Birds from Coahuila, Mexico

by Emil K. Urban

*Toxostoma longirostre sennetti (Ridgway).—Specimen examined: one, ♂ 32090, from 2 mi. S, 3 mi. E San Juan de Sabinas, June 22, 1952.

In Coahuila the Long-billed Thrasher seems to be uncommon. It has been recorded in Coahuila as far west as San Juan de Sabinas. Ridgway (1907:192) recorded T. l. sennetti from Sabinas, the only other record of the Long-billed Thrasher, to my knowledge, from the State. The large size of the testes (11×6 mm.) of No. 32090 and the date (June 22) on which it was obtained suggest that T. l. sennetti breeds 2 mi. S and 3 mi. E San Juan de Sabinas.

*Toxostoma curvirostre celsum Moore.—Specimens examined: total 2: ♀ 31071 from 7 mi. S, 2 mi. E Boquillas, March 1, 1952, wing, 111 mm., tail, 114 mm., weight, 97.2 gms.; and ♀ 31072 (skeleton only) from 10 mi. S, 5 mi. E Boquillas, 1500 ft., March 5, 1952.

This subspecies of the Curve-billed Thrasher occurs in northwestern Coahuila. Specimens of T. c. celsum and oberholseri from Coahuila are too few to show clearly the distribution and intergradation in Coahuila.

No. 31071 is referred to T. c. celsum because of large size; the spots on its upper abdomen, which are large and pronounced, suggest a relationship with T. c. oberholseri. Miller (1955a:170) remarked that T. c. celsum was a scarce resident of the desert scrub at the mouth of Boquillas Canyon of the Sierra del Carmen.

*Toxostoma curvirostre oberholseri Law.—Specimens examined: total 5: ♀ 35405 (skeleton only) from 4 mi. N San Isidro, May 11, 1954; ♀ 32091 from 5 mi. N, 19 mi. W Cuatro Ciénegas, 3250 ft., July 5, 1952; ♂ 32833 from Parras, July 4, 1955, weight, 76.5 gms.; ♀ 32092 from 7 mi. S, 4 mi. E Bella Unión, 7200 ft., June 25, 1952; and ♂ 31614 from 16 mi. W San Antonio de las Alazanas, 6500 ft., January 7, 1954, weight, 90 gms.

This subspecies of the Curve-billed Thrasher occurs in eastern and southern Coahuila. Amadon and Phillips (1947:578) took a Curve-billed Thrasher twenty miles west of Saltillo that had an enlarged ovary and a brood patch still somewhat evident on August 27. Burleigh and Lowery (1942:199) stated that T. c. oberholseri "was rather widely and commonly distributed, being noted from the area about the summit of Diamante Pass at 7,800 feet down to the desert country about Saltillo." Miller, Friedmann, Griscom, and Moore (1957:177) recorded T. c. oberholseri from Sabinas, from 8 mi. S Cuatro Ciénegas, and from El Diamante. Hellmayr (1934:298) also recorded T. c. oberholseri from Sabinas, as did Ridgway (1907:199) under the name T. c. curvirostre before the subspecies oberholseri was named. The female from 4 mi. N San Isidro had an egg in its oviduct. The immature male (32833), the large size of ovum (8 mm.) of No. 32092, and the presence of a brood patch on No. 32091 also are evidences of breeding by the Curve-billed Thrasher in Coahuila.

*Toxostoma dorsale dorsale Henry.—The Crissal Thrasher is uncommon in Coahuila. The subspecies dorsale occurs in northern Coahuila. Miller (1955a:170-171) found the subspecies dorsale, at about 4700 feet, only in the mesquite, desert willow, and walnut scrub along the wash of Boquillas Canyon of the Sierra del Carmen and remarked also that the bird nested there.

**Toxostoma dorsale dumosum Moore.—Specimen examined: one, sex ? 29559, from 8 mi. N La Ventura, 6000 ft., November 17, 1949, weight, 57.0 gms.

The subspecies dumosum of the Crissal Thrasher in Coahuila has been reported only from the southeastern section of the State. Burleigh and Lowery (1942:199-200) found T. d. dumosum "not uncommon in the lower foot-hills outside of Saltillo as well as on the summit of Diamante Pass." The specimen of T. d. dorsale from Diamante Pass reported by Sutton and Burleigh (1939a:37) is closer, according to Burleigh and Lowery (1942:199), to T. d. dumosum. No. 29559 is darker above and below than typical specimens of T. d. dorsale and represents T. d. dumosum.