Great Gray Owl Biology

A Reference for North and Central American Owls

Name: Great Gray Owl – Strix nebulosa
Other Common Names: Dark Wood-Owl; Lapland Owl; Striped Owl; Sooty Owl; Spectral Owl.

Subspecies: There is only one race of Great Gray Owl in North America although there is a widespread northern Eurasian race.
S. n. nebulosa is the North American race of Great Gray Owl. Its approximate breeding range is shown on the range map. Winters in the breeding range but will also wander south. *See Movements.

Measurements and Weights:
Wingspan: 54 – 60 in.
Length: 24 – 33 in.
Tail: 11 3/4 – 13 3/4 in.
Average Weight: Male: 34 oz.
Average Weight: Female: 46 oz.

Description: This is the largest Owl in North America although it is not the most massive. Males and females are identical in plumage except that the females may appear slightly darker. Distinctively large facial disk of light gray with darker gray or brown concentric rings. Facial disk has a thin dark brown border that becomes white along the bottom edge. Has a black chin with white along the sides that run into the bottom white border of the facial disk (sometimes referred to as a “white mustache and black bow tie”). Conspicuous white eyebrows and lores. The Great Gray has a large round head and lacks ear tufts. The general colors of the upper parts are grayish-brown to sooty brown broken by transverse mottling of grayish-white and dark with scattered short dark streaks. The owl becomes more brown with age. The bottom portion of the wings (primaries and secondaries) and the tail are barred with dark and light gray. The under parts are a grayish-white with dark grayish-brown streaks. The iris of the eyes are lemon yellow and the bill is bright yellow to pale olive green.

Young: Initially the young have a grayish down above and white down below. The juveniles are olive-brown with dark bars and white spots above. Light gray- white below with dark bars; bold black facial marks. Adult plumage develops over the first 5 months but first year birds have white tipped flight feathers.