Nest-site selection and breeding success in the Lesser KestrelFalco naumanni

Abstract

Nest site occupancy by Lesser Kestrels was studied in three colonies located in churches in southern Spain. Occupied nest-holes were located significantly higher than unused potential nest-holes. Precise nest dimensions, on the other hand, seemed to be of secondary importance. As breeding success was positively correlated with the height on the nest, we suggest that Lesser Kestrels selceted the highest positions to avoid predation and disturbance (by carnivores or humans). Additionally, 78% of all breeding attempts were in previously ooccupied nestholes and were more successful than attetmts in holes used only once during the 3-yearstudy. The fact that re-occupied, and hence preferred , nest registered earlier laying dates, suggests that a hierarchy might by established at the time of selcecting the nest site, This hierarchy would be determined by the different times of arrival of each individual at the ecolony after the winter.