Introduction

Presumed first-winter male Snowy Owl, Wolfe Island, ON, February.

Figure 1. Breeding and wintering distribution of Snowy Owls in North America.

Editor's Note 01/06: Formerly placed in genus Nyctea -- based on plumage, osteological (skull) characters, and DNA -- this species is now (based on new genetic evidence) considered closely related to the Bubo owls and nested in that genus. Future revisions of this account will reflect this change.

This large, northern circumpolar owl breeds in open terrain from near tree line to the edge of polar seas, wintering regularly south to the northern U.S. and sporadically beyond. A nomadic species and often unpredictable migrant, its movements are thought to relate to the variable abundance of its main prey species, lemmings. As a winter migrant, it is more regular and abundant in the northern Great Plains than it is to the east, west and south of there. It nests on windswept hummocks and boulders in the arctic barrens, producing large clutches and up to a dozen young per nest where food is abundant. Where food is scarce, it may refrain from breeding for a year or more.

Differing from most owls in being largely diurnal, the Snowy Owl hunts in all weather during winter and the continuous light of arctic summer, at times consuming more than 1,600 lemmings a year. Generally monogamous and territorial, it is often vocal and aggressive in defense of territory and young, sometimes striking humans and even wolves that stray near nests. Adult males are noticeably smaller and paler than adult females, immatures being the most heavily marked as a rule.

This owl is probably the oldest bird species recognizable in prehistoric cave art. Audubon’s 1829 painting of a pair of Snowy Owls depicts the dimorphism in size and plumage of the two sexes. Although these birds often hunt by day, Audubon included them in the only nocturnal scene that he painted.