BIRDS OF PENNSYLVANIA. 167 



GENUS MOLOTHRUS. SWAINSON. 

 495. Molothrus ater (BODD.). 



Cowbird; Cow Bunting; Cow Blackbird. 



DESCRIPTION. 



Bill, short, stout, about two-thirds as long as head ; tail nearly even or very slightly 

 rounded ; bill and feet black ; iris brown ; male with the head, neck and anterior 

 half of breast deep brown, with slight purplish gioss ; rest of body lustrous black, 

 with a violet purple gloss, next to the brown, of steel blue on the back, and of green 

 elsewhere. Female: Plain grayish-brown, lighter on the under parts. Young: Dull 

 dusky-brown above, feathers edged Avith grayish, lower parts light brownish gray 

 more or less streaked or spotted with darker markings. In the late summer and 

 early autumn the young male can often be distinguished by the conspicuous black 

 patches on the body. The female is smaller than the male. An adult male measures 

 about 8 inches in length and 13^ inches in extent. 



Hab. United States, from the Atlantic to the Pacific, north into southern British 

 America, south, in winter, into Mexico. 



This well known bird is a common summer resident in Pennsyl- 

 vania. It arrives here late in March or early in April, and migrates 

 southward about the middle of October. These polygamous birds, at 

 all times, are gregarious. In the autumn these birds, frequently in 

 company with the Crow Blackbirds and Robins, collect in large flocks 

 in thickets, where they roost during the night. When " coming in " to 

 these roosting places the flocks of Cowbirds do not scatter and alight 

 in the surrounding trees and bushes, as the Crow Blackbirds are 

 accustomed to do. but they fly in a compact body directly to the 

 thick bushy covert, where they remain, and unless disturbed are sel- 

 dom heard to utter their harsh, rattling chuckle. The Cowbird builds 

 no nest, nor does she attempt -to rear her young; when desirous of 

 laying, she quietly slips away from her companions, and finding a 

 nest deposits her egg, and flies off to join her comrades feeding in the 

 fields, or perhaps assembled in a treetop. Although the Cowbird 

 generally selects the nests of small birds, she never gains access to 

 the same by force, but pays her visit when the owners are absent. 

 Sometimes birds whose homes have been invaded by these feathered 

 parasites abandon their nests, mostly, however (particularly if one or 

 more of their own eggs have been deposited), they submit to the 

 imposition and rear the young Cowbirds. The Yellow Warbler, occa- 

 sionally, will build a new nest about that in which the unwelcome 

 -egg is deposited. I have twice found broken eggs of Cowbirds on the 

 ground near nests of the Yellow-breasted Chat, and on three occasions 

 have discovered the shattered remains of these eggs directly beneath 

 the pendant nests of Baltimore Orioles. It may be that these two 

 species, sometimes at least, toss out the alien eggs. While it is mostly 

 observed that the Cowbird lays in the nests of birds much smaller 



