COPULATORY-BEHAVIOR AND PATERNITY IN THE AMERICAN KESTREL - THE ADAPTIVE SIGNIFICANCE OF FREQUENT COPULATIONS

The adaptive significance of repeated withinpair copulations is not we ll understood. We analysed the copulatory behaviour of 16 pairs of sol itary-nesting American kestrels, Falco sparverius, in southern Quebec (Canada), and the achieved reproductive success (paternity) of 21 kest rel families determined by DNA fingerprinting, in terms of four hypoth eses. (1) The paternity assurance hypothesis, which suggests that male s copulate frequently to avoid being cuckolded, was rejected because t here were few extrapair copulation attempts (<1% of all copulations ob served), withinpair copulations were not timed during the fertile peri od and mate attendance did not increase as the fertile period approach ed, (2) The immediate material benefits hypothesis, which suggests tha t females trade copulations for food, was refuted-because copulations- most often occurred without food transfers, especially outside the fer tile period. (3) The female mate guarding of males hypothesis, which s uggests that females distract their mates from other mating opportunit ies by copulating frequently, was rejected because extrapair copulatio n attempts were infrequent, male and female solicitation frequencies w ere similar and females did not differ in the timing or frequency of s olicitations. (4) The mate assessment hypothesis,which suggests that a ssessment of mate quality is mediated via copulation, most closely pre dicted the behaviour observed since withinpair copulations were freque nt outside the fertile period and at pair formation, males and females solicited similar numbers of copulations and pairs did not differ sig nificantly in solicitation or copulation frequency. In line with this hypothesis we found that only one brood was extrapair, probably the re sult of mate replacement. (C) 1998 The Association for the Study of An imal Behaviour.