Pigeon, any of the hundreds of species of birds that make up the family Columbidae (Columbiformes). Smaller shapes are usually called doves, larger shapes are called pigeons. The exception is the white domestic dove, a symbol known as the "Peace Dove". Pigeons are found all over the world, except in the coldest regions and on the most remote islands. About 250 species are known; Two-thirds of them are found in tropical Southeast Asia, Australia and the western islands of the Pacific, but the family also has many members in Africa and South America, and several in temperate Eurasia and North America. Every member of the family absorbs fluid rather than swallows and swallows like other birds, and all pigeon parents feed on young "pigeon milk," a shredded crop that is stimulated by the hormone prolactin. The nest receives this "milk" by stuffing its berries into the parent's feed.