BLACKBIRDS, ORIOLES: DWARF COWBIRD 663 
DWARF COWBIRD: Molothrus ater obscurus (Gmelin) 
Description. —Similar to the Sagebrush Cowbird but smaller. Male: Length 
(skins), 6-7.1 inches, wing 3.8-4.1. Female: Length (skins), 5.6-6.3 inches, wing 
3.4-3.7. 
Range. —Resident of the Southwestern United States and Mexico, from south¬ 
eastern California, southern Arizona, southwestern New Mexico, southern Texas, 
and southern Louisiana south to Vera Cruz, Oaxaca, Colima, and northeastern 
Lower California. 
State Records. —The small southern form of the Cowbird is about as common 
in Grant and Hidalgo Counties in southwestern New Mexico as its larger relative is 
elsewhere in the State. It leaves the State for the winter, but remains in the fall 
until November (Henry), and even once in 1854 until December 6, on the Gila River 
(specimen in U. S. National Museum). In the spring, the arrival of the first was 
noted at Carlisle April 26, 1890 (Barrell).—W. W. Cooke. 
Eggs. —Deposited in nests of other birds. 
General Habits. —In the Colorado Valley, Doctor Grinnell 
found flocks of about a hundred Dwarf Cowbirds staying about a town, 
“either roosting quietly in mesquites among the adobe ruins, or flying 
about in compact unanimously acting flocks, or feeding in company 
with other Blackbirds in cattle pens. In one case a bunch of fully 
40 were feeding close together on the ground in a calf corral, all with 
uptilted tails and quivering bodies, a mannerism peculiar to the 
species” (1914, p. 156). On the Colorado Desert, in summer, Doctor 
Grinnell found them “keeping in the near vicinity of water” (1915, 
p. 101). 
Their eggs have been reported by Herbert Friedmann as found 
in the nests of the Mexican Ground Dove, certain Orioles, the Gray¬ 
tailed Cardinal, Long-tailed Chat, Verdin, Black-throated Sparrow, 
Small White-eyed Vireo, and Curve-billed Thrasher (1925, pp. 548-549). 
To this list, Wilson C. Hanna, from an examination of nests victimized, 
adds the Traill Flycatcher, Willow Goldfinch, San Diego Song Sparrow, 
San Diego Towhee, Blue Grosbeak, Lazuli Bunting, two Vireos, a 
Yellow Warbler, the Golden Pileolated Warbler, and the Western 
and Plumbeous Gnatcatchers. 
Additional Literature.—Allen, G. M., Birds and Their Attributes, pis. 
facing pp. 204 and 206, pp. 235-236. 
TANAGERS: Family Thraupidae 
The four representatives of the tropical Tanager family, which 
come north into the United States for the summer, keep the characters 
that adapted them to their southern arboreal life and their habit of 
wandering through the forests feeding on flowers, fruits, and insects— 
brilliantly colored plumage with great sexual and seasonal differences, 
together with a long heavy conoidal bill with tip slightly notched and 
cutting edge of upper mandible more or less distinctly toothed or lobed 
