Overview
Feral pigeons (Columba livia domestica or Columba livia forma urbana), also called city doves, city pigeons, or street pigeons, are descendants of domestic pigeons (Columba livia domestica) that have returned to the wild. The domestic pigeon was originally bred from the wild rock dove, which naturally inhabits sea-cliffs and mountains. Rock, domestic, and feral pigeons are all the same species and will readily interbreed. Feral pigeons find the ledges of buildings to be a substitute for sea cliffs, have become adapted to urban life, and are abundant in towns and cities throughout much of the world.
Owing to their capacity to create large amounts of excrement and be an occasional disease vector to humans combined with crop and property damage, pigeons are largely considered a nuisance and an invasive species, often disparagingly referred to as "rats with wings". Actions are taken in many municipalities to lower their numbers or completely eradicate them.
Physical characteristics
Feral pigeons are essentially the same size and shape as the original wild rock dove, but often display far greater variation in colour and pattern than their wild ancestors. The blue-barred pattern which the original wild rock dove displays is generally less common in more urban areas. Urban pigeons tend to have darker plumage than those in more rural areas.
From Wikipedia (CC BY-SA 4.0).