OLD, COLORFUL MALE YELLOWHAMMERS, EMBERIZA-CITRINELLA, BENEFIT FROM EXTRA-PAIR COPULATIONS

The frequency of extra-pair paternity was determined in broods of the yellowhammer using single-locus DNA fingerprinting. Of 32 analysed clu tches, 69% contained at least one extra-pair young. Out of 123 nestlin gs, 37% were extra-pair sired young. The extra-pair male could be assi gned to 23 (50%) nestlings. Successful extra-pair males were all at le ast 3 years old although both younger and older males suffered from ex tra-pair paternity. Extra-pair males were also significantly more colo urful than pair males, but did not differ in other characters. Colour did not differ between males with or without extra-pair young. The fre quency of extra-pair young was not related to breeding density and ide ntified extra-pair males were not necessarily nearest neighbours, givi ng further evidence that extra-pair males are not chosen at random. Si nce females do not obtain anything but sperm from extra-pair males, th e results suggest that females prefer older and more colourful males, contributing good or attractive genes, as indicated by their plumage. Consequently, old, colourful extra-pair males, and possibly females, a re likely to benefit from extra-pair copulations. (C) 1996 The Associa tion for the Study of Animal Behaviour.