Pigeons or doves are the bird family Columbidae. The common names pigeon and dove are often used interchangeably. In ornithology, dove tends to be used for smaller species and pigeon for larger ones. The feral domestic pigeon is often called the rock dove: it is common in many cities. There are more than 300 species in the family. They usually make nests of sticks, and their two white eggs are incubated by both the male and the female parent. Doves feed on seeds, fruit and plants.