Breeding Success, Cliff Characteristics And Diet Of Peregrine Falcons At High Altitude In The Australian Capital Territory

Abstract

The nest-site characteristics, breeding density, fledging success and diet of the Peregrine Falcon Falco peregrinus in high-elevation forest in the Australian Capital Territory were studied at five active nests from 1991 to 1995. Breeding diet at five active nests at lower elevation near Canberra was also studied in 1991. At high-elevation sites the falcons' breeding diet consisted entirely of birds (37 identified species), mostly Rock Doves 'Columba livia', Galahs 'Cacatua roseicapilla', other parrots and Common Starlings 'Sturnus vulgaris', with some larger species such as Cockatoos Cacatua, magpies 'Gymnorhina', currawongs 'Strepera', and ravens 'Corvus'. At lower elevation the breeding diet also consisted entirely of birds (12 species), but mostly Silver Gulls 'Larus novaehollandiae', Galahs, other parrots, and Starlings, with no large, potentially dangerous prey. Prey at high-elevation sites differed from that in other Australian studies in the high proportion of large, heavy items. Falcons at high-elevation sites nested at lower density, on higher cliffs that were more sheltered from the weather and had nestlings of lower weight and lower fledging success, than those at lower-elevation sites. Falcons at forested high-elevation sites appear to face a shortage of suitable prey or capture opportunities, as well as harsher weather.