Chapter 3

Published August 1, 1959

UNIVERSITY OF KANSAS Lawrence, Kansas

PRINTED IN THE STATE PRINTING PLANT TOPEKA, KANSAS 1959

Birds From Coahuila, Mexico

BY EMIL K. URBAN

INTRODUCTION

The following account is a summary of the present knowledge of the birds of Coahuila. Some 500 specimens from Coahuila in the Museum of Natural History at the University of Kansas are the basis for this report; these are supplemented by records of birds previously listed from the State.

In Coahuila, habitats vary from those characteristic near tree-line to those of the floors of the low deserts. Because of the variety of habitats, many kinds of birds are present in the State; at least 312 living named kinds of 249 species have been recorded. Possibly another 100 species will be reported after further studies have been made there. At least 154 of the species listed in this paper probably breed in Coahuila. The bird fauna in the State includes species characteristic of eastern North America and of western North America, species that range from the Atlantic to the Pacific Ocean, and species found only, or mostly, in Mexico.

I thank Professor E. Raymond Hall, Doctor Richard F. Johnston and Doctor Robert M. Mengel for their kind help, and Doctor Harrison B. Tordoff for first suggesting this study to me. Unless otherwise stated, the nomenclature in this paper is that of the A.O.U. Check-list Committee (1957). Catalogue numbers are those of the Museum of Natural History at the University of Kansas. In so far as known to me, all birds recorded in the literature from Coahuila are listed below. In a few instances the only support for occurrence is the ascription of a given kind to Coahuila (without mention of date, catalogue number, or precise locality) by Friedmann, Griscom, and Moore (1950), and/or the A.O.U. Check-list Committee (1957); when this is so the entire entry is inclosed within brackets. In the accounts beyond, an asterisk indicates that the kind breeds in Coahuila; two asterisks indicate probable breeding in the State.

LIST OF COLLECTORS

Persons who have obtained specimens of birds from Coahuila for the Museum of Natural History are as follows:

Albert A. Alcorn Joseph Raymond Alcorn Sydney Anderson Rollin Harold Baker James Sheldon Carey Peter Stanley Chrapliwy W. Kim Clark Robert William Dickerman John R. Esther James Smith Findley John Keever Greer John William Hardy Gerd H. Heinrich William McKee Lynn Jack M. Mohler Roger O. Olmstead Robert Lewis Packard Robert Julian Russell William J. Schaldach, Jr. Harrison Bruce Tordoff South Van Hoose, Jr. Olin Lawrence Webb

GAZETTEER OF LOCALITIES IN COAHUILA

The following place-names were used to record the localities of Coahuilan birds now specimens in the University of Kansas Museum of Natural History. Each place-name is followed by its location in degrees and minutes of latitude and longitude, respectively.

Acebuches.--28 deg.17', 102 deg.56'. Americanos.--27 deg.12', 103 deg.14'. Australia.--26 deg.18', 102 deg.18'. Bella Union.--25 deg.26', 100 deg.51'. Boquillas.--29 deg.11', 102 deg.55'. Castillon.--28 deg.21', 103 deg.33'. Cuatro Cienegas.--26 deg.58', 102 deg.04'. Diamante.--25 deg.22', 100 deg.54'. Don Martin.--27 deg.32', 100 deg.37'. Fortin.--28 deg.48', 101 deg.41'. General Cepeda.--25 deg.22', 101 deg.28'. Gomez Farias.--24 deg.58', 101 deg.02'. Hermanas.--27 deg.13', 101 deg.13'. Iglesias.--27 deg.34', 101 deg.20'. Jaco.--27 deg.50', 103 deg.55'. Jimenez.--29 deg.04', 100 deg.42'. La Babia.--28 deg.33', 102 deg.03'. La Gacha.--28 deg.09', 101 deg.31'. La Mariposa.--28 deg.12', 101 deg.49'. La Ventura.--24 deg.48', 100 deg.38'. Las Delicias.--26 deg.10', 102 deg.49'. Las Margaritas.--28 deg.42', 101 deg.14'. Mesa de Tablas.--25 deg.14', 100 deg.24'. Muzquiz.--27 deg.53', 101 deg.32'. Nava.--28 deg.25', 100 deg.46'. Ocampo.--27 deg.22', 102 deg.26'. Paila.--25 deg.38', 102 deg.09'. Parras.--25 deg.25', 102 deg.12'. Piedras Blanca.--29 deg.02', 102 deg.33'. Piedras Negras.--28 deg.43', 100 deg.32'. Sabinas.--27 deg.52', 101 deg.07'. Saltillo.--25 deg.26', 101 deg.00'. San Antonio de las Alazanas.--25 deg.16', 100 deg.37'. San Buenaventura.--27 deg.06', 101 deg.32'. San Francisco.--27 deg.37', 102 deg.37'. San Geronimo.--28 deg.30', 101 deg.48'. San Isidro.--27 deg.33', 102 deg.27'. San Juan de Sabinas.--27 deg.55', 101 deg.17'. San Lorenzo.--25 deg.28', 102 deg.12'. San Marcos.--26 deg.41', 102 deg.07'. San Miguel.--29 deg.14', 101 deg.22'. San Pedro de las Colonias (San Pedro).--25 deg.45', 102 deg.58'. Santa Teresa.--26 deg.27', 101 deg.21'. Tanque Alvarez.--27 deg.56', 102 deg.38'. Torreon.--25 deg.33', 103 deg.27'. Villa Acuna.--29 deg.19', 100 deg.56'.

