Zebra finches (Taeniopygia guttata) are small (10g) songbirds native to the semi-arid regions of Australia and Timor. They are highly social, nesting colonially in groups of 20 to 1000, and are opportunistic breeders, beggining their reproductive cycles when rain falls. They are a common cage bird throughout the world, probably because they breed so readily and frequently; young birds reach sexual maturity 90 days after hatching.
Zebra finches are sexually dimorphic in their plumage and song behavior. Males sing and females do not. Males have a chestunt cheek patch, a chestnut stripe with white spots along the flank, and fine black and white striping on the neck above a broad black band across the chest. Females and have none of these markings, and their beaks are orange while the males' are red.
Although the sexual dimorphism in plumage and in song behavior is striking, the roles of the two sexes in raising young are relatively equal. Zebra finches form strong monogamous pair bonds (although some birds occasionally cheat on their mates). Males court females, females choose among their suitors, and the formation of a pair bond is marked by "clumping" (two birds perching so near to each other that they appear to merge in a ball of feathers) and mutual preening. The male builds the nest, the female lays a clutch of 3-8 eggs, and the two parents take turns incubating the eggs (for approximately 15 days) and feeding the young until they are independent. Young birds are uniformly gray and have black beaks; they begin to assume their adult plumage between 30 and 45 days after hatching.