ENERGY-COST OF INCUBATION IN THE AMERICAN KESTREL

1. 1. Metabolic rates are presented for (1) two females and one male kestrel incubating eggs in the field. (2) the same individuals in the laboratory immediately following the incubation period, (3) non-breeding kestrels and (4) kestrel eggs for 10 days during their development. 2. 2. The results from one male and one female support the idea that incubation can be accomplished at the level of adult resting metabolism. 3. 3. Metabolism of the other female during incubation was greater than adult resting metabolism at air temperature below 15°C. Egg metabolism rises exponentially during mid-incubation period and reaches a plateau in the last 5-6 days at 21.2 mg CO2/egg per hr. 4. 4. In the last 5 days of the incubation period a clutch of five eggs contributes 19-25% of the total heat required for incubation. © 1979.