Birds from Coahuila, Mexico

by Emil K. Urban

Dendroica townsendi (Townsend).—Townsend's Warbler is a spring and fall migrant in Coahuila. Miller (1955a:173) recorded D. townsendi on September 2 at Jardín del Sur in Chuperosa Canyon in the Sierra del Carmen. Burleigh and Lowery (1942:203) saw two individuals of Townsend's Warbler at Diamante Pass on April 14. Amadon and Phillips (1947:578) secured this species "in mesquite about twenty miles west of Saltillo on August 28." Dickerman saw Townsend's Warblers in the Sierra de la Madera on December 13, 1953; 20 mi. S Ocampo on April 4, 1954; and 13 mi. E San Antonio de las Alazanas on April 10, 1954.

Dendroica virens (Gmelin).—Dickerman saw one Black-throated Green Warbler 13 mi. E San Antonio de las Alazanas, 9350 feet, on April 10, 1954, in a white pine-Douglas fir-aspen association. This seems to be the first record of this species in Coahuila.

*Dendroica chrysoparia Sclater and Salvin.—Miller, Friedmann, Griscom, and Moore (1957:251) listed the Golden-cheeked Warbler from Hipólito on July 3.

Dendroica occidentalis (Townsend).—Specimen examined: one, ♂ 31592, from 13 mi. E San Antonio de las Alazanas, April 10, 1954.

The Hermit Warbler seems to be an uncommon spring and probably fall migrant in Coahuila. Miller, Friedmann, Griscom, and Moore (1957:252) reported D. occidentalis from the State. No. 31592, whose testes were not enlarged, was obtained in a pine-spruce-aspen association.

Geothlypis trichas brachidactylus (Swainson).—Miller, Friedmann, Griscom, and Moore (1957:261) listed this subspecies of the Yellowthroat as recorded from Coahuila.

Geothlypis trichas occidentalis Brewster.—Burleigh and Lowery (1942:204) found the Yellowthroat "only on the outskirts of Saltillo, where ... [this species] was not uncommon in the thickets, especially around a small stand of marsh grass bordering a pond." Three males that Burleigh and Lowery (loc. cit.) obtained were tentatively identified as G. t. occidentalis. Dickerman saw one male Yellowthroat at San Marcos (=20 mi. S Cuatro Ciénegas) on May 4, 1954.

Geothlypis nelsoni nelsoni Richmond.—Burleigh and Lowery (1942:204) noted the Hooded Yellowthroat "only on the open slopes above the summit of Diamante Pass at an elevation of about 8,000 feet" where they obtained an adult male.

*Icteria virens virens (Linnaeus).—Specimens examined: total 3: ♂ ♂ 32105-32106 from 12 mi. N, 12 mi. W Jiménez, 850 ft., June 19, 1952; and ♀ 32107 from 2 mi. W Jiménez, 850 ft., June 20, 1952.

From the paucity of records in the literature, I judge that the Yellow-breasted Chat is uncommon in Coahuila. Miller, Friedmann, Griscom, and Moore (1957:265) listed I. v. virens from Coahuila. Findley saw a Yellow-breasted Chat 2 mi. S and 3 mi. E San Juan de Sabinas on June 22, 1952. The sizes of the testes (7×4 mm.; 12 mm.) of Nos. 32105-32106, the size of the largest ovum (2 mm.) of No. 32107, and the dates (June 19, 20) on which these specimens were obtained indicate breeding by I. v. virens in northeastern Coahuila, an area southwest of the previously documented breeding range.