Un-paint it black: Avian prey as a component of the diet of nestling Hooded Crows Corvus cornix

The Hooded Crow (Corvus cornix) is often considered the main nest predator of many bird species, especially waterbirds. Such relationship should be particularly clear during the breeding season in wetlands, when the need to supply their nestlings with the highest quality foods forces predators to intensify their hunting activities. Hence, waterbirds should be their basic prey. We examined the composition of the diet of nestling Hooded Crows in the flooded river valley of the ``Ujscie Warty'' National Park in western Poland, which is a bird refuge of international importance and provides nesting habitat for numerous bird species. Despite the richness of potential avian prey, the dominant components of Hooded Crow nestlings' diet were insects, fish and plants. Contrary to expectations, birds were only supplementary to the diet of nestlings, and thus, we suggest that crows are likely to have only a marginal influence on nest failures of potential avian prey species in regions similar to the studied area.