Low levels of extra-pair paternity in the long-lived colonial Alpine swift Tachymarptis melba

Abstract

It has been suggested that a high aerial lifestyle makes it difficult for males to limit mating opportunities for their partners. This would explain the particularly high levels of extra-pair paternity (EPP) observed in several species of swallows and martins (Hirundinidae, Passeriformes), but EPP in the other bird lineages with a high aerial lifestyle, such as swifts (Apodiformes), is largely unknown. Here, we investigated EPP in the Alpine swift Tachymarptis melba. We found nine cases of EPP in 9 broods out of 214 (4.2%) nestlings and 87 (10.3%) broods analysed with information on fathers. This low incidence of extra-pair paternities is similar to the only estimate reported so far in Apodiformes (i.e. 4.5% of nestlings in the common swift Apus apus). We suggest that life-history traits (biparental incubation, long lifespan, and frequent mate retention across years), rather than their aerial lifestyle, may explain the low incidence of EPP in swifts.