Associations between gamebird releases and generalist predators

1. The release of more than 40 million captive-bred Pheasants and Red-legged Partridges in Britain annually represents a significant addition to the potential food resource base for predators and scavengers. If this extra food availability subsidises predator populations, gamebird releases could increase predation pressure on other wild birds, affecting their populations. 2. Using three extensive datasets, we examined the spatial relationships between reared and free-roaming gamebirds (Pheasant Phasianus colchicus and Red-legged Partridge Alectoris rufa), and explored spatial and temporal associations between these gamebirds and five species of avian predator (Buzzard Buteo buteo, Jay Garrulus glandarius, Raven Corvus corax, Magpie Pica pica, and Hooded Corvus cornix and Carrion Corvus corone Crows combined) in lowland rural Britain. 3. Patterns of spatial variation in the abundance of free-roaming gamebirds across Britain appear to be largely determined by gamebird releases, over and a...