Influence of intraspecific competition and habitat quality on diurnal activity budgets of breeding common goldeneyes

We examined how female common goldeneyes (Bucephala clangula) allocated tim e to various activities throughout the breeding cycle, and how time allocat ion was influenced by habitat quality (presence of fish competitors) and in traspecific competition. Before incubation and during incubation recesses, females spent 73% or more of observed time foraging, but brood defence beca me the dominant behaviour during brood-rearing (43%). Females preferentiall y used lakes with few or no fish at all stages of the breeding cycle. Femal es sharing lakes with other goldeneyes spent significantly more rime alert, in social interactions, and diving for food, and less time resting than fe males occupying lakes solely with their mate. Our results show that the amo unt of time female goldeneyes spend in various activities may be determined primarily by their metabolic requirements at each stage of breeding, but t hat habitat quality and intraspecific competition also influence how female s allocate their time.