Birds from Coahuila, Mexico

by Emil K. Urban

Passerculus sandwichensis brunnescens (Butler).—Burleigh and Lowery (1942:208) recorded this subspecies of the Savannah Sparrow from Diamante Pass in April.

Ammodramus savannarum perpallidus (Coues).—Specimen examined: one, ♀ 31562, from 3 mi. N, 4 mi. E San Francisco (=25 mi. N Ocampo), 4850 ft., May 16, 1954, weight, 15 gms.

The Grasshopper Sparrow is an uncommon spring and possibly fall migrant in Coahuila. Miller, Friedmann, Griscom, and Moore (1957:367) recorded A. s. perpallidus from Sabinas on March 12. No. 31562, which was obtained in a yucca and acacia association, had little fat.

Ammodramus bairdii (Audubon).—Miller, Friedmann, Griscom, and Moore (1957:368) remarked that Baird's Sparrow is a rare winter visitant to the northern states of México and recorded A. bairdii from Saltillo on May 8.

Pooecetes gramineus confinis Baird.—The Vesper Sparrow seems to be an uncommon winter visitant in Coahuila. Miller (1955a:176) found P. g. confinis "on two occasions in the grass of the dry ciénega at the head of Corte Madera Canyon at 7500 feet" on April 9 and 14 in the Sierra del Carmen. In April, Burleigh and Lowery (1942:208) found P. g. confinis only in Diamante Valley where this sparrow "appeared to be quite uncommon." Sutton and Burleigh (1939a:45) took a male P. g. confinis at San Pedro on January 29.

*Chondestes grammacus strigatus Swainson.—Specimen examined: one, ♂ 32156, from 8 mi. N, 2 mi. W Piedras Negras, June 18, 1952.

The Lark Sparrow is not uncommon in Coahuila. Miller (1955a:176) saw one male, "apparently on a breeding territory, on April 27 in an open, rather barren desert flat adjoining the lower part of Boquillas wash at 4600 feet." He reported that Marsh took a young of the year, still largely in juvenile plumage, on September 6 in the Sierra del Carmen. Amadon and Phillips (1947:580) remarked that Lark Sparrows were common "about Las Delicias" after August 18. Findley saw Lark Sparrows 2 mi. W Jiménez on June 19, 1952, and 2 mi. S and 11 mi. E Nava on June 15, 1952. Dickerman saw Lark Sparrows at San Marcos on May 4, 1954. The pale and narrowly streaked upperparts of No. 32156 are typical for C. g. strigatus. The size of the testes (9×4 mm.) of No. 32156 and the date (June 18) on which it was obtained suggest breeding by the Lark Sparrow in northeastern Coahuila.

*Aimophila ruficeps tenuirostris Burleigh and Lowery.—This subspecies of the Rufous-crowned Sparrow is resident in the northern part of Coahuila. Miller (1955a:176) remarked that the species "ranged up to 7000 feet on open south-facing slopes within the oak belt" of the Sierra del Carmen. Specimens collected by him showed no approach to boucardi of southern México and seem to be closest to tenuirostris. Miller referred the specimen that Marsh and Stevenson (1938:287) took on August 22 in Chuperosa Canyon to tenuirostris rather than boucardi. Miller, Friedmann, Griscom, and Moore (1957:376) listed A. r. tenuirostris from 50 mi. S Monclova on November 8 and 10.

*Aimophila ruficeps boucardi (Sclater).—This subspecies of the Rufous-crowned Sparrow is common in southern Coahuila. Burleigh and Lowery (1942:208) indicated that A. r. boucardi was common throughout the mountainous areas and to some extent in the arroyos of the open desert country of southeastern Coahuila. Sutton and Burleigh (1939a:46) took a female A. r. boucardi "near Diamante Pass." Ridgway (1901:252) listed A. r. boucardi from Carneros. A. r. tenuirostris and boucardi seem to intergrade in central and even southern Coahuila. Miller, Friedmann, Griscom, and Moore (1957:376) recorded intermediate populations of the Rufous-crowned Sparrow from 12 mi. W Saltillo.

*Aimophila cassinii (Woodhouse).—Specimens examined: total 2: ♂ 32157 from 9 mi. S, 11 mi. E Sabinas, June 14, 1952; and ♂ 32158 from 18 mi. S, 14 mi. E Tanque Alvarez, 4000 ft., July 6, 1952.