ACTIVITY BUDGET OF WHITE-FACED WHISTLING-DUCKS DURING WINTER AND SPRING IN NORTHERN KWAZULU-NATAL, SOUTH-AFRICA

Despite the fact that white-faced whistling-ducks (Dendrocygna viduata ) incur the added costs of flight-feather replacement on wintering are as, little is known about how they allocate their time and energy duri ng this period. We used focal sampling techniques to quantify diel act ivity patterns of nonbreeding white-faced whistling-ducks using semipe rmanent pans in northern KwaZulu-Natal, South Africa, during the winte r and spring of 1995. A large proportion of early winter (44% of diel activities), late winter (29%), and spring (50%) activities were attri buted to foraging. Increased foraging intensity during early winter an d spring (P < 0.05) corresponded with peak flight-feather replacement. Birds spent more time in comfort-related activities (sleep, loaf, pre en) during late winter (57%) than both early winter (35%) and spring ( 29%; P < 0.05). Time spent in locomotion (walk, swim, fly) decreased a s winter progressed and was lowest during spring, whereas alert behavi ors and aggression increased (P < 0.05). No courtship activities were observed. Activities of white-faced whistling-ducks were correlated mo re strongly with flock size and ambient temperature than several other climatic variables. Relative to waterfowl wintering in north-temperat e regions, the activity patterns of white-faced whistling-ducks were p robably influenced by either or both the nutrient costs of Feather rep lacement and a reduction in foraging opportunities during the flightle ss period, sis well as a low availability of cereal grains near winter ing areas. Fifty-three percent of foraging activities occurred nocturn ally, which further exemplifies the importance of considering nocturna l behaviors when assessing the activity patterns and energetics of wat erfowl.