Morphology ³

Northern Hawk Owls' plumage is compact, in contrast to the down feathers of boreal owls (Voous, 1988). They are dark chocolate in color with white spots. The breast and belly regions are creamy white crossed by horizontal, cinnamon brown bars. Their poorly developed facial disks are framed by black lines. Often referred to as the "earless" owl, they lack true ear tufts; the external ear openings are elliptical (de la Torre, 1990). Both legs are fully feathered (Duncan and Duncan, 1998).

"cool facts" ⁴

A bird of boreal forests, the Northern Hawk Owl is distinctive among owls for its morphology and behavior. In winters of food scarcity, it irrupts southward into southern Canada and the northern United States. The Northern Hawk Owl can detect prey by sight at a distance of up to 800 meters (half a mile). Though it is thought to detect prey primarily by sight, the Northern Hawk Owl can find and seize prey under 30 cm (1 foot) of snow.

Habitat ⁵

Surnia ulula lives primarily in dense coniferous or coniferous-deciduous forests, which adjoin open areas. It prefers mountainous ranges where open areas and perches are readily available. The abundance of prey dictates location of habitats (Duncan and Duncan, 1998). This species will not inhabit dark impenetrable spruce-fir forests

(Voous,1988).

Trophic strategy ⁶

Northern Hawk Owls prey on small mammals (voles, lemmings, mice, shrews, snowshoe hares, cottontails, moles, squirrels and rats). During the summer, they consume primarily rodents, and in the winter they shift to birds (ptarmigan and grouse). The extent to which they prey on birds is unknown. They share similar hunting habits with boreal owls. They hunt both during the day and the night (Duncan and Duncan, 1998).

Uses ⁷

In particular during the summer months, the Northern Hawk Owl plays a significant role in controlling the rodent population; rodents may make up as much as 90% of their diet (Lockshaw, 2001).

Sources and Credits

1. (c) roy pilcher, some rights reserved (CC BY-NC), uploaded by roy pilcher
2. (c) Krzysztof Blachowiak, some rights reserved (CC BY), https://www.flickr.com/photos/blachowiak/10885279335/
3. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31425085
4. Public Domain, http://eol.org/data_objects/27672604
5. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31425084
6. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31425089
7. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31425092

More Info

• iNaturalist.ca taxon page
• Animal Diversity Web
• Biodiversity Heritage Library
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