Great Grey Owl - Feeding

Feeding

These birds wait, listen, and watch for prey, then swoop down; they also may fly low through open areas in search of prey. Their large facial disks, also known as "ruffs", focus sound, and the asymmetrical placement of their ears assists them in locating prey, because of the lack of light during the late and early hours in which they hunt. On the nesting grounds, they mainly hunt at night and near dawn and dusk; at other times, they are active mostly during the night. They have excellent hearing, and may locate (and then capture) prey moving beneath 60 cm (2 feet) of snow in a series of tunnels solely with that sense. They then can crash to a snow depth roughly equal to their own body size to grab their prey. Only this species and, more infrequently, other fairly large owls from the Strix genus are known to "snow-plunge" for prey, a habit that is thought to require superb hearing not possessed by all types of owls. Unlike the more versatile eagle and horned owls, Great Gray Owls rely almost fully upon small rodents, with voles being their most important food source. Locally, alternative prey animals (usually comprising less than 20% of prey intake) include hares, moles, shrews, weasels, thrushes, grouse, Gray Jays, small hawks and ducks. Although seldom preyed upon, Great Gray Owl nestlings and juveniles may themselves fall prey to bears, fishers, and large hawks, especially Northern Goshawks; while adults may fall prey to Bubo owls, Golden Eagles and lynxes.

The song of the male is a series of very deep, rhythmic hoots whoo, whoo, whoo, whoo, whoo.... At other times, adults are normally silent. The young may chatter, shriek or hiss.