Otherwise known as the rock dove
, scientific name Columba livia
, this bird has now nearly world-wide distribution, thanks to its association with human beings.
Originally native from Europe to North Africa and India, it was domesticated long ago and raised for food, trained for homing, racing and carrying messages, and has been used extensively in research. It now lives in cities all over the world. In places it has reverted to the wild, and nests on cliffs far from human habitation.
The rock dove was originally a seed-eater, and away from cities also eats waste grain, berries and acorns. It has been known to eat a few earthworms and some insects as well. In cities it may subsist primarily on popcorn, bread and other junk food provided by humans.
In the wild, the rock dove nests on sheltered cliff ledges. In cities, window ledges, rain gutters and similar sites provide an analog to the natural situation. The nest is built by the female with material provided by the male, of twigs, grass and similar materials. These birds probably mate for life. Each brood will be one or two eggs, but a pair may raise up to five broods per year.
The young will be fed "pigeon milk," a substance secreted by the crop, an enlarged pocket of the upper esophagus. During the nesting season the walls of the crop secrete a milky fluid that is rich in fat and protein. The young are fed pure pigeon milk for the first few days after hatching; then they begin to receive a mixture of the milk and some partially digested seeds or fruit. To be fed, the young bird will insert its bill into the corner of the parent's mouth, and the adult will regurgitate the milk or the mixture.
The birds do not migrate, and if they are displaced from a nesting area, they have a good homing ability to find it again. This ability was used in the past to make them carriers of messages.
The rock dove has few enemies in our cities. In some cities, peregrine falcons have begun to nest on high skyscraper ledges, and the falcons have found an abundant food source in the urban rock dove.
Having so few natural enemies, this flexible and adaptable bird very often makes a nuisance of itself in our cities, but it is impossible not to admire its persistence, and its success. While we have exterminated so many species of birds and animals, and we are rightly anxious about the extinction of so many life forms, this one makes its home in its numbers right under our noses, and thrives in the bargain.