Age-dependent diet choice in an aviantop predator

Age-dependent breeding performance is arguably one of the best-documented phenomena in ornithology.The existence of age-related trends has major implications for life-history theory, but the proximatereasons for these patterns remain poorly understood. It has been proposed that poor breeding performanceof young individuals might reflect lack of foraging skills.We investigated this possibility in a medium-sized,powerful raptor-the northern goshawk Accipiter gentilis. Male goshawks are responsible for providing theirfemales and their offspring with food.We hypothesized that young males may generally show poor breedingperformance or even delay breeding, because they lack the experience to hunt efficiently-especially, theirprincipal avian prey, the feral pigeon Columba livia. Our study exploited a rare