For mountain ranges, the approximate center of the highland of each range is used as the point of reference.

Pico de Jimulco.--25 deg.08', 103 deg.16'. Sierra del Carmen.--29 deg.00', 102 deg.30'. Sierra de la Encantada.--28 deg.25', 102 deg.30'. Sierra de Guadalupe.--25 deg.13', 101 deg.32'. Sierra del Pino.--28 deg.15', 103 deg.03'. Sierra de la Madera.--27 deg.03', 102 deg.30'.

DISTRIBUTION OF THE KNOWN BREEDING BIRDS OF COAHUILA

Topography and Climate

Coahuila lies in the broad northern end of Mexico, immediately east of the center of the continental mass. The mountains of Coahuila, which are part of the Rocky Mountain-Sierra Madre Oriental Axis, extend in a north-south direction and divide the lower lands into two areas, a larger one, a part of the Central Plateau, to the westward and a smaller one, a part of the Gulf Coastal Plain, to the northeastward. Most of the mountains of Coahuila do not exceed 6000 feet in elevation. A few peaks such as in the Sierra del Carmen, Sierra del Pino, Sierra de la Madera, Sierra Encarnacion, and Sierra de Guadalupe, are more than 9000 feet high, and some more than 10,000 feet in elevation occur near the southeastern border of the State in the Sierra Madre Oriental. The Gulf Coastal Plain of northeastern Coahuila ranges from 700 feet to 1800 feet. The desert plains of the Mesa del Norte to the west of the Sierra Madre Oriental Axis are higher, more rugged, and more dissected than those of the Coastal Plain and are marked by scattered desert ranges, buttes, low hills, and knobs.

Most of Coahuila is arid. Rainfall is moderate on the Coastal Plain and is low west of the central mountains. Baker (1956:128-132) and Muller (1947:35-38) give good summary discussions of the topography and climate of Coahuila, and the reader is referred to these for further details.

Biotic Communities

Baker (1956:132) stated that "the biotic communities of Coahuila might be divided in accordance with the three physiographic areas of the State: the Gulf Coastal Plain, the mountains, and the desert plains of the Mesa del Norte." Goldman and Moore (1945:348-349) listed three biotic provinces in Coahuila: the Chihuahua-Zacatecas Biotic Province, in the western half of the State; the Tamaulipas Biotic Province, in the northeastern part of the State; and the Sierra Madre Oriental Biotic Province, in the southeastern part of the State. Merriam (1898) noted that definable portions of the Lower Sonoran Life-zone, the Upper Sonoran Life-zone, the Transition Life-zone, and the Canadian Life-zone can be distinguished in Coahuila. In my study of the distribution of the avifauna of Coahuila, I found that the three biotic provinces listed by Goldman and Moore (_op. cit._) as major headings and Merriam's life-zones as supplements are the most satisfactory divisions.

_The Tamaulipas Biotic Province._--This province consists of lowland plains and a few isolated ranges of low mountains. The average rainfall is 23 inches (Baker, 1956:130), considerably more than the 10 inches falling in the western part of the State. In the northeastern section of the State, the moderate amount of rain, mesic vegetation, and close proximity to the eastern migration pathway importantly influence the types of birds found.

