Microsatellite typing reveals mating patterns in the brood parasitic great spotted cuckoo (Clamator glandarius)

Despite the interest that avian brood parasites provoke due to their reproductive strategy, and the wealth of published studies, their mating system is one of the least known aspects of their natural history. This study describes the first attempt to use genetics to characterize mating patterns in a brood parasite, the great spotted cuckoo (Clamator glandarius). We developed a set of microsatellite markers for this species that allowed us to determine the parentage of 78% of the chicks sampled, with a high probability of certainty (false parental inclusion probability, PFI = 2 × 10). Parentage analyses allowed us to determine mating patterns in the population, to show for the first time that there were several females laying in the same study site and sharing host nests, and that females used nests of two different host species in the same season. A total of 70% of the inferred mating relationships can be considered monogamous, and the rest were cases of genetic polygamy, although of unknown social structure. To ease parentage analyses, adult birds were successfully sexed using a combination of sexspecific PCR primers and SSCP techniques before parentage assignment.