Columbiform

columbiform, (order Columbiformes), any member of the group of birds that contains the pigeons, doves, dodoes, and solitaires. The order Columbiformes is divided into the Raphidae, a family of extinct birds that embraces the dodo and the two species of solitaires, and the Columbidae, a family made up of extinct and living pigeons and doves. The names pigeon and dove are synonymous and imply no biological distinction.

The pigeon family is a natural and homogeneous assemblage of about 316 species of readily defined birds, unique in producing, for feeding their young, a nutritive secretion from the crop wall. Pigeon’s milk is similar in composition to mammalian milk and is also induced by the secretion of the hormone prolactin from the pituitary gland. Pigeons also are distinctive in their unusual manner of drinking, in which water is sucked in as a continuous draft, the process being assisted by muscular contractions of the esophagus, whereas other birds take a sip of water and then tip back the head to swallow.