Selective Prey Delivery to Incubating Females by Dominant Males, but not Helpers, in the Cooperatively Breeding Green Woodhoopoe

In cooperatively breeding bird species, one of the most conspicuous helping behaviours is the provisioning of food. Many studies have considered the feeding of nestlings, but far fewer have examined feeding of incubating females, and none have looked at the types of prey delivered at this stage. Here I show that green woodhoopoe ( Phoeniculus purpureus ) group members selectively feed incubating females with certain prey items: the diet delivered to incubating females contains a higher proportion of caterpillars, centipedes and cockroaches than that eaten by the provisioning adults themselves. The prey items selectively delivered are the largest in the diet and so might be provided in an effort to enhance the breeding female's condition, thus minimizing the time that she spends off the nest and so increasing hatching success. Intriguingly, it is only breeding males that show this adjustment in provisioning diet; helpers of both sexes simply provide the incubating female with the same proportions of different prey items that they eat when self-feeding. My results therefore offer the first evidence that members of cooperative groups may not all follow the same provisioning rules, and they also emphasize the need for studies to consider the incubation stage in just as much detail as the nestling phase if we are to understand fully the complexities of cooperative societies.