A RANDOM FEMALE SETTLEMENT MODEL CAN EXPLAIN POLYGYNY IN THE CORN BUNTING

Polygyny in territorial birds is predicted to arise through random female settlement when females do not suffer costs to polygyny and male territories are homogeneous with respect to female preferences. Data from a study of corn buntings, Miliaria calandra, on North Uist, Scotland, supported the hypothesis that females settle in a Poisson distribution amongst males when such conditions are met. Corn bunting nests were not spatially or temporally more spaced than predicted by chance, suggesting that females did not compete for resources. Differences between males in the composition of their territories did not explain the variation in male mating success. Primary and secondary females did not select territories in the same rank order and primary females did not settle earlier than monogamous females, as would have been predicted if territory or male quality had been important in determining where females settled.