In Coahuila, the Coastal Plain and the Rio Grande Plain lie in the path of the northernmost trade winds; they account for the more humid eastern slopes of the mountains of the northeastern part of the State (Muller, 1947:38). Nevertheless, the northeastern section of the State is semi-arid and can be placed in the Lower Sonoran Life-zone. The vegetation consists mainly of thorny shrubs and small trees with a liberal admixture of yuccas, agaves, and cacti, and closely resembles that of southern Texas, northern Nuevo Leon, and northern Tamaulipas (Goldman and Moore, 1945:354).

Migrant birds from the eastern flyway and less commonly migrants from western North America pass through northeastern Coahuila. The following breeding birds seem to be associated with this province: Harris' Hawk, Bobwhite (_C. v. texanus_), Scaled Quail (_C. s. castanogastris_), Yellow-billed Cuckoo, Groove-billed Ani, Green Kingfisher, Golden-fronted Woodpecker, Hairy Woodpecker (_D. v. intermedius_), Ladder-backed Woodpecker (_D. s. symplectus_), Vermilion Flycatcher (_P. r. mexicanus_), Cave Swallow, Gray-breasted Martin, Black-crested Titmouse (_P. a. atricristatus_), Carolina Wren, Long-billed Thrasher, Curve-billed Thrasher (_T. c. oberholseri_), Blue-gray Gnatcatcher (_P. c. caerulea_), Hutton's Vireo (_V. h. carolinae_), Bell's Vireo (_V. b. medius_), Yellow-throated Vireo, Red-eyed Vireo, Summer Tanager (_P. r. rubra_), Olive Sparrow, Cassin's Sparrow, and Black-throated Sparrow (_A. b. bilineata_).

_The Sierra Madre Oriental Biotic Province._--Southeastern Coahuila is in this province that includes mountains in southern Nuevo Leon, southwestern Tamaulipas, and eastern San Luis Potosi. Areas classifiable as Canadian, Transition, Upper Sonoran, and Lower Sonoran in life-zone are found in this province. This region of Coahuila receives the highest rainfall; this is evidenced by the luxuriant growth of boreal plants living in the higher places there (Baker, 1956:131). Spruce, pine, and aspen occur at higher elevations and oaks, thorny shrubs, and grasslands are present lower down.

Birds of central or southern Mexico reach the southern part of Coahuila; the Thick-billed Parrot, Hooded Yellowthroat, and Rufous-capped Atlapetes are examples. A boreal forest on the higher slopes of the mountains of southeastern Coahuila is suitable for certain northern birds such as Goshawks, Pine Siskins, and Brown Creepers. Some species of birds ordinarily associated with western North America are present in Coahuila only in its southeastern part; striking examples of disjunction in range thus occur. Probably sometime in the past these birds were distributed throughout most of Coahuila. When this area became arid, these species disappeared from all of Coahuila except from the high mountains in the southeastern part. For example, Steller's Jay and the Scrub Jay are absent in the Sierra del Carmen of northwestern Coahuila but do occur in southeastern Coahuila.

Migrants of the eastern flyway as well as migrants associated with western North America pass through this section of Coahuila. The following breeding birds are associated with this province: Goshawk, Band-tailed Pigeon, Thick-billed Parrot, Golden-fronted Woodpecker, Ladder-backed Woodpecker (_D. s. giraudi_), Pine Flycatcher, Buff-breasted Flycatcher, Vermilion Flycatcher (_P. r. mexicanus_), Steller's Jay, Scrub Jay, Mexican Chickadee, Black-crested Titmouse (_P. a. atricristatus_), Cactus Wren (_C. b. guttatus_), Robin, Blue-gray Gnatcatcher (_P. c. amoenissima_), Hutton's Vireo (_V. h. stephensi_), Bell's Vireo (_V. b. medius_), Hartlaub's Warbler, Summer Tanager (_P. r. cooperi_), Pine Siskin, Rufous-capped Atlaptes, and Black-throated Sparrow (_A. b. grisea_).

_The Chihuahua-Zacatecas Biotic Province._--This province in Coahuila covers the arid, interior, western desert area; it consists of rolling plains with mountains that rise islandlike above the general surface. Some of the mountains, such as in the Sierra del Carmen and the Sierra del Pino, are more than 9000 feet high. The major part of this biotic area lies within the Lower Sonoran Life-zone. Areas of the Transition and Canadian life-zones are present on some of the higher mountains; their discontinuity results in a discontinuous distribution of the conifer-dependent avifauna.

