Birds from Coahuila, Mexico

by Emil K. Urban

Cassin's Sparrow seems to be common in Coahuila. The AOU Check-list Committee (1957:603) listed A. cassinii from 10 mi. E Saltillo. Miller, Friedmann, Griscom, and Moore (1957:378-379) recorded Cassin's Sparrow from Sabinas, on April 25; from 25 mi. SW Monclova, on November 20; from 12 mi. W Saltillo, on September 28; and from 10 mi. NE Saltillo, on July 3. These authors stated that Cassin's Sparrow was breeding 10 mi. NE Saltillo. The sizes of the testes (5×3 mm.; 7×5 mm.) of Nos. 32157-32158, respectively, and the dates (June 14, July 6) on which they were obtained are additional evidence of breeding by Cassin's Sparrow in Coahuila.

*Amphispiza bilineata bilineata (Cassin).—Specimens examined: total 5: ♂ 32159 and ♀ 32163 from 2 mi. W Jiménez, 850 ft., June 20, 1952; ♂ 32160 from 8 mi. N, 2 mi. W Piedras Negras, June 18, 1952; ♂ 32161 and sex ? 32162 from 5 mi. N, 19 mi. W Cuatro Ciénegas, 3250 ft., July 5, 1952.

The Black-throated Sparrow is common in Coahuila. Typical representatives of A. b. bilineata occur in eastern Coahuila. The center of the State is occupied by intergrades between A. b. bilineata, opuntia, and grisea. Miller, Friedmann, Griscom, and Moore (1957:381) reported A. b. bilineata from the "Saltillo area." Hellmayr (1938:539) recorded A. b. bilineata from Sabinas. The sizes (13, 14 mm.) of the white spot on the lateral tail feathers of Nos. 32163 and 32160, respectively, suggest A. b. bilineata. The short wing (61-64.5 mm.) and the lighter and browner color of the backs of Nos. 32163, 32160, and 32161 are suggestive of A. b. bilineata. Nevertheless, the size (8 mm.) of the white spot on the lateral tail feather of No. 32161 indicates intergradation with A. b. opuntia.

The sizes of the testes (6×4 mm.; 8 mm.) of Nos. 32160 and 32161, the size of the largest ovum (2 mm. in diameter) of No. 32163, and the presence of the juveniles from 2 mi. W Jiménez and 5 mi. N and 19 mi. W Cuatro Ciénegas indicate breeding by A. b. bilineata in Coahuila.

*Amphispiza bilineata opuntia Burleigh and Lowery.—Specimens examined: total 2: ♀ 31106 from 10 mi. S, 5 mi. E Boquillas, 1500 ft., March 3, 1952; weight, 12.3 gms.; and ♂ 31108 from 35 mi. S, 14 mi. E Boquillas, 2350 ft., March 12, 1952.

This subspecies of the Black-throated Sparrow occurs in northwestern Coahuila. Miller (1955a:176) stated that the Black-throated Sparrow was moderately common in the open desert scrub at the base of the Sierra del Carmen below 4800 feet. He said that the series of Black-throated Sparrows from the Sierra del Carmen "resembles most the race opuntia of western Texas ... but shows some intergradation toward grisea of southern Coahuila and toward A. b. bilineata of eastern Coahuila." He remarked also that the specimen from Jardín del Sur, which Marsh and Stevenson (1938:287) reported as A. b. grisea, was in extremely worn, dirty summer plumage and contributed nothing reliable to racial determination.

*Amphispiza bilineata grisea Nelson.—Specimen examined: one, ♂ 31665, from the north foot of Sierra Guadalupe (=10 mi. S, 5 mi. W General Cepeda), 6500 ft., April 25, 1953.

A. b. grisea is the subspecies of Black-throated Sparrow in southern Coahuila. Burleigh and Lowery (1942:208) saw this sparrow "frequently on the arid plateau around Saltillo" and obtained specimens there that were identified as A. b. grisea. Amadon and Phillips (1947:581) saw individuals on August 8 and 28 that were feeding "fledged young near Saltillo." The size of its wing (68.5 mm.), the slaty color of its back, and the size (8 mm.) of the white spot on its lateral tail feather suggest that No. 31665 is characteristic of A. b. grisea. The size of the testes (4.5×3 mm.) of No. 31665 indicates that A. b. grisea may breed in southern Coahuila.

*Junco phaeonotus palliatus Ridgway.—Specimens examined: total 3: ♂ 35402 (skeleton only) from 13 mi. E San Antonio de las Alazanas, 9345 ft., April 10, 1954; ♀ 33226 (skeleton only) from 13 mi. E San Antonio de las Alazanas, 9950 ft., July 6, 1955; and ♂ 31633 from Mesa de Tablas, 8600 ft., January 16, 1954, weight, 22 gms.

In Coahuila the Mexican Junco seems to be common. Miller (1955a:177) found it in the conifers of the upper Corte Madera drainage at 7500 feet and up to 8800 feet on Loomis Peak in the Sierra del Carmen. Marsh and Stevenson (1938:287) took an adult in Vivoras Canyon on August 14 in the Sierra del Carmen. Sutton and Burleigh (1939a:46) found small flocks at Diamante Pass in March. Burleigh and Lowery (1942:208-209) noted J. p. palliatus as a common bird of the mountain slopes above an elevation of about 7000 feet in southeastern Coahuila, and obtained specimens at Diamante Pass. Ridgway (1901:300) recorded J. p. phaeonotus from Sierra Encarnación. His record should be of J. p. palliatus as indicated by Miller, Friedmann, Griscom, and Moore (1957:386). Dickerman saw Mexican Juncos in the Sierra de la Madera on December 13, 1953.