as a pair contact. The preening bird made another sound at about 11-sec intervals, a low single click which was accompanied each time by a shake of its body. Probably this is the same vocalization characterized by Ralph as cluck or tok. Later I found a nest in the same bushes, but on the side facing an open marsh. It was placed in a horizontal crotch of thorny branches at a height of 2 m. The nest was about 18 cm in diameter and constructed of small sticks so loosely put together that sky could be seen through it. A young cuckoo crouched on the supporting branch beside the nest. The juvenile cuckoo had a pale gray head and nape, and light brown back, wings and tail. Below, it was dirty white, entirely lacking the orange rufous throat and upper breast of the adult. The eye ring, which is red in the adult, was dull yellow. When the young bird heard the low clicks of an adult it became excited, gaped, then flew or glided down into the foliage. An adult cuckoo guarded the nest area, sometimes with vigor. A Smooth-billed Ani (Crotophaga ani) flew into the bushes and was immediately attacked and driven away. At another time a Gray-capped Cuckoo (Coccyzus lansbergi) landed in the bushes, but it left in haste after only a few seconds. On the other hand, a pair of preening Scaled Doves (Scardafella squammata) was tolerated in the nest bush and a pair of Pied Water-Tyrants (Fluvicola pica) nesting 4 m away was unmolested. About half an hour after I found the juvenile, an adult cuckoo, which proved to be male, flew into the bush with a large moth in his bill. The moth was buff-colored with a thick furry body about 3 cm long. The cuckoo called and was answered, then a second adult cuckoo met it on a small horizontal branch. The pair perched side by side and engaged in an active tug-of-war, each alternately pulling the moth. The male jerked the moth free and then both birds flew to a higher perch. While the moth struggled, the male cuckoo mounted the female, who grasped the insect's body as they copulated. When they separated, the male was still holding the moth, but the female pulled it away from him and tried to eat it. The moth freed itself and dropped down into thick foliage where the female cuckoo followed

Birds of a Highland Clearing in Cundinamarca, Colombia

SEVERAL authors (Dugand 1947, Olivares 1969, Lehmann 1970) have noted effects on distribution of Colombian avifauna by land disturbance, particularly the ever-accelerating clearing of forest to make way for pasture and agriculture. This paper attempts to describe this process on a small ranch near the capital city of Bogota', which has been settled for more than a century and where, consequently, the altered ecology has more or less stabilized. The Finca Rancho Grande (40 36' N, 740 20' W), is situated 15 km west of Bogot'a in Santandercito, Cundinamarca, in the valley of the Bogot'a River, a tributary of the Magdalena, Colombia's principal river. The finca lies 8 km downriver from the famous Tequendama Falls, which mark one of the bounds of the altiplano. The finca's altitude, 1700 m, is thus considerably lower than that of the Sabana of Bogota (2600 m). Meyer de Schauensee (1964) defines the tropical zone as extending from 0 to 1385-1700 m, and the subtropical zone as going from the 1385-1700 m line to 2300-2600 m. This finca is at the altitude of overlap between the two zones. The avifauna consists mainly of tropical and subtropical species of the west slope of the Eastern AndesMagdalena Valley. So far 82 species of birds have been seen at the finca, 10 North American migrants and 72 residents in Colombia. The finca, roughly 500 m by 500 m (25 ha or 61.8 acres) in extent, lies on the north-facing slope of the east-west running valley. It is a stepsided valley, with approximately flat shelves alternating with grades as steep as 400, descending northward to the river, some 1.5 km away at a level of 1500 m. Almost the entire valley on both sides of the river, originally forested, has been converted into fincas for animal husbandry (cattle and horses) and orchards for coffee culture, with numerous small towns and weekend cottages built to take advantage of the pleasant climate (temperature 16.5?-24? C; 62?-75? F). Behind the finca, to the south, climbs the Cordillera Subia with peaks as high as 2800 m, and separating the valley of the Bogota' River from that of the Subia River. Much of this cordillera, parts of which were explored by the Chapman party in 1910-15 (Chapman 1917-), has, like the region around Santandercito, been cultivated for at least 100 years, but considerable stands of thick secondary humid forest (Cecropia, tree fern, tree-sized Melastomataceae Miconia) still remain around swamps. On hillsides too steep for human use (grades of at least 700)