The large desert restricts the movement of birds considerably. Major results of this include isolation of certain populations and absence of others in the boreal islands. For example, Miller (1955a:157) noted that the "dispersal of conifer-belt birds to and from the Sierra del Carmen, although not as difficult as to well separated islands [such as off the coast of Baja California], is nevertheless a formidable matter to accomplish across the great deserts of Texas, Chihuahua, and Coahuila." Miller (_loc. cit._) noted also that the avifauna of the Sierra del Carmen, due to its insularity, is unbalanced and stated that "as a consequence of unbalance, species that are present show ecologic extension and unusual numerical relations." At least in this type of environment, an extension or expansion of the ecologic habits of the related types takes place when some species are absent.

This isolation influences local variation among some of the birds found in Coahuila. Niches elsewhere usually occupied by certain species, absent here, are occupied by other species. These other species thus enjoy an ecologic freedom and can expand their niches in the absence of related types of similar ecologic scope. For example, Miller (1955a:158-159) reported that Hairy Woodpeckers occurred only casually in the Sierra del Carmen and that the Ladder-backed Woodpecker has spread out and seems to occupy the niche or niches usually characteristic of the Hairy Woodpecker. Changes usually thought of as of subspecific character seem to be taking place between the Ladder-backed Woodpeckers of the Sierra del Carmen and of other areas, possibly because the Ladder-backed Woodpecker in the Sierra del Carmen is extending its ecologic sphere more than in areas where the Hairy Woodpecker exists. Restriction in dispersal due to geographic isolation has probably hindered gene flow, thus allowing rapid local adaptation, recognizable in variation at the infraspecific level. Miller (_loc. cit._) listed other birds that have expanded their ecologic scope; his work should be referred to for further details.

The following birds are associated with this province: Black Vulture, Scaled Quail (_C. s. pallida_), Turkey, Elf Owl, Green Kingfisher, Hairy Woodpecker (_D. v. icastus_), Ladder-backed Woodpecker (_D. s. cactophilus_), Wied's Crested Flycatcher, Buff-breasted Flycatcher, Vermilion Flycatcher (_P. r. flammeus_), Black-crested Titmouse (_P. a. dysleptus_), Cactus Wren (_C. b. couesi_), Curve-billed Thrasher (_T. c. celsum_), Blue-gray Gnatcatcher (_P. c. amoenissima_), Hutton's Vireo (_V. h. carolinae_), Summer Tanager (_P. r. cooperi_), and Black-throated Sparrow (_A. b. opuntia_). Several kinds of birds, such as the Band-tailed Pigeon, occur in the "pine islands" in this province rather than on the desert floor.

There remain several kinds of birds that are not especially associated with any one or two of the above-named provinces. These birds are widely distributed and vary geographically without corresponding to the Biotic Provinces. Examples of these species are: Black Phoebe (_S. n. semiatra_ in northern Coahuila; _S. n. nigricans_ in southern Coahuila), Violet-green Swallow (_T. t. lepida_ in northwestern Coahuila; _T. t. thalassina_ in southeastern Coahuila), Black-eared Bushtit (_P. m. lloydi_ in northern Coahuila; _P. m. iulus_ in southeastern Coahuila), White-breasted Nuthatch (_S. c. nelsoni_ in northern Coahuila; _S. c. mexicana_ in southern Coahuila), Brown-throated Wren (_T. b. cahooni_ in northern Coahuila; _T. b. compositus_ in southern Coahuila), Crissal Thrasher (_T. d. dorsale_ in northern Coahuila; _T. d. dumosum_ in southern Coahuila), and Rufous-crowned Sparrow (_A. r. tenuirostris_ in northern Coahuila; _A. r. boucardi_ in southern Coahuila).

Some representatives of the avifauna of the central and southern sections of the Central Plateau reach southwestern Coahuila. The subspecies _squamata_ of the Scaled Quail and _eurhyncha_ of the Blue Grosbeak are examples. Each in Coahuila seems to be at the northern limit of its range.

In summary, there are three associations of vegetation in Coahuila and each has characteristic birds. Gross climate and topography, through their influence on vegetation, are the prime factors in the distribution and kinds of birds in the State. Some birds of central and southern Mexico reach southeastern and southwestern Coahuila. Representatives of the Gulf Coastal Plain in Tamaulipas and Nuevo Leon as well as migrants of the eastern flyway occur in northeastern Coahuila. Most of the species that occur in Coahuila seem to be associated with western North America. The aridity of western Coahuila restricts, to a large extent, the diversity of the breeding populations of its avifauna. Xeric conditions surrounding some of the higher mountains are barriers to movement of some species.

