passerine species was 3 per cent, the North American element
39 per cent, and the Old World element 58 per cent whereas at Sonora,
Mexico, the South American element of breeding passerine species was 27
per cent, the North American element 52 per cent, and the Old World
element 21 per cent. The breeding avifauna of Coahuila is thus in line
with Mayr's analysis, resembling that of Sonora to a considerable
degree at the taxonomic level of Family.

ACCOUNTS OF SPECIES

**_Podiceps caspicus_ (Hablizl).--On March 31, 1952, Olmstead saw "many
Eared Grebes" on a pond 10 mi. E Hacienda La Mariposa. This is the
first record of the Eared Grebe in Coahuila.

[_Pelecanus erythrorhynchos_ Gmelin.--The White Pelican is uncommon, if
not rare; Friedmann, Griscom, and Moore (1950:21) list it.]

_Anhinga anhinga_ (Linnaeus).--On March 31, 1952, Olmstead noted an
Anhinga perched on a submerged fence post in a lake 10 mi. E Hacienda
La Mariposa. This is the first record of the Anhinga in Coahuila.

**_Ardea herodias_ Linnaeus.--Two subspecies of the Great Blue Heron,
_treganzai_ and _wardi_, have been recorded from Coahuila. Friedmann,
Griscom, and Moore (1950:27) listed _A. h. treganzai_ from the State;
presumably this subspecies occurs widely in low density. They (_loc.
cit._) remarked also that a record of _A. h. wardi_ from Coahuila
"cannot be allocated subspecifically."

Dickerman saw two Great Blue Herons in a marshy area at San Marcos (=20
mi. S Cuatro Cienegas) on May 4, 1954. Van Tyne and Sutton (1937:12)
noted the Great Blue Heron "near Boquillas [Texas], along the Rio
Grande, on May 10 and 15...."

**_Butorides virescens_ (Linnaeus).--Olmstead saw a Green Heron at
Boquillas, 700 feet, on March 10, 1952. Findley reported seeing Green
Herons 2 mi. W Jimenez, 850 feet, on June 19, 1952, and 2 mi. S and 3
mi. E San Juan de Sabinas on June 22, 1952.

**_Casmerodius albus egretta_ (Gmelin).--The Common Egret is an
uncommon migrant in Coahuila. Friedmann, Griscom, and Moore (1950:30)
recorded _C. a. egretta_ from the "extreme northern part" of Coahuila.
Van Tyne and Sutton (1937:12) saw the Common Egret "along the Rio
Grande on the Graham ranch just west of Boquillas," Texas, on May 16,
which might well be the locality to which Friedmann, Griscom, and Moore
referred. Olmstead saw a Common Egret at Don Martin on March 22, 1952.

**_Nycticorax nycticorax hoactli_ (Gmelin).--This subspecies of the
Black-crowned Night Heron was