There are about 45 species of crow worldwide known by a variety of names, including treepies, corbies, nutcrackers, bushpies, choughs, and the pica pica. Mating crows will often remain together for years and some until parted by death. Most of the offspring will leave the nest after a couple months never to return. Some, on the other hand, remain, assisting in co-operative breeding. Source: avesnoir