ORIGIN OF BREEDING BIRDS OF COAHUILA

Probably beginning in the late Pliocene and ending in the Ice Age (Griscom, 1950:379) the refrigeration of climate in the Northern Hemisphere initiated a period of southward withdrawal of birds from the northern part of North America. Some members of the avifauna of Coahuila probably reached the State in this time. When the continental deserts were formed, or reformed, many tropical and subtropical Middle American species were forced to leave Coahuila. Species associated with arid conditions found their way there. Many representatives of the Old World element also seem to have found their way to the State during the refrigeration of climate in the Northern Hemisphere. The separation of North and South America in the greater part of the Tertiary (Mayr, 1946:9) that deterred mammals from intercontinental colonization seemingly did not hinder birds. Some South American species moved northward into Mexico, all the way north to Coahuila.

The avifauna of Coahuila today is a mixture of the several mentioned elements. Of the breeding populations, 43 per cent breed in the western rather than the eastern United States, 6 per cent breed in the eastern rather than the western United States, 30 per cent breed in both the eastern and western United States, 20 per cent are restricted to the Republic of Mexico, and the southern parts of Arizona, New Mexico, and Texas, and 1 per cent (Aztec Thrush and Rufous-capped Atlapetes) is endemic to the Republic of Mexico.

It is instructive to consider also the origin of avifaunal elements at the level of Family. According to Mayr (1946:11) most North American families and subfamilies clearly originated in the Old World, in South America, or from a North American element that developed in the partial isolation of North America in the Tertiary. Three other elements, the Panboreal, the Pan-American, and the Pantropical are represented by some North American families and subfamilies. Because of the obscurity of the place of origin of certain groups, an additional unanalyzed element must be recognized.

The Caprimulgidae and Picidae probably originated in North America (Mayr, 1946:26). Although the Psittacidae are Pantropical in distribution, indications are that they probably originated in the Old World (Mayr, 1946:17). The Phasianidae, Turdidae (_Myadestes-Hylocichla_ group), and Sylviidae (Polioptilinae) seem to have originated in the Old World (Mayr, 1946:27). However, Mayr considered these groups to have had a secondary center of proliferation in North America, and I thus consider these groups to have a North American origin. Mayr (1946:27) considered the Trochilidae, Tyrannidae, and Icteridae Pan-American in distribution; however, he suggested that they probably originated in South America, and I here treat them as South American in origin. No representatives of the Pan-American element that probably originated in North America have been recorded from Coahuila nor have members of the Panboreal element (Mayr, 1946:11) been recorded in the State. According to my analysis, representatives of families of birds known to breed in Coahuila and those that probably breed there thus seem to have been derived historically from the following sources:

Old World 24.7% North America 37.0% South America 24.0% Unanalyzed 14.3%

Mayr (1946:28-29) gave examples of analysis by geographic origin of the breeding species of several districts of North America. For instance, at Yakutat Bay in southeastern Alaska the South American element of breeding passerine species was 3 per cent, the North American element 39 per cent, and the Old World element 58 per cent whereas at Sonora, Mexico, the South American element of breeding passerine species was 27 per cent, the North American element 52 per cent, and the Old World element 21 per cent. The breeding avifauna of Coahuila is thus in line with Mayr's analysis, resembling that of Sonora to a considerable degree at the taxonomic level of Family.

ACCOUNTS OF SPECIES

**_Podiceps caspicus_ (Hablizl).--On March 31, 1952, Olmstead saw "many Eared Grebes" on a pond 10 mi. E Hacienda La Mariposa. This is the first record of the Eared Grebe in Coahuila.

[_Pelecanus erythrorhynchos_ Gmelin.--The White Pelican is uncommon, if not rare; Friedmann, Griscom, and Moore (1950:21) list it.]

_Anhinga anhinga_ (Linnaeus).--On March 31, 1952, Olmstead noted an Anhinga perched on a submerged fence post in a lake 10 mi. E Hacienda La Mariposa. This is the first record of the Anhinga in Coahuila.

**_Ardea herodias_ Linnaeus.--Two subspecies of the Great Blue Heron, _treganzai_ and _wardi_, have been recorded from Coahuila. Friedmann, Griscom, and Moore (1950:27) listed _A. h. treganzai_ from the State; presumably this subspecies occurs widely in low density. They (_loc. cit._) remarked also that a record of _A. h. wardi_ from Coahuila "cannot be allocated subspecifically."

