Northern Hawk Owl - Surnia ulula
Calls - Surnia ulula
[For help with terms used in the description, see parts of an owl. For general characteristics common to most owl species, see owl physiology.]
Description: A medium sized Owl. Facial disc is whitish,
broadly rimmed blackish at sides. Eyebrows are white, and eyes are pale yellow
(golden yellow in juvenile). Upperparts are dark grey to dusky greyish-brown,
with crown densely spotted whitish and nape with indistinct false eyes.
Mantle and back are dusky grey with some whitish dots. Scapulars are mainly
white, forming rather broad white bands across shoulder. Flight feathers are
dark grey-brown with rows of white spots. the Tail is long and graduated and
dark greyish-brown with several narrow whitish bars. Underparts are whitish,
barred with Greyish-brown. Legs and toes are feathered.
Size: Length 36-41cm. Wing length 22-25.2cm.
Weight males 273-326g, females 306-392g.
Habits: A largely diurnal bird. Flight is straight with
rapid wingbeats and open-winged glides; often hovering, perching in exposed
sites such as a treetop or post. Flicks tail when excited. Not social - seen
mostly singly or in pairs.
Voice: Typical male call is a rapid, melodious, purring
trill of up to 14 seconds long, which consists of about 11 to 15 notes per
second. It begins softly, rises slightly in pitch and increases to a vibrating
trill before breaking off abruptly. This is repeated at various intervals. Females utter a similar, higher-pitched, less clear song. Both sexes
give a piercing kiiiiirrl or a kestrel-like kwikikikikkik call
when excited. Screeching calls are also uttered. A soft uhg or uih is given as
contact between pairs. Young beg with a drawn-out chchchiep.
Hunting & Food: Takes mainly small mammals as prey,
mostly lemmings and voles. Will also take birds, frogs and occasionally fish.
Prey weight is normally below 70g. Hunts by searching from a lookout, then
quickly flying to swoop down on prey. Has been observed hovering also.
Breeding: Male advertises potential nest sites, and the
female selects one. Nests in Cavities on top of broken trunks, natural tree
hollows, abandoned holes of large woodpeckers. Will accept nest boxes,
and occasionally use a stick nest of a larger bird. Laying normally occurs in
April and the first half of May. Clutch sizes are usually between 5 and 13 eggs,
each 36-44mm x 29-34.4mm. Eggs are laid at 1-2 day intervals, and incubated
by the female alone for 25-30 days. During this time, the male feeds the female.
After hatching, the chicks are brooded for 13-18 days, and leave the nest at
23-30 days, and can fly well by the time they are about 5-6 weeks old. They
become independent of their parent's care towards the end of August. They become
sexually mature towards the end of their first year. Pairs are monogamous during
Habitat: Open boreal coniferous forest with clearings and
moors in lowlands or mountains. Hunts in semi-open country with scattered trees
or groups of trees.
Distribution: Eurasia from Norway, Sweden and Finland east
through Siberia to Kamchatka, Sakhalin, and North China, in Central Asia south
to Tien Shan. North America from Alaska east to Labrador.
Moves widely within its area of distribution, breeding where food is abundant.
In some Autumns, invasions (mainly juveniles) occur in areas south of its normal range.
Distribution of the Northern Hawk Owl Surnia ulula
Status: Not threatened or endangered.
Original Description: Linnaeus, Carolis. 1758. Systema Naturae ed. 10, p. 93.
S. u. ulula,
S. u. caparoch,
S. u. tianschanica
Page compiled by Deane P. Lewis. Page last updated 2012-08-13
OwlPages.com Owl Species ID: 180.010.000