Hunting mode and success of African Peregrines Falco peregrinus minor: does nesting habitat quality affect foraging efficiency?

Peregrine Falcon Falco peregrinus hunting behaviour was studied at nest-sit es in three areas of South Africa over eight years. In Africa, resident Per egrines are mostly restricted to high cliffs, possibly because these struct ures provide optimal conditions for hunting. This hypothesis is examined in terms of the influence of nest-site quality, particularly cliff height, on foraging efficiency. Foraging mode Varied considerably between sites, and males foraged more actively than females but there was little variation in the design of hunts between sexes, seasons or study areas. Individually, Pe regrines spent 30-50% of the day on or near the nest cliff. On average, abo ut 0.5 hunts were recorded per hour of observation. Foraging mode was not c orrelated with cliff height or elevation above the surrounding terrain, but Peregrine pairs occupying higher cliffs achieved greater hunting success r ates. Most hunts were initiated from elevated perches on the nest cliff; an d perch hunts were more successful than strikes made from the air. Success was highest in strikes at doves and small passerines, and over habitats wit h moderate cover. The height difference between Peregrine and prey at the s tart of a hunt positively and significantly affected hunting success. Overa ll, Peregrines were relatively sedentary and made extensive use of the nest ing habitat as a foraging area. High nest cliffs contributed to foraging su ccess by providing perch-hunting falcons with an effective height advantage over their prey.