NONRANDOM DISPERSAL OF KIN - WHY DO EUROPEAN BEE-EATER (MEROPS-APIASTER) BROTHERS NEST CLOSE TOGETHER

Dispersal of close relatives within a breeding colony of European bee- eaters, Merops apiaster, was investigated by comparing the spatial sep aration of breeding relatives with that between the same individual an d a control individual hatched nearby in the same year. One-year-old m ales breed closer to their brothers, but not to their parents, than do controls. The main benefit of breeding in proximity to relatives appe ars to be enhanced helping behavior: potential helpers are more likely to help more quickly after nest failure when their own nest is close to that of the potential recipient of help. Breeding in proximity to r elatives also appears to carry a cost because nest failure is spatiall y aggregated: This implies that individuals breeding close to relative s arc less likely to have a relative available to help should their ow n breeding attempt fail. There was no evidence that the proximity of r elatives enhanced nest establishment, defense against predators, or in formation transfer.