Dickerman saw two Great Blue Herons in a marshy area at San Marcos (=20 mi. S Cuatro Cienegas) on May 4, 1954. Van Tyne and Sutton (1937:12) noted the Great Blue Heron "near Boquillas [Texas], along the Rio Grande, on May 10 and 15...."

**_Butorides virescens_ (Linnaeus).--Olmstead saw a Green Heron at Boquillas, 700 feet, on March 10, 1952. Findley reported seeing Green Herons 2 mi. W Jimenez, 850 feet, on June 19, 1952, and 2 mi. S and 3 mi. E San Juan de Sabinas on June 22, 1952.

**_Casmerodius albus egretta_ (Gmelin).--The Common Egret is an uncommon migrant in Coahuila. Friedmann, Griscom, and Moore (1950:30) recorded _C. a. egretta_ from the "extreme northern part" of Coahuila. Van Tyne and Sutton (1937:12) saw the Common Egret "along the Rio Grande on the Graham ranch just west of Boquillas," Texas, on May 16, which might well be the locality to which Friedmann, Griscom, and Moore referred. Olmstead saw a Common Egret at Don Martin on March 22, 1952.

**_Nycticorax nycticorax hoactli_ (Gmelin).--This subspecies of the Black-crowned Night Heron was listed from the "extreme north" section of Coahuila by Friedmann, Griscom, and Moore (1950:32). Van Tyne and Sutton (1937:14) saw three Black-crowned Night Herons along the Rio Grande about two miles west of Boquillas, Texas, on May 16. This record probably represents the locality to which Friedmann, Griscom, and Moore (_op. cit._) referred.

_Nyctanassa violacea violacea_ (Linnaeus).--A Yellow-crowned Night Heron in immediate post-juvenile plumage, No. 36413, was obtained on September 7, 1958, 16 km. south of Cuatro Cienegas, by W. L. Minckley. According to him the bird was accompanied by "several" other herons seemingly of the same species and condition of plumage. The species seems not to have been recorded previously from Coahuila [Eds.].

_Botaurus lentiginosus_ (Rackett).--Friedmann, Griscom, and Moore (1950:34) listed the American Bittern from the "extreme northern part" of Coahuila. Van Tyne and Sutton (1937:14) saw two representatives of this bittern "along the Rio Grande not far from Hot Springs," Texas, on May 15. I suspect that this is the locality to which Friedmann, Griscom, and Moore (_loc. cit._) referred.

[_Branta canadensis leucopareia_ (Brandt).--Friedmann, Griscom, and Moore (1950:38) listed _B. c. leucopareia_ from "northern Coahuila."]

**_Dendrocygna autumnalis_ (Linnaeus).--Evenden (1952:112) reported a Black-bellied Tree Duck standing beside a reservoir in southern Coahuila along the railroad between Saltillo, Coahuila, and Avalos, Zacatecas.

**_Anas platyrhynchos_ Linnaeus.--On March 30, 1952, Olmstead recorded a Mallard from 10 mi. E Hacienda La Mariposa, 2000 feet.

_Anas strepera_ Linnaeus.--_Specimen examined:_ one, [Male] 31016, from 10 mi. E Hacienda La Mariposa, 2000 ft., March 30, 1952.

The Gadwell is not an uncommon spring migrant; Olmstead saw it 10 mi. E Hacienda La Mariposa on March 30, 1952, and Baker observed it 8 mi. N and 4 mi. W Muzquiz on March 30, 1952. Friedmann, Griscom, and Moore (1950:42) recorded the Gadwell from Coahuila.

_Anas acuta_ Linnaeus.--Miller (1955a:161) took a Pintail on September 10 in the Sierra del Carmen.

_Anas carolinensis_ Gmelin.--The Green-winged Teal has been recorded from northern Coahuila. Van Tyne and Sutton (1937:15) recorded two mated pairs along the Rio Grande at Lajitas, Texas, on May 10. Miller (1955a:161) remarked that a male of the year was taken in the Sierra del Carmen on September 4.

_Anas discors discors_ Linnaeus.--_Specimens examined:_ total 2: sex ? 31646 and sex ? 31647 from .5 mi. S Las Margaritas, 2800 ft., September 28, 1953.

