The Kookaburra is the largest member of the knigfisher family. The little Australian lives in family groups in woodlands and open forests along the easern third of Australia and in the southwest corner of the continent.

The social system of kookaburras is unusual. They form permanent pairs, and the female lays two or three eggs in early spring in a hole in a tree trunk. The young hatch in 24 days, are fledged in 36, and are then fed by the parents for up to 13 weeks.

Instead of leaving the parents territory, the young remain with the parents for up to four years, and help defend the boundries and care for their parents new offspring. They spend aboyt one-third of the time required incubating their parents eggs and brooding the young, and they provide up to 60 percent of the nestlings food. This long juvenile period reduces breeding potential, but this does not pose a problem as kookaburras live up to 20 years. Their social system has survival advantage for all members of the group.