The Significance of Clutch-Size in the Partridge (Perdix perdix)

Abstract

1. The first laying of the partridge {(Perdix} perdix) in England varies from 10 to 20 eggs, averaging 14.6. Late layings are smaller. 2. There are annual differences in the average size of first layings. 3. Average clutch-size is greater in northern and eastern Europe than in England. 4. Clutch-size is not limited by potential egg-production. 5. Hatching success is equal in clutches of between 8 and at least 20 eggs. 6. Clutch-size is considered to be selected through the food available for the brood and a method of proving this is suggested.