Molothrus ater
Order Passeriformes
Family Icteridae
Subfamily Agelaiinae
♂ Adult male.— Head, neck, and upper breast rich brown (at a distance the bird seems entirely black); rest of plumage iridescent black.
♀ Adult female and Immature.— Entire plumage brownish-gray, unstreaked.
Nest, none, the eggs being laid in the nests of other birds.
Eggs, white, evenly speckled with brown
The Cowbird is a summer resident of New York and New England, but is rare in the hilly country of northern New England, and entirely absent from the unsettled forest regions. It arrives late in March or early in April. In late summer or early autumn the Cowbird is either absent or else occurs in large flocks, which occasionally linger through October. Cowbirds have several times been found in New York and New England in winter.
In spring flocks of two or three, or more, fly about in a restless fashion, and attract attention by a long, high whistle, followed by two shorter, lower notes. The bird’s flight is unsteady, and it looks distinctly smaller on the wing than the Red-winged Blackbird, with which it often associates. When the flock lights on trees, the males spread wings and tail, lift the latter, extend the neck, and follow these absurd gestures by a feeble squeak. Both sexes have a harsh chatter. They make no nest, and by laying in the nest of smaller birds, force them to bring up their young. The young Cowbird is brownish-gray, and generally larger, by the time it leaves the nest, than the foster-parent that is feeding it.
In summer Cowbirds are often seen following cattle about, walking on the ground. They can then be readily distinguished from the much larger Crow Blackbirds [Common Grackle] by the short, stout bill, by the reddish-brown head of the male, and by the grayish-brown females in the flock.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)