Northern Hawk Owl

Surnia ulula

Description 4

Male northern hawk-owls are generally 36–42.5 cm (14.2–16.7 in) long and weigh 300 g (11 oz). Females are slightly bigger with a length of 37.2–44.7 cm (14.6–17.6 in) and a mass of about 340 g (12 oz). Both male and female have similar wingspans of about 45 cm (18 in). The northern hawk-owl plumage is relatively dark brown with an off white spotting pattern on all dorsal parts of the body with the exception of the back of the neck which boasts a black v-shaped pattern. The underbelly is generally white or off-white which continues to the toes with brown bands on the breast and stomach. It also boasts a long tail with brown banding. The northern hawk-owl has a smokey white face with a black border, a flat head, yellow eyes and a yellow curved beak.

The northern hawk-owl has been said to resemble a hawk in appearance and in behavior. In North America, its appearance in flight is often considered similar to a Cooper's hawk (Accipiter cooperii). It has been suggested that this may be because the hawk-owl may partially fill an important diurnal niche similar to that of day hunters such as hawks.

"cool facts" 5

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.

Breeding 4

The northern hawk-owl generally starts its mating rituals at the beginning of March. After calling and pairing is complete the northern hawk-owl will build a nest and start to lay eggs. On average the northern hawk-owl will lay 3–11 eggs per brood. The nest sites are usually the tops of hollow stumps of old dead spruce trees. These nesting sites are usually 2–10 m (6.6–32.8 ft) above ground for the North AmericanS. u. caparoch and approximately 4–5 m (13–16 ft) above ground for the EurasianS. u. ulala. The specific dates of egg appearance can be quite variable depending on locality. In central Canada eggs are usually laid from March 30 to the 5th of June. In Newfoundland the appearance of eggs occurs later, between May 9 and June 11. In Finland however, eggs can be found anywhere between the 30th of March to the 23rd of June.

For the most part the female northern hawk-owl does the incubating of the eggs whilst the male forages for food. Once the chicks have hatched their roles shift drastically. At about two weeks into the chicks lives the female starts to leave the nest for long spans of time (5 hours or more). This span of time is presumably when the female hunts. The male however, will guard the nest diligently until the chicks leave. When predators (usually other raptors) fly nearby, the male will sometimes chase them away from the nest if they feel it is necessary. Once the owlets have grown to a size which allows less parental supervision, they will leave the nest. This occurs on average after their 21st day, and can begin as early as mid-June. After this the female will provide most of the care. However the male will remain close and will still feed his young on occasion.

The northern hawk-owl has also been known to nest on cliffsides. It has little fear of humans, and will attack if the young are approached too closely.

Sources and Credits

  1. (c) Michael Klotz, some rights reserved (CC BY-NC),
  2. (c) Krzysztof Blachowiak, some rights reserved (CC BY),
  3. (c) Matti Suopajärvi, some rights reserved (CC BY-NC-SA),
  4. (c) Wikipedia, some rights reserved (CC BY-SA),
  5. Public Domain,

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Animal Bird
Color grey
Bird Strigidae (owl)