Birds from Coahuila, Mexico

by Emil K. Urban

**Icterus wagleri wagleri Sclater.—Ridgway (1902:268) recorded Icterus wagleri from Saltillo. Hellmayr (1937:122-123) referred this record of Wagler's Oriole to I. w. wagleri.

*Icterus bullockii bullockii (Swainson).—This subspecies of Bullock's Oriole was listed as breeding by Miller, Friedmann, Griscom, and Moore (1957:282) at Monclova on May 12-19.

Euphagus cyanocephalus (Wagler).—Brewer's Blackbird is a common migrant in Coahuila. Miller (1955a:174) found a few as migrants in the Sierra del Carmen on April 27. Burleigh and Lowery (1942:205) remarked that "this blackbird was characteristically a bird of the towns and villages, the scattered flocks being invariably seen feeding in the streets and near the houses." They (loc. cit.) obtained three specimens at Diamante Valley on April 23 and remarked that the departure of these birds in spring was "extremely late."

*Cassidix mexicanus prosopidicola Lowery.—Specimens examined: total 3: ♀ 32893 from Parras, July 4, 1955, weight, 98.8 gms.; and ♂ ♂ 35418-35419 from Torreón, January 8, 1954.

This subspecies of Boat-tailed Grackle has been recorded from several localities in Coahuila. In southeastern Coahuila, Burleigh and Lowery (1942:205-206) noted this grackle "somewhat local in its distribution; it was found in cultivated fields about the towns and villages." These authors noted it at Saltillo, the Chorro del Agua, and "occasionally in the open valley south of Diamante Pass" and obtained specimens from "near Saltillo" and Diamante Valley. On August 18 Amadon and Phillips (1947:579) found C. m. prosopidicola at Las Delicias where "a fledged young was noticed begging for food...." Lowery (1938:4) recorded one specimen of C. m. prosopidicola from Monclova. Findley saw Boat-tailed Grackles 2 mi. W Jiménez on June 19, 1952, and 2 mi. S and 11 mi. E Nava on June 15, 1952.

The distribution and intergradation of Boat-tailed Grackles in Coahuila is presently poorly understood. C. m. prosopidicola from southeastern Coahuila may approach C. m. mexicanus, and there is probable intergradation of prosopidicola with monsoni in northwestern Coahuila (Phillips, 1950:78).

Molothrus ater ater (Boddaert).—Specimen examined: one, ♀ 31513, from 21 mi. S, 11 mi. E Australia, 4400 ft., May 3, 1954, measurements: wing, 102 mm.; tail, 64 mm.; tarsus, 26 mm.; culmen, 17 mm.

This subspecies of the Brown-headed Cowbird is uncommon in Coahuila. Amadon and Phillips (1947:579) took an adult male and a juvenile female M. a. ater at Las Delicias on August 15, both of which were considered early migrants. Dickerman obtained No. 31513 from a flock of eight cowbirds. Although the measurements of this specimen agree equally well with those of M. a. ater and M. a. artemisiae (Grinnell, 1909:275-281), the shape of the bill most closely resembles that of ater. Grinnell (1909:278) said that "ater has a tumid bill, broad and high at [the] base with [a] conspicuously arched culmen" whereas "artemisiae has a longer and relatively much slenderer bill, vertically shallow at [the] base and laterally compressed, with the culmen in its greater portion straight or even slightly depressed." The size of the ovary (8×4 mm.) of No. 31513 and the date (May 3) on which it was obtained suggest that this individual was a late migrant, still south of the breeding range of M. a. ater.

Molothrus ater artemisiae Grinnell.—This subspecies of the Brown-headed Cowbird is an uncommon migrant in Coahuila. Amadon and Phillips (1947:579) obtained, at Las Delicias, a juvenile male on August 15 and an adult male on August 17.

*Molothrus ater obscurus (Gmelin).—Specimens examined: total 18: ♂ ♂ 32112-32115 from 12 mi. N, 12 mi. W Jiménez, 850 ft., June 18 and 19, 1952; ♂ ♂ 32108-32111, ♂ 32116, and ♀ ♀ 32117-32120 from 2 mi. W Jiménez, 850 ft., June 20, 1952; ♀ 32491 from Las Margaritas, August 4, 1955; ♂ 31511 and ♀ 31510 from 16 mi. E, 18 mi. N Ocampo, May 8 and 7, 1952; and ♂ ♂ 35409-35410 (skeletons only) from 4 mi. N San Isidro, May 11, 1954.