Saturday, December 8, 2012

Northern Hawk-Owl

Looking through my blog, I am surprised I have not discussed the Northern Hawk Owl. This owl is rare but regular, mostly in northeastern Minnesota. They can be hard to find during years when they have not irrupted out of northern Canada, but good numbers can be seen when they invade. In 2001, I observed seven during a single afternoon. A few nesting records exist for northeastern Minnesota bogs (Eckert).

Hawk owls breed in northern forests of both the Old and New Worlds. Nevertheless, they are one of the least studied birds of North America. Almost no nests have been studied on our continent. These birds are atypical among owls in that they feed during the day and, in many ways, resemble Accipiter hawks. They often perch atop prominent trees. Unlike other owls, where the females are larger than males, hawk owl sexes are similarly sized.

Hawk owls can locate prey under up to 30 cm of snow cover (presumably by sound). Their invasions of southern areas are thought to be after periods of high reproductive success followed by severe winters with relatively few prey, but little is known about these population swings. These owls consume small rodents, grouse, ptarmigan, and rabbits (Duncan and Duncan 1998).

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