Breeding Biology and Ecology of the Brown-Hooded Gull in Argentina

THE Laridae breed in a variety of habitats throughout the world. Of the 44 species of gulls (genus Larus), 19 nest exclusively on the ground and 19 others often or sometimes nest on flat ground. Many of the latter species also nest on cliffs and ledges. The adaptations of gulls for nesting on cliffs have been studied in some detail (cf. Cullen 1957; Emlen 1964; Hailman 1965, 1968; Smith 1966). Beer (1966) studied the breeding adaptations of the Black-billed Gull (Larus bulleri) for nesting on unstable river beds. I examined the behavioral and ecological adaptations in Franklin's Gull (L. pipixcan) for breeding in marshes (Burger 1972a). The Brown-hooded Gull (L. maculipennis) is the ecological counterpart of Franklin's Gull in South America (Weller 1967) where it usually nests in the pampa marshes of Argentina and Uruguay although it infrequently nests on dry ground (Wetmore 1926, Olrog 1959, Meyer de Schauensee 1970). Only very general descriptions of the breeding biology of the Brown-hooded Gull are available (MacDonagh 1944, Plotnick 1951, Moynihan 1962). I studied the behavior and ecology of nesting Brown-hooded Gulls in Argentina, placing emphasis on colony and nest site selection, coloniality, synchrony, and interspecific relationships.

Behavior of the Grassland Sparrow and Two Species of Seed-Finches

The behavior of many of the predominantly granivorous neotropical bird species conventionally grouped under the familial heading Fringillidae in field guides is poorly known. Documenting it may help promote a better understanding of the phylogeny and systematics of these birds and clarify the evolution and adaptive significance of their social systems. It thus seems worthwhile to report some brief observations I made on the territorial behavior and feeding habits of Grassland Sparrows (Myospiza humeralis), Large-billed Seed-Finches (Oryzoborus crassirostris), and Lesser Seed-Finches (0. angolensis) during a short field trip to Guyana in July 1971. The behavior of these species seems not to have been reported in any detail. These observations were an extension of a socioecological investigation of the finches of Trinidad and Tobago to be published elsewhere. I use finch and Fringillid as convenient terms for species listed under the family heading Fringillidae in Meyer de Schauensee (1970a). I spent 35 hours observing these species with the aid of 10 x 50 binoculars at four locations in Guyana.

Micrastur gilvicollis, a Valid Species Sympatric with M. ruficollis in Amazonia

For well over a hundred years the systematics of the smaller forms of the neotropical genus Micrastur, the forest falcons, has been a subject of controversy. General agreement has gradually resulted with respect to most of the taxa, but there is still confusion surrounding the forms gilvicollis and plumbeus and their relationship to M. ruficollis. It is generally believed that all the small forest falcons inhabiting Amazonia belong to a single form under the name gilvicollis. This form has been considered a distinct species by Hellmayr (1910:410, 1921:178), Pinto (1935: 96-99, 1947:322-328, 1964:91), Hellmayr and Conover (1949:255-258), Phelps and Phelps (1958:72), Meyer de Schauensee (1966:62), and Haverschmidt (1968:71). However, it has been treated as a geographic race of the widely distributed M. ruficollis by Sclater (1918:346), Hellmayr (1929:454), Peters (1931:278), Amadon (1964:19-22), Brown and Amadon (1968:750), and Meyer de Schauensee (1970:51). The present paper provides morphological and acoustical evidence to show that, contrary to generally prevailing concepts, there are actually two very similar but specifically distinct forms (sibling species) of small Micrastur which are sympatric, even largely syntopic, throughout Amazonia. One of these is relatively homogeneous morphologically throughout the area and should bear the name M. gilvicollis. The other is in fact a form of M. ruficollis and intergrades with neighboring forms in some of the peripheral areas of Amazonia.