Birds from Coahuila, Mexico

by Emil K. Urban

The Rufous-capped Atlapetes occurs uncommonly in southeastern Coahuila. The male and female A. p. dilutus from 13 mi. E San Antonio de las Alazanas represent the first records of occurrence of this subspecies in the State. The smaller size, grayer upper parts, and pale yellow color of the underparts of Nos. 32942-32943 characterize the subspecies dilutus. The size of the testes (7×6 mm.) of No. 32942 and the date (July 6) on which both specimens were collected indicate breeding by this species in Coahuila.

*Arremonops rufivirgata rufivirgata (Lawrence).—Specimens examined: total 2: ♂ 32152 and ♀ 32153 from 2 mi. S, 3 mi. E San Juan de Sabinas, June 22 and 23, 1952.

The Olive Sparrow is uncommon in Coahuila. Miller, Friedmann, Griscom, and Moore (1957:349) listed A. r. rufivirgata from Sabinas on February 10. Sabinas and southeast of San Juan de Sabinas seem to be the only localities in Coahuila where the Olive Sparrow has been collected and also are at the westernmost extremity of range of this species. The size of the testes (9×7 mm.) of No. 32152 and the dates of collection indicate breeding by the Olive Sparrow in Coahuila.

Chlorura chlorura (Audubon).—Specimen examined: one, ♂ 30238, from 1 mi. N San Lorenzo, 4200 ft., February 5, 1951.

The Green-tailed Towhee is a common migrant and winter visitant in Coahuila; the species has been found at several localities. Miller (1955a:175) noted several migrants "each day in the last week of April ... at the mouth of Boquillas Canyon" of the Sierra del Carmen. Burleigh and Lowery (1942:207) noted the species "in an arroyo in the open desert country about twenty miles west of Saltillo on April 22." Miller, Friedmann, Griscom, and Moore (1957:351) listed the Green-tailed Towhee from 12 mi. W Saltillo on September 28 and from Sabinas.

*Piplio erythrophthalmus gaigei Van Tyne and Sutton.—Specimens examined: total 3: ♀ 31102 from Fortín (=33 mi. N, 8 mi. W San Gerónimo), 3300 ft., March 28, 1952, weight, 38.8 gms.; ♂ 35412 (skeleton only) from Sierra del Pino (=5 mi. W, 3 mi. S Acebuches), 6200 ft., May 15, 1954, testes enlarged, weight, 34 gms.; and ♂ 31593 from 17 mi. S Ocampo, 5300 ft., April 7, 1954, weight, 38 gms.

The Rufous-sided Towhee is locally common in Coahuila; P. e. gaigei is present in northern Coahuila. Miller (1955a:175) remarked that "between 6800 and 7500 feet these towhees were sparsely distributed in areas of scattered low ceanothus and hawthorne, chiefly in canyon bottoms, but also on slopes where ceanothus was intermingled with downed timber and young pines." He (loc. cit.) indicated that the adult obtained by Marsh from Vivoras Canyon on August 25 was P. e. gaigei rather than P. maculatus montanus (see also Sibley, 1950:127). Dickerman saw Rufous-sided Towhees in the Sierra de la Madera on December 13, 1953. I have referred Nos. 31102 and 31593 to gaigei although both are close to orientalis. The size of the testes (14×8 mm.) of No. 31593 suggests breeding.

*Piplio erythrophthalmus orientalis Sibley.—Specimens examined: total 3: ♂ 32154 from 7 mi. S, 4 mi. E Bella Unión, 7200 ft., June 25, 1952; ♂ 33223 (skeleton only) from 13 mi. E San Antonio de las Alazanas, 9950 ft., July 6, 1955; and ♂ 31630 from Mesa de Tablas, 8600 ft., January 15, 1954, weight, 46 gms.

This subspecies of the Rufous-sided Towhee occurs in southeastern Coahuila. Burleigh and Lowery (1942:207) stated that it "was limited in its distribution to the mountain sides ... [and was] noted in the arroyos at the base of the mountains and from there up to about 8,000 feet." These authors identified their specimens from Diamante Pass and from Saltillo as Pipilo maculatus gaigei. Sibley (1950:129) reidentified them, as well as a series from Sierra de Guadalupe, as P. e. orientalis. The size of the testes (12×7 mm.) of No. 32154 as well as the date (June 25) on which it was obtained suggests breeding by the Rufous-sided Towhee in southeastern Coahuila.

*Pipilo fuscus potosinus Ridgway.—Specimens examined: total 3: ♂ 32155 from 7 mi. S, 4 mi. E Bella Unión, 7200 ft., June 25, 1952; ♂ 31676 from the west foot of Pico de Jimulco, 5000 ft., April 5, 1953, weight, 45 gms.; and sex ? 29560 from 7 mi. S, 1 mi. E Gómez Farías, 6500 ft., November 19, 1949, weight, 46.5 gms.