Breeding density, habitat selection and reproductive rates of the Peregrine Falcon Falco peregrinus in Alava (northern Spain)

A population of 33-35 pairs of Peregrine Falcon in Alava (north Spain) was studied with the aim of assessing the habitat attributes that influence breeding density, habitat selection and breeding success. A strong relationship was found between density of the species in each UTM (Universal Transverse Mercator) square of 10 x 10 km and cliff availability. Habitat selection tons analysed by comparing 15 variables in 33 occupied and 25 unoccupied cliffs located at least 2 kill from the nearest Peregrine pair. Significant differences were found in five variables: cliff dominance, distance to the nearest Golden Eagle Aquila chrysaetos nesting cliff, steepness and altitude (all showing larger values in occupied cliffs), and cliff orientation, with occupied cliffs facing preferably south and east. Orientation, dominance and distance to the nearest Golden Eagle pair, and the distance to the nearest Eagle Owl Bubo bubo nesting cliff, were included in a discriminant analysis which classified 82.76% of the cliffs correctly. The productivity of the studied population was 1.44 young/territorial pair (n = 45), and no consistent relationship was found between breeding success and habitat variables.