Pigeons and doves are in the order Columbiformes and family Columbidae. There are five subfamilies within Columbidae, 42 genera and 308 species. They are easily recognizable and have a world-wide distribution (although they are not found in Antarctica). They live in almost all types of terrestrial habitats from desert to dense forest and large urban areas. Pigeons and doves are stocky birds that range from 15 to 75 cm long. Many of the seed-eating columbids are buff, grey and brown colors, while the fruit-eaters are often more brightly colored. Many have ornamentation and iridescent feathers on the neck, breast, back, wings and face. They range from solitary to extremely social; the now extinct passenger pigeons (Ectopistes migratorius) are reported to have occurred in flocks of up to two million birds that were so dense that they blocked out the sun.