Winter Prey Caching by Northern Hawk Owls in Minnesota

—Northern Hawk Owls (Surnia ulula) have been reported to cache prey during the breeding season for later consumption, but detailed reports of prey caching during the non-breeding season are comparatively rare. We provided prey to four individual Northern Hawk Owls in wintering areas in northeastern Minnesota during 2001 and 2005 and observed their caching behavior. These owls cached 93% (n 14) of prey items presented to them and consumed one item immediately after capture. A number of bird species relocate stored food by remembering the spatial locations of caches. Prominent landmarks (dead trees larger than the surrounding vegetation, sites concealed in the snow next to a utility pole or clump of grass) or sites near them were often selected for caching by Northern Hawk Owls and likely facilitate relocation of stored prey. Prey caching during winter allows exploitation of temporary increases in prey abundance and may aid in survival during times of food shortage or adverse weather. Received 24 October 2006. Accepted