Pigeons and doves constitute the family Columbidae within the order Columbiformes, which include some 300 species of near passerine birds. In general parlance the terms "dove" and "pigeon" are used somewhat interchangeably. In ornithological practice, there is a tendency for "dove" to be used for smaller species and "pigeon" for larger ones, but this is in no way consistently applied, and historically the common names for these birds involve a great deal of variation between the term "dove" and "pigeon." This family occurs worldwide, but the greatest variety is in the Indomalaya and Australasia ecozones. The young doves and pigeons are called "squabs."

Pigeons and doves are stout-bodied birds with short necks and short slender bills with a fleshy cere. The species commonly referred to just as the "pigeon" is the feral Rock Pigeon, common in many cities.

Doves and pigeons build relatively flimsy nests from sticks and other debris, which may be placed in trees, on ledges, or on the ground, depending on species. They lay one or two eggs, and both parents care for the young, which leave the nest after 7 to 28 days. Doves feed on seeds, fruit and plants. Unlike most other birds (but see flamingo), the doves and pigeons produce "crop milk," which is secreted by a sloughing of fluid-filled cells from the lining of the crop. Both sexes produce this highly nutritious substance to feed to the young.

Morphology

Overall, the Columbidae tend to have short bills and legs, small heads on large compact bodies. The wings are large and have low wing loadings; pigeons have strong wing muscles (wing muscles comprise 31–44% of their body weight) and are amongst the strongest fliers of all birds. They are also highly maneuverable in flight.

The plumage of the family is variable. Granivorous species tend to have dull plumage, with a few exceptions, whereas the frugivorous species have brightly coloured plumage.Baptista, L. F.; Trail, P. W. & Horblit, H. M. (1997): Family Columbidae (Doves and Pigeons). In: del Hoyo, J.; Elliott, A. & Sargatal, J. (editors): Handbook of birds of the world, Volume 4: Sandgrouse to Cuckoos. Lynx Edicions, Barcelona. ISBN 84-87334-22-9 The Ptilinopus fruit-doves are some of the brightest coloured pigeons, with the three endemic species of Fiji and the Indian Ocean Alectroenas being amongst the brightest coloured. Pigeons and doves may be sexually monochromatic or dichromatic. In addition to bright colours pigeons may sport crests or other ornamentation.

Distribution and habitat

The family has adapted to most of the habitats available on the planet. The largest number of species are found in tropical forests and woodlands, where they may be arboreal, terrestrial or semi-terrestrial. Various species also inhabit savannas, grasslands, deserts, temperate woodlands and forests, mangrove forests, and even the barren sands and gravels of atolls.