Swallow
in ornithology, any one of the numerous passerine birds of the family Hirundinadæ. In the United States the best known species are the barn swallow; the cliff, eaves, or chim ney swallow; the white bellied or tree swallow, and the bank swallow. The species usually described by naturalists as the type of the family is Hirundo rustica, a well-known European visitor, whose arrival from Africa (usually about the middle of April) is eagerly looked for as a sign of approaching summer. Swallows us usually arrive in pairs -a male and a female-though several pairs often form a small flight. They return with unfailing regularity to their old haunts, and in May commence building their nests. The eggs, from four to six in number, are white, spotted with a purple-red. The food of the swallow consists entirely of winged insects. These are captured as the birds fly with open mouth, the bristles with which the gap is supplied and the viscid saliva assisting to retain the prey. Like owls, swallows reject the undigested portions of their food in small pellets or castings.
The male is about 8 inches long, beak black, forehead, chin, and throat, chestnut; head, neck, back, rump, and upper tail coverts steel-blue; tail very much forked; under surface buffy-white, legs and toes slender and black, claws black and sharp. In the female the tail feathers are not so long.