Parent-offspring resemblance in colony-specific adult survival of cliff swallows

Abstract

Survival is a key component of fitness. Species that occupy discrete breeding colonies with different characteristics are often exposed to varying costs and benefits associated with group size or environmental conditions, and survival is an integrative net measure of these effects. We investigated the extent to which survival probability of adult ([greater than or equal to]1-year old) cliff swallows (Petrochelidon pyrrhonota) occupying different colonies resembled that of their parental cohort and thus whether the natal colony had long-term effects on individuals. Individuals were cross-fostered between colonies soon after hatching and their presence as breeders monitored at colonies in the western Nebraska study area for the subsequent decade. Colony-specific adult survival probabilities of offspring born and reared in the same colony, and those cross-fostered away from their natal colony soon after birth, were positively and significantly related to subsequent adult survival of the parental cohort from the natal colony. This result held when controlling for the effect of natal colony size and the age composition of the parental cohort. In contrast, colony-specific adult survival of offspring cross-fostered to a site was unrelated to that of their foster parent cohort or to the cohort of non-fostered offspring with whom they were reared. Adult survival at a colony varied inversely with fecundity, as measured by mean brood size, providing evidence for a survival-fecundity trade-off in this species. The results suggest some heritable variation in adult survival, likely maintained by negative correlations between fitness components. The study provides additional evidence that colonies represent non-random collections of individuals.