Postfledging dispersal in the endangered Lesser Kestrel Falco naumanni

Much is known about the breeding period of the threatened Lesser Kestrel, but little of the postfledging period. Here, I examine the postfledging dispersal of juvenile Lesser Kestrels, based on all ringing recoveries of Lesser Kestrels ringed as nestlings in Spain and recovered before September (migration) of the same year. Of 28 juveniles recovered, 19 (67.9%) dispersed and their median recovery distance was 210 km (range 41–578 km), with significantly northern directions. No difference was found in the dispersal distance between individuals ringed as nestlings in mid-north and mid-south Spain, nor was any correlation found between the recovery distance and ringing latitude. These findings for postfledging dispersal in juvenile Lesser Kestrels seem in accordance with predictions of a mental map hypothesis for homing, but they do not exclude food as a potential factor influencing such movements. However, these postfledging movements cannot be explained by the hypothesis of gathering information for identifying a future breeding site.