Getting kids to help their younger brothers and sisters may be more difficult in some human families than in some bird families. The parents in some bird families get help from the youngsters of a previous brood in raising the youngsters in the newest brood.
This interesting behavior, called "cooperative breeding," is found among bluebirds. When a pair of bluebirds is successful in raising a brood of youngsters early in the breeding season, they will usually attempt a second nesting. The youngsters of the first nesting help by gathering and serving food to their younger siblings. This efficient use of birdpower increases the survival rate of the new brood, because they are fed more often, and there are extra eyes watching for predators.
Crows are also well-known for their cooperative breeding. But the difference between crows and bluebirds is that the young crows of the previous year’s nesting are the helpful siblings. During their first year, and sometimes the second year, immature crows often help their parents build nests, watch for predators, and gather food for the new brood.
Recent studies of the Florida Scrub-jay have shown a similar behavior. The young of the previous year will often help their parents raise the following year’s young. This behavior among Florida Scrub-jays may be due to the scarcity of suitable nesting habitat, as the Florida Scrub-jay population is confined to a small area of scrubby brush in central Florida, where suitable nesting habitat is limited.
-- George H. Harrison