Nestling provisioning rates of Peregrine Falcons in interior Alaska

We examined factors influencing nestling provisioning rates among Peregrine Falcons (Falco peregrinus) breeding along the Tanana River, Alaska, in 1995-97. Perching birds (Passeriformes) composed the majority (54.3%) of prey delivered to the nests; whereas, ducks and grebes composed the majority of prey biomass (60.8%). After accounting for stage of the nesting cycle, delivery rates of prey items and estimated prey mass increased with brood size. Prey mass was positively correlated with the length of time air adult was absent from the vicinity of the nest prior to prey delivery. Finally, although we found that delivery rates of prey per nestling decreased with increasing brood size, estimated mass delivered per nestling did not vary with brood size. Peregrine Falcons apparent]), maintained constant provisioning rates per nestling as brood size increased by increasing prey mass.