The avian diet of the Australian Hobby Falco longipennis breeding in an urban parkland in southern Victoria

Abstract

A total of 129 hours of observation was completed on a pair of Australian Hobbies Falco longipennis through two complete breeding seasons, from early courtship until at least a month after fledging. The pair raised three fledglings in the 1992–1993 breeding season and two fledglings in 1993–1994. Avian prey, prey transfer, prey partitioning, prey-delivery rates, potential impact on the local bird community and hunting behaviour are described. The avian diet was mainly small passerines and a few small parrots. The majority of prey by species was House Sparrows Passer domesticus and Common Starlings Sturnus vulgaris . At least 55% by number and 64% by biomass were introduced species. The mean mass of identified avian prey was 36 g. Bird species with mass of ≤25 g made up 71% by number and 49% by mass of the diet. In each breeding season, the prey-delivery rate was lowest during incubation (0.17 item/h in 1992–1993 and 0.14 item/h in 1993–1994, and 3.7 and 2.8 g/h, respectively) and increased during the nestling stages (0.65 and 1.12 items/h; 25.7 and 35.2 g/h, respectively). In 1992–1993, it continued to increase in the fledgling period (1.00 item/h and 32.5 g/h) but in 1993–1994 it decreased in the fledgling period (0.50 item/h and 15.4 g/h) after brood-reduction in the nest. Through each complete season, the prey-delivery rates were 0.57 item/h and 19.1 g/h (three fledglings 1992–1993) and 0.45 item/h and 12.7 g/h (two fledglings 1993–1994). Two species—Crested Shrike-tit Falcunculus frontatus and Common Greenfinch Chloris chloris —have not previously been recorded as prey of the Australian Hobby.