Spatial segregation of home ranges between neighbouring colonies in a diurnal raptor

Abstract

Enhancement of information transfer has been proposed as a key driver of the evolution of coloniality. Transfer of information on location of food resources implies that individuals from the same colony share foraging areas and that each colony can be associated to a speciic foraging area. In colonial breeding vertebrates, colony-speciic foraging areas are often spatially segregated, mitigating intercolony intraspeciic competition. By means of simultaneous GPS tracking of lesser kestrels (Falco naumanni) from neighbouring colonies, we showed a clear segregation of space use between individuals from diferent colonies. Foraging birds from diferent neighbouring colonies had home ranges that were signiicantly more segregated in space than expected by chance. This was the case both between large and between small neighbouring colonies. To our knowledge, the lesser kestrel is the only terrestrial species where evidence of spatial segregation of home ranges between conspeciics from neighbouring colonies has been demonstrated. The observed spatial segregation pattern is consistent with the occurrence of public information transfer about foraging areas and with the avoidance of overexploited areas located between neighbouring colonies. Our indings support the idea that spatial segregation of exploited areas may be widespread among colonial avian taxa, irrespective of colony size.