Birds from Coahuila, Mexico

by Emil K. Urban

Lanius ludovicianus gambeli Ridgway.—Miller, Friedmann, Griscom, and Moore (1957:214) recorded this subspecies from Hipólito on November 6.

*Vireo atricapilla Woodhouse.—Specimens examined: total 4: sex ? 32099-32100 from Sierra del Pino (=6 mi. N, 6 mi. W Acebuches), 5250 ft., July 3, 1952; and ♂ ♂ 31493-31494 from 16 mi. E, 18 mi. N Ocampo, May 8 and 9, 1954, enlarged testes.

The Black-capped Vireo seems to breed as far south as central Coahuila. Miller (1955a:171-172) reported this vireo as a summer resident in "the low catclaw-dominated scrub in the lower washes of Boquillas Canyon and its side valleys, at 4600 to 4800 feet" in the Sierra del Carmen. Dickerman found the Black-capped Vireo common on the dry scrub and oak hillside habitat 16 mi. E and 18 mi. N Ocampo.

Vireo griseus noveboracensis (Gmelin).—Ridgway (1904:184) recorded this subspecies of the White-eyed Vireo "west to Sabinas." Miller, Friedmann, Griscom, and Moore (1957:220) also recorded V. g. noveboracensis from Sabinas on May 25. I suspect that the specimen of V. g. noveboracensis from Sabinas that was taken on May 25 was a vagrant. V. g. noveboracensis may occur in Coahuila as a migrant or winter visitant; however, I do not believe that representatives of noveboracensis normally are resident in Coahuila.

*Vireo griseus micrus Nelson.—Specimen examined: one, ♂ 32101, from 2 mi. W Jiménez, 850 ft., June 20, 1952, measurements: wing, 58 mm.; tail, 43.5 mm.; culmen, 10 mm.; tarsus, 19 mm.

This subspecies of the White-eyed Vireo breeds in Coahuila. Miller, Friedmann, Griscom, and Moore (1957:221) recorded V. g. micrus from Sabinas on March 9 and May 14. The enlarged testes (5×3 mm.) of No. 32101 and the date (June 20) on which it was obtained suggest breeding in Coahuila.

Vireo huttoni stephensi Brewster.—This subspecies of Hutton's Vireo occurs in southeastern Coahuila as a migrant. Sutton and Burleigh (1939a:39) found V. h. stephensi fairly common at Diamante Pass on March 6. Ridgway (1904:198) recorded V. h. stephensi from Sierra Guadalupe in April.

*Vireo huttoni carolinae Brandt.—Specimens examined: total 3: ♂ 31588 from 20 mi. S Ocampo, 6500 ft., April 5, 1954, weight, 11 gms.; ♀ 32851 from 13 mi. E San Antonio de las Alazanas, July 6, 1955, weight, 14.2 gms.; and ♀ 32102 from 7 mi. S, 4 mi. E Bella Unión, 7200 ft., June 25, 1952.

To my knowledge, V. h. carolinae is the only resident subspecies of Hutton's Vireo in Coahuila. Burleigh and Lowery (1942:202) found V. h. carolinae in rather limited numbers in the woods bordering the summit of Diamante Pass. Miller (1955a:172) remarked that the subspecies carolinae was a common bird from 6500 feet to 8000 feet in the Sierra del Carmen. Miller (loc. cit.) took a female on April 12 that was nearly ready to lay and said that his specimens of carolinae from the Sierra del Carmen seem to be separate from V. h. stephensi and V. h. mexicanus. Our specimens showed no overlapping of characters with V. h. stephensi and V. h. mexicanus. The size of the largest ovum (2 mm.) of No. 32102 and the dates (June 25, and July 6) on which Nos. 32102 and 32851 were obtained suggest that V. h. carolinae is a resident in Coahuila.

*Vireo bellii medius Oberholser.—Specimen examined: one, ♂ 31495, from San Marcos, May 5, 1954, measurements: wing, 56 mm.; tail, 48 mm.; culmen, 9.5 mm.; tarsus, 18 mm.