The Blue-winged Teal is a fairly common spring and fall migrant in Coahuila. Van Tyne and Sutton (1937:15) noted the Blue-winged Teal at several different localities along the Rio Grande: "on May 8, four males and several females resting on a mud bar along the Rio Grande near Hot Springs [Texas]; ... on May 7, three pairs in a flock, along the Rio Grande, Castalon [Texas]; ... and on May 20, three pairs, along the Rio Grande, San Vicente [Texas]." Miller (1955a:161) reported that Marsh took a male of the year in the Sierra del Carmen on September 10. Dickerman observed Blue-winged Teal 8 mi. E and 2 mi. S Americanos on May 18, 1954. Olmstead listed Blue-winged Teal from 10 mi. E Hacienda La Mariposa on March 30, 1952. Nos. 31646-31647, which are probably females, represent the subspecies _discors_ because the light edgings of their crowns are definitely present; the areas of their backs are brownish, not more intensively black, and their underparts are brownish, less blackish.

**_Anas cyanoptera septentrionalium_ Snyder and Lumsden.--Van Tyne and Sutton (1937:15) listed several localities along the Rio Grande in Brewster County, Texas, where Cinnamon Teal were seen. I suspect that Friedmann, Griscom, and Moore (1950:41) referred to those localities. Dickerman saw four pairs of Cinnamon Teal 14 mi. E and 16 mi. N Ocampo on May 9, 1954, and also saw Cinnamon Teal 8 mi. E and 2 mi. S Americanos on May 18, 1954.

_Mareca americana_ (Gmelin).--The American Widgeon is a fairly common spring migrant in Coahuila. Olmstead observed this duck 10 mi. E Hacienda La Mariposa on March 30, 1952. Dickerman saw five to seven American Widgeons 8 mi. E and 2 mi. S Americanos on May 18, 1954.

_Spatula clypeata_ (Linnaeus).--The Shoveler is a spring and probably fall migrant in Coahuila, and has been observed at several localities. Van Tyne and Sutton (1937:16) saw two pairs along the Rio Grande at Castalon, Texas, On May 7 and saw "a fair-sized flock along the Rio Grande on the Johnson ranch [in Texas] on May 13 and 14." Dickerman saw 12 pairs of Shovelers on two ponds 14 mi. E and 16 mi. N Ocampo on May 9, 1954, and 10 more 8 mi. E and 2 mi. S Americanos on May 18.

_Aythya affinis_ (Eyton).--Olmstead observed Lesser Scaup 10 mi. E Hacienda La Mariposa on March 30, 1952.

[_Bucephala albeola_ (Linnaeus).--Friedmann, Griscom, and Moore (1950:44) listed the Bufflehead from the State.]

*_Cathartes aura aura_ (Linnaeus).--_Specimen examined:_ one, [Male] 31017 (skeleton only), from 4 mi. W Hacienda La Mariposa, 2300 ft., March 26, 1952.

Miller (1955a:161) took a female Turkey Vulture, which was in breeding condition, in the Sierra del Carmen on April 17 and stated that "until more statistics are available on breeding birds of northern Coahuila, they must be considered _C. a. aura_...." Amadon and Phillips (1947:577) took a Turkey Vulture at Las Delicias which represented _C. a. aura_. Burleigh and Lowery (1942:188) stated that this species was not uncommon, and was noted each day soaring overhead both in the valleys and over the tops of the ridges of southeastern Coahuila.

Friedmann, Griscom, and Moore (1950:47) listed _C. a. teter_ from Coahuila. Miller (1955a:161) remarked that the subspecies _aura_ and _teter_ might intergrade in the Sierra del Carmen. At the present time it is possible to say only that _teter_ is present in Coahuila in migrant and wintering populations, but the extent to which _teter_ remains in northeastern Mexico is undetermined. However, all indications point to this area as being the region where _aura_ and _teter_ intergrade.

**_Coragyps atratus_ (Bechstein).--The Black Vulture is locally common throughout most of eastern Coahuila but is uncommon in the western part of the State. Sutton and Burleigh (1939a:25) noted the Black Vulture "regularly east of Saltillo in low country," but did not see Black Vultures at San Pedro or elsewhere in southwestern Coahuila. Burleigh and Lowery (1942:188) stated that "the Black Vulture apparently avoids to a large extent the higher altitudes, and only rarely was it observed at all, even about Saltillo." Olmstead saw Black Vultures 8 mi. N and 4