The metabolic output of avian (Sturnus vulgaris, Calidris alpina) adipose tissue liver and skeletal muscle: implications for BMR/body mass relationships.

1. The oxygen uptake rate of avian adipose tissue, liver and skeletal muscle slices were measured. 2. The energy consumption of fat was less than one tenth that of liver and muscle. 3. Thus, interspecific allometric equations for the prediction of basal metabolic rate from body mass will not be accurate throughout the avian annual cycle unless changes in body composition are taken into account.