Effects of breeding and environment on body condition of maned ducks, Chenonetta jubata

Abstract

Body weights and fat levels of non-breeding maned ducks on the southern tablelands of New South Wales and in the Australian Capital Territory were high during spring and summer, and low during autumn and winter. During the non-breeding season, paired females were fatter than unpaired females but fat levels of paired and unpaired males did not differ. Protein levels of females did not vary significantly with season, but protein levels of males were lower in winter. Females undergoing rapid follicle development before laying were fatter than non-breeding birds in the same months. Before laying, females stored fat but not protein for egg production. They used 44% of their pre-laying fat while laying, and a further 47% of the body fat present at the beginning of incubation was used during it. Laying and incubating maned ducks, and ducks with young, were less fat than non-breeding birds in the same months. Body condition of maned ducks was related to food availability, whether breeding or not, to the stage of breeding, and in females to pair status.