Nestbox provisioning in a rural population of Eurasian Kestrels: breeding performance, nest predation and parasitism

The breeding biology of the Eurasian Kestrel Falco tinnunculus in nestboxes in farmland was studied to test for differences between artificial and nat ural sites. We report on the direct effect of nestbox provisioning on some life history traits and how nestbox use affects nest predation and parasiti sm. Five types of nest-sites were available: nestboxes on poles and frees ( artificial sites), stick nests on trees, stick nests on pylons and holes in buildings ('natural' sites). The Kestrel population increased from 23 pair s in 1993 (prior to nestbox installation) to 55 in 1998 as nestboxes were p rovided. In general, pairs breeding in trees started to lay later than thos e nesting in nestboxes on poles or in building holes, but this difference w as probably associated with habitat quality rather than nest type. Differen ces in clutch size were found between nest-sites in some years, and were as sociated with laying date and, probably, with variation in territory qualit y. Using only data from successful nests, pairs breeding in nestboxes produ ce more fledglings than those in building holes or pylons The frequency of nest predation was higher in natural sites than in nestboxes. The number of fledglings from pairs breeding in nestboxes was higher than from those bre eding in old stick nests in trees when all nests were considered. Nestbox p rovisioning had no effect on the occurrence of the ectoparasite Carnus hema pterus, but chicks from nestboxes showed higher intensity of infection. Our results suggest that nestbox provisioning increases reproductive success a nd the frequency of nest predation or intensify of parasite infestation in Kestrels.