Something other than altruism is at work when offspring stay at the nest to help the parents. Helping one's parents has always been a virtue, but it is not a common trait among birds. In a number of species, however, young birds forgo nesting, at least initially, in order to help their parents. Nest helping, a form of cooperative breeding, is a behavior that is both complex and confusing. Why would young birds decide to stay and help their parents, rather than establish their own territory, form pairs, and raise their own young? After all, a main strategy of birds is to breed successfully and to leave viable offspring behind. Stated another way, birds seek to maximize the addition of their individual genes to the gene pool of the species. Nest helping sounds like altruism, whereby an individual puts the benefit of the species over that of himor herself. But altruistic behavior in birds is hard to explain. This requires a closer look.
展开▼
