'Cowbird' definitions:

Definition of 'cowbird'

(from WordNet)
noun
North American blackbird that follows cattle and lays eggs in other birds' nests

Definition of 'Cowbird'

From: GCIDE
  • Cowbird \Cow"bird`\ (-b[~e]rd`), n. (Zool.) The cow blackbird (Molothrus ater), an American starling. Like the European cuckoo, it builds no nest, but lays its eggs in the nests of other birds; -- so called because frequently associated with cattle. [1913 Webster]