PARTITION OF FOOD-ENERGY FOR EXISTENCE IN THE KESTREL (FALCO-TINNUNCULUS) AND THE BARN OWL (TYTO-ALBA)

1. 1. The metabolisable energy values of a diet of day-old cockerels fed to kestrels and barn owls were 17.51 and 17.80 kJ/g dryweight respectively. 2. 2. In spite of a difference in the mode of digestion, both the kestrels and the barn owls retained about 72% of the gross energy of the diet for metabolism. 3. 3. Existence metabolism at 14°C was found to be 0.79 kJ/g bodyweight in kestrels and 0.72 kJ/g in barn owls. These exceed predictions from bodyweight for non-passerines at 30°C by about 28% and 16% respectively. © 1979.