They are one of the most easily studied birds, feeding, nesting, and courting right under our noses. Spend a few minutes watching pigeons, and you'll likely witness the behavior leading to copulation. A male then struts around his mate, eventually standing up, spreading his tail, and bowing to coo at her. Other intimate pigeon behavior includes billing, often a prelude to mating, when the female sticks her bill down the male's throat and takes an offering of regurgitated food, and allo-preening, when pairs lightly preen each other's heads. Once paired, pigeons may mate for life.
Pigeons often nest high on protected ledges, under bridges, or in abandoned buildings.
When a nest site is selected, the male pigeon gathers twigs one by one, placing them next to the female, which sits on the nest and works them into a flimsy platform of twigs and grass or straw. Pigeons usually lay two white eggs that take about 18 days to hatch. Parents share incubation duties, with the male usually taking the morning to afternoon shift. The nest remains covered by one of the parents about 99 percent of the time. This protection from heat loss is especially important in cooler months.