Extra-pair paternity in the socially monogamous orange-tufted sunbird (Nectarinia Osea Osea)

The frequency of extra-pair paternity (EPP) was examined by DNA fingerprint ing with R.18.1 and 33.6 multilocus minisatellite probes, in part of a popu lation of orange-tufted sunbirds consisting of 55 observed breeding pairs. Out of a total of 358 nesting attempts, sunbird pairs successfully nested o n average 2.6 (+/-1.4 SD) times per nesting season, and produced on average 2.8 (+/-0.4 SD) broods. Of the 25 breeding pairs and 88 nestlings examined for DNA, 12 (48%) of the females had extra-pair young, and 17 (36%) of the broods had at least one EPP chick. Of the nestlings 20 (23%) were sired by extra-pair males. The average number of EPP chicks per three-egg clutch wa s significantly higher (0.857, N = 25) than the number per two-egg clutch ( 0.286, N = 11). Breeding success among nesting attempts and among breeding pairs did not differ in relation to paternity. Of the seven extra-pair male s identified, six were paired males from neighboring territories and one wa s a floater (an unpaired male without its own territory). Two of the extra- pair males were themselves cuckolded. The frequency of extra-pair paternity was found to be positively correlated with breeding synchrony. Territorial fidelity over two consecutive breeding seasons was high; 48% of the female s, as opposed to 33% of the males, reoccupied their previous territories. R emating may thus occur with a familiar bird.