Energy Costs of Activity and Daily Energy Expenditure in the Black Duck

Abstract

Heart rates of 3 wing-clipped black ducks (Anas rubripes) were successfully monitored for up to 11 days in the field. The energy costs of several activities, such as swimming, feeding, and preening, were calculated using regressions of metabolism on the heart rate previously determined in the laboratory for each duck. Total daily energy expenditure during midsummer using time-activity analyses of nonradioed black ducks was 1.5 to 2 times the resting metabolic rates measured in the laboratory. Preliminary data indicate that the energy costs for laying females may be as high as 3.4 times the resting rates. J. WILDL. MANAGE. 42(4):739-745 Investigations into the energy requirements of wild Anatidae have included feeding trails (Owen 1970, Penney and Bailey 1970, Sugden 1971, 1973, 1974, Sugden and Harris 1972, Miller 1974) and respiration calorimetry (Hartung 1967, Berger et al. 1970, Prange and Schmidt-Nielsen 1970, McEwan and Koelink 1973, Smith and Prince 1973, Wooley and Owen 1977). Recently, Dwyer (1975) estimated the energy requirements of free-living male gadwalls (Anas strepera) by extrapolation from time budget data. However, no direct measurements of metabolism under natural field conditions have been made. Owen (1969) and Wooley and Owen (1977) have discussed the relationship of metabolism to heart rate measured under laboratory conditions in blue-winged teal (Anas discors) and black ducks equipped with radio transmitters. We felt that this method offered promise for use with freeliving waterfowl to estimate the energy requirements for specific activities and to obtain daily energy budgets. The following report discusses the results of research on the energy requirements of semifree-living black ducks and the extrapolation of these data to free-living conditions. We thank C. J. Sniffen for his aid in laboratory work and statistical analysis, A. Fuller for his help in maintaining telemetry equipment, and the Maine Dept. of Inland Fisheries and Wildlife for supplying ducks. Special thanks are due to J. Sease, A. Lovewell, and M. Robson for aiding with field work.