Mass gained during breeding positively correlates with adult survival because both reflect life history adaptation to seasonal food availability

摘要: Both mass (as a measure of body reserves) during breeding and adult survival should reflect variation in food availability. Those species that are adapted to less seasonally variable foraging niches so where competition dominates breeding, will tend have higher increase via an interrupted response, because their demands become more unpredictable. They then produce few offspring per attempt, but trade this off with survival. In contrast, those occupy seasonal niche not gain remains predictable, as resources superabundant breeding. can also trade-off reduced We tested whether the predicted positive correlation between levels gained was present across 40 tropical bird measured over 10-year period West African savannah. showed greater had survival, controlling for annual (i.e. absolute availability) timing peak predictability availability), clutch size, migratory status phylogeny. Our results support hypothesis degree birds is probably indication life history adaptation: it may therefore be possible use index