Birds from Coahuila, Mexico

by Emil K. Urban

*Troglodytes brunneicollis cahooni Brewster.—Typical representatives of this subspecies of the Brown-throated Wren occur in northern Coahuila. In the Sierra del Carmen, Miller (1955a:170) found T. b. cahooni that in no way suggested compositus of the Sierra Madre Oriental. Burleigh and Lowery (1942:198) recorded a cahooni-like specimen from Diamante Pass in southern Coahuila.

**Troglodytes brunneicollis compositus Griscom.—Specimen examined: one, ♂ 32819, from 13 mi. E San Antonio de las Alazanas, July 6, 1955.

The subspecies cahooni and compositus of the Brown-throated Wren seem to intergrade in the southern part of the State. Although No. 32819 represents the subspecies compositus, the somewhat whitish abdomen and the fairly large spots of the lesser wing coverts suggest some relationship with cahooni. In addition to the present record, Miller, Friedmann, Griscom, and Moore (1957:163) recorded T. b. compositus from southern Coahuila at Sierra Guadalupe. The record of T. b. cahooni from Sierra Guadalupe (Ridgway, 1904:588) I suspect probably represents T. b. compositus or an intergrade between compositus and cahooni. The date (July 6) on which No. 32819 was obtained 13 mi. E San Antonio de las Alazanas suggests that this bird was resident there.

*Thryomanes bewickii eremophilus Oberholser.—Specimens examined: total 3: ♂ 32088 from 2 mi. W Jiménez, 850 ft., June 20, 1952; ♀ 31061 from 4 mi. W Hacienda La Mariposa, 2300 ft., March 24, 1952, weight, 10.8 gms.; and ♂ 31660 from the north foot of Sierra Guadalupe (=10 mi. S, 5 mi. W General Cepeda), 6500 ft., April 21, 1953, weight, 13 gms.

Bewick's Wren occurs commonly in Coahuila. Miller, Friedmann, Griscom, and Moore (1957:160) reported that, in Coahuila, T. b. eremophilus "intergrades in the eastern and southern sections with T. b. cryptus and T. b. murinus, respectively." The slightly darker coloration of No. 31660, suggesting a resemblance to T. b. murinus, is the only evidence of intergradation of T. b. murinus and eremophilus that I have found.

Miller (1955a:170) stated that T. b. eremophilus was "common in the piedmont area on yucca-dotted slopes and along the lower canyon walls in growth of piñon, yucca, and cactus" in the Sierra del Carmen, and reported breeding there. Burleigh and Lowery (1942:198) remarked that T. b. eremophilus "proved without question to be the most widely distributed and abundant wren" in the Saltillo region. The series that Burleigh and Lowery (loc. cit.) assembled "proved to be uniform and clearly referable to" T. b. eremophilus. Sutton and Burleigh (1939a:36) noted Thryomanes bewickii at San Pedro on January 29 and 30. Hardy saw a male T. b. eremophilus at Parras on July 4, 1955. Ridgway (1904:557) listed T. b. eremophilus from Saltillo in April and as breeding at Sabinas.

The sizes of the testes (8 mm.; 6×4 mm.) of Nos. 32088 and 31660, respectively, suggest breeding 2 mi. W Jiménez and Sierra Guadalupe.

**Thryomanes bewickii cryptus Oberholser.—Miller, Friedmann, Griscom, and Moore (1957:161) recorded T. b. cryptus from Saltillo.

*Thryothorus ludovicianus berlandieri Baird.—Specimens examined: total 3: ♂ 32086 from 12 mi. N, 12 mi. W Jiménez, 850 ft., June 19, 1952; sex ? 32087 from 2 mi. W Jiménez, June 20, 1952; and ♀ 31063 from 8 mi. N, 4 mi. W Múzquiz, 1800 ft., April 1, 1952, weight, 18.3 gms.

One subspecies of the Carolina Wren, berlandieri, occurs in Coahuila in the northeastern section of the State. Ridgway (1904:547) recorded T. l. berlandieri from Sabinas. The fact that No. 32086 was a juvenile suggests that the Carolina Wren breeds 12 mi. N and 12 mi. W Jiménez.