MATE CHOICE AND REPRODUCTIVE SUCCESS IN THE DOMESTICATED BUDGERIGAR, MELOPSITTACUS-UNDULATUS

Female budgerigars that had been given the opportunity to choose their mace laid more promptly, produced a higher number of eggs and reared a higher number of fledgings than females that had been denied the pos sibility to choose a mate and had been paired at random. In addition, males of self-selected pairs performed courtship singing at higher rat e than those of random pairs. However, in the following brood most dif ferences disappeared as the number of eggs laid and young fledged incr eased in the random group and the race of courtship singing decreased in the self-selected group. It appears, therefore, that choosy females do enjoy a reproductive advantage even though they do not necessarily choose genetically superior males. Male budgerigars singing too littl e might be simply unable to stimulate ovarian development and sexual r esponse of the female.