The influence of time of day and environmental conditions on the foraging behaviours of willie wagtails, Rhipidura leucophrys

Abstract

The insectivorous willie wagtail, Rhipidura leucophrys, exhibits a range of discrete, easily identified foraging behaviours that include wagging the tail and flashing the wing. We investigated whether wagtails adjust these, and other foraging behaviours, according to the time of day and environmental conditions. The rates of tail-wagging and wing-flashing were influenced by the time of day and light intensity. Tail-wagging was more frequent at the start and end of the day, while wing flashing was more frequent during the middle of the day. The rate of aerial prey captures was also highest during the middle of the day and lower in the early morning and late afternoon. These daily patterns of foraging behaviours correspond with the patterns of insect activity, which was greater in the middle of the day than in the early morning or late afternoon. The field data, together with experiments using a model wagtail tail, support the view that tail-wagging and wing-flashing are used to flush insect prey.