In their native Australia, zebra finches typically breed in large colonies during the wet season, when food and water are abundant. These colonies can range in size from a few dozen to several thousand individuals. Within the colony, each pair of birds will defend their own nest and territory, but they may cooperate in other ways, such as sharing food and predator watch.
Zebra finches build relatively simple nests, typically made from grasses, twigs, and other plant material. Nests are usually built in trees or shrubs, but may also be found in other locations, such as under eaves or in old buildings. Zebra finches typically lay between 4 and 6 eggs per clutch, and both parents will participate in incubating the eggs and raising the young.
The chicks hatch after about two weeks and fledge from the nest about three weeks later. The young birds will stay with their parents and other members of the colony for some time before dispersing to find their own territories.
Zebra finches' colonial breeding behavior is thought to provide a number of benefits, including increased protection from predators, greater access to food, and increased opportunities for finding a mate.