Birds from Coahuila, Mexico

by Emil K. Urban

Nuttallornis borealis (Swainson).—Several records of the Olive-sided Flycatcher from Coahuila are present in the literature. Miller (1955a:167) reported it as a migrant in the desert at the base of the Sierra del Carmen on April 24. Miller, Friedmann, Griscom, and Moore (1957:82) reported this species from Ocampo on June 16. Amadon and Phillips (1947:578) obtained one at Las Delicias on August 16. Burleigh and Lowery (1942:194) collected two males "near the summit of Diamante Pass" on April 14.

*Pyrocephalus rubinus mexicanus Sclater.—Specimens examined: total 3: ♂ 32060 and ♀ 32061 from 12 mi. N, 12 mi. W Jiménez, 850 ft., June 19, 1952; and sex ? 32062 from 2 mi. W Jiménez, 850 ft., June 20, 1952.

The Vermilion Flycatcher is common in Coahuila. Except in the northwestern part of the State, the subspecies mexicanus is present throughout Coahuila. The size of No. 32060 (wing, 80 mm.; tail, 62 mm.) suggests that the specimen is an intergrade between P. r. flammeus and mexicanus. P. r. flammeus and mexicanus seem to intergrade in northern Coahuila.

Burleigh and Lowery (1942:195) found mexicanus to be "quite plentiful on the plains surrounding Saltillo." Sutton and Burleigh (1939a:33) noted the Vermilion Flycatcher "near San Pedro." Cory and Hellmayr (1927:92) listed P. r. mexicanus from Sabinas. The size of the testes (6×4 mm. long) of No. 32060 and the dates (June 19 and 20) on which our specimens were collected indicate breeding.

Pyrocephalus rubinus flammeus van Rossem.—This subspecies of Vermilion Flycatcher occupies the northwestern section of Coahuila. Marsh and Stevenson (1938:287) took a specimen of P. r. flammeus "near Santo Domingo, east of the Del Carmens...." Miller (1955a:167) re-examined this specimen and stated that "its affinity with the northwest race of the species seems correct in terms of the characters outlined by van Rossem (1934:353)."

Eremophila alpestris enthymia (Oberholser).—Miller, Friedmann, Griscom, and Moore (1957:105) recorded this subspecies of Horned Lark wintering 4 mi. S Hipólito (November 2 to February 24). They reported also that E. a. enthymia breeds in Coahuila (4 mi. S Hipólito ?).

*Eremophila alpestris diaphora (Oberholser).—Specimens examined: total 9: ♂ ♂ 32073-32078 and ♀ 32079 from 7 mi. S, 4 mi. E Bella Unión, 7200 ft., June 25, 1952; and ♂ ♂ 31605-31606 from 14 mi. W San Antonio de las Alazanas, 6500 ft., January 9, 1954.

Burleigh and Lowery (1942:195) wrote that this subspecies of Horned Lark was uncommon "about Saltillo," but "fairly common" in Diamante Valley, at about 7000 feet. Oberholser (1902:863) recorded the subspecies aphrasta from La Ventura. Ridgway (1907:326) listed Otocoris alpestris aphrasta Oberholser from Saltillo and La Ventura. However, Miller, Friedmann, Griscom, and Moore (1957:105) indicated that E. a. diaphora rather than aphrasta was recorded from Saltillo and La Ventura. Sutton and Burleigh (1939a:35) remarked that "specimens collected near Ramos Arizpe [in southeastern Coahuila]" proved to be E. a. aphrasta. However, this record might be questioned, as Miller, Friedmann, Griscom, and Moore (op. cit.) indicated, because diaphora, rather than aphrasta, seems to occupy the southeastern sector of Coahuila. Possibly typical representatives of aphrasta and/or intergrades between aphrasta and diaphora are present in western Coahuila; however, no records of E. a. aphrasta exist from western Coahuila.

The sizes of Nos. 32073-32077 and 31605-31606 (wing, 98.0-101.5 mm., averaging 99.7 mm.), the bright yellow throat, and the vinaceous color of the hindneck characterize clearly the subspecies diaphora. The sizes of the testes (9×6 mm.; 8×5 mm.; 10×6 mm.; 8×4 mm.; 11×6 mm.) of Nos. 32073-32077, the size of the largest ovum (6.5 mm.) of No. 32079, and the juvenile (32078) are evidence of breeding of E. a. diaphora in Coahuila.

*Tachycineta thalassina thalassina (Swainson).—Specimens examined: total 3: ♂ 31471, ♂ 31473, and ♀ 31472 from Sierra del Pino (=5 mi. S, 3 mi. W Acebuches), May 15, 1954, measurements: wings, 125, 118, 108 mm.; tails, 56, 54, 46 mm.