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Metabolic response to air temperature and wind in day-old mallards and a standard operative temperature scale

Bakken, G. S., Reynolds, P. S., Kenow, K. P., Korschgen, C. E., and Boysen, A. F., 1999, Metabolic response to air temperature and wind in day-old mallards and a standard operative temperature scale: Physiological and Biochemical Zoology, v. 72, no. 6, p. 656-665.

Abstract

Most duckling mortality occurs during the week following hatching and is often associated with cold, windy, wet weather and scattering of the brood. We estimated the thermoregulatory demands imposed by cold, windy weather on isolated 1-d-old mallard (Anas platyrhynchos) ducklings resting in cover. We measured O-2 consumption and evaporative water loss at air temperatures from 5 ° to 25 ° C and wind speeds of 0.1, 0.2, 0.5, and 1.0 mis. Metabolic heat production increased as wind increased or temperature decreased but was less sensitive to wind than that of either adult passerines or small mammals. Evaporative heat loss ranged from 5% to 17% of heat production. Evaporative heal loss and the ratio of evaporative heat loss to metabolic heat production was significantly lower in rest phase. These data were used to define a standard operative temperature (T-es) scale for night or heavy overcast conditions. An increase of wind speed from 0.1 to 1 mis decreased T-es by 3 °-5 ° C.

Keywords

Solar heat gain, thermal conductance, Auriparus flaviceps, cold stress, ducklings, thermoregulation survival, animals, ecology, birds