Effect of Wind on Avian Metabolic Rate with Particular Reference to Gambel's Quail

Abstract

The metabolic rate of Gambel's quail (Callipepla gambelii) increases linearly with increasing wind speed at both 10 and 20 C. These results are compared with data from the literature for seven other avian species. The square root of wind speed, though often used as the independent variable, does not provide the best description of metabolic rate in wind for most species and temperatures; however, presentation of all data in a common form does reveal patterns among and within species. The effect of convective heat loss on metabolic rate-that is, the slope of metabolism (in watts, W) on the square root of wind speed (m/s)-increases as mass increases. This slope also increases within a given species as ambient temperature ( ) decreases. These relationships are the result of relative changes in surface area, thermal conductance, and the temperature difference driving heat flux. The slope of the regression of metabolism on the square root of wind speed [b, in W/(m/s)^1/2] may be described as , where M is mass in grams and ΔT is the difference between the lower critical temperature and (in °C). This equation predicts the metabolic rate of a bird at any wind speed in temperatures below thermoneutrality.