Helpers at the nest

Helpers at the nest is a term used in behavioural ecology and evolutionary biology to describe a social structure in which juveniles and sexually mature adolescents of either one or both sexes remain in association with their parents and help them raise subsequent broods or litters, instead of dispersing and beginning to reproduce themselves.^[1] This phenomenon was first studied in birds where it occurs most frequently, but it is also known in animals from many different groups including mammals and insects. It is a simple form of co-operative breeding. The effects of helpers usually amount to a net benefit, however, benefits are not uniformly distributed by all helpers nor across all species that exhibit this behaviour.^[2] There are multiple proposed explanations for the behaviour, but its variability and broad taxonomic occurrences result in simultaneously plausible theories.^[3]

The term "helper" was coined by Alexander Skutch in 1935^[1] and defined more carefully in 1961 in the avian context as "a bird which assists in the nesting of an individual other than its mate, or feeds or otherwise attends a bird of whatever age which is neither its mate nor its dependent offspring." The term has been criticised as being anthropomorphic, but it remains in use.^[4] Other terms used especially in mammals, depending on the specific contexts, are non-maternal (care by other than the mother), alloparental (care by other than the parents), cooperative (care by non-breeding helpers) and communal (care by other breeding females) care.^[5]