Foraging patterns and hunting success of the Eastern Barn Owl Tyto javanica delicatula in temperate Australia

Abstract

The foraging behaviour and success of the Eastern Barn Owl Tyto javanica delicatula were studied by JGM in an agricultural area of north-western Victoria in 1988–1990, by means of quantifying the owls’ nocturnal search and attack methods (n = 97 observations) and success rates (n = 55 observations) by habitat (open fields vs denser verge habitats) and season. Stationary perch-hunting formed 75%, low slow quartering 21% and sustained hovering 4% of observations. Terrestrial prey was captured by glide attacks from perches (75%) and hover-drop attacks from quartering flight (25%). Overall capture success rate of Barn Owls was 60%; glide attacks were successful on 64% of attempts, and hover-drop attacks on 40%. Overall, 65% of attacks were made in verge habitats and 35% in field habitats, although success was higher in field habitats (72%) than in verge habitats (54%). Perch-hunting comprised 85% of observations during autumn–winter and 64% during spring–summer, whereas quartering was recorded more frequently during spring–summer (32%) than during autumn– winter (11%). Verge habitats were more important during autumn–winter (87% of attacks) than spring–summer (39%). Perch-hunting was used throughout the night, but quartering and hovering were used after dusk and before dawn, more so in spring–summer than in autumn–winter.