bluebird

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of several North American songbirds of the genus Sialia, having blue plumage and usually a rust-colored breast in the male.

Century Dictionary and Cyclopedia

1. n. An American oscine passerine bird, of the genus Sialia, of which blue is the chief color. There are several species. The common or Wilson's bluebird, Sialia sialis, inhabits eastern North America. It is about 6½ inches long, blue above and dull-reddish and white below. In most parts of the United States it is a harbinger of spring, coming with a melodious song. It nests in holes, and lays plain pale-bluish eggs. The western or Mexican bluebird, S. mexicana, is very similar, but has a reddish patch on the back, and the throat blue. The arctic or Rocky Mountain bluebird, S. arctica, is a larger species, of a paler blue than the others, fading into white below, without any red.
2. n. Some other bird of a blue color: as, the fairy bluebird of Java, Irene turcosa.

Wiktionary

1. n. Any of various North American birds of the genus Sialia in the thrush family. Their plumage is blue or blue and red.

GNU Webster's 1913

1. n. (Zoöl.) A small song bird (Sialia sialis), very common in the United States, and, in the north, one of the earliest to arrive in spring. The male is blue, with the breast reddish. It is related to the European robin.

WordNet 3.0

1. n. fruit-eating mostly brilliant blue songbird of the East Indies
2. n. blue North American songbird