Cooperative and plural breeding by the precocial Vulturine Guineafowl

Abstract

Cooperative breeding in birds is thought to be more common in altricial species, with few described cases in precocial species. However, cooperative breeding may also be more difficult to detect in precocial species and could have been overlooked. We investigated whether precocial Vulturine Guineafowl Acryllium vulturinum breed cooperatively and, if so, how care is distributed among group members. We collected data from 51 uniquely marked individuals (27 males, 24 females), of which 13 females bred at least once over three different breeding seasons. We found that broods had close associates comprising both adults and subadults that exhibited four distinct cooperative breeding behaviours: babysitting, chick guarding, covering the chicks and calling the chicks to food. Further, we found that offspring care is significantly male-biased, that non-mother individuals provided most of the care that each brood received, that breeding females differed in how much help they received and that carers pay a foraging cost when providing care. In line with many other birds, we found that females received help from their sons. Our results confirm that Vulturine Guineafowl are cooperative and plural breeders and add to growing evidence that cooperative breeding may be more widespread among species with precocial young than previously thought, thereby providing a counterpoint to the altriciality-cooperative breeding hypothesis.