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 degrees to 25
degrees 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
degrees-5 degrees C.

Keywords

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