|Northern Hawk Owl (Surnia ulula)||
Northern Hawk Owls are compact, medium sized owls of northern areas. They have bright yellow eyes, broad vertical black stripes down either side of their faces and black chins. Their beaks are two-tone: the lower mandible and lower edging of the upper mandible are both black, while the upper portion of the upper mandible is bone coloured. This gives the beak a decidedly narrow, sharp appearance.
At first glance, these birds look more like accipiters (forest hawks) or falcons than owls. This is due to their body shape. Designed for fast, dynamic flight, these owls have more pointed wings and longer tails than other North American owls. Hawk Owls also lack the classic parabolic facial disc one would expect. Like Snowies (Nyctea scandiaca), Hawk Owls are diurnal hunters (hunting during daylight hours) and predominantly utilize their keen sense of eyesight rather than their acute sense of hearing to locate and capture prey (which include rodents, small birds and rarely, larger prey such as rabbits).
Hawk Owls are most closely related to Burrowing Owls (Athene cunicularia). Although this may seem odd at first, both species share a common characteristic - they show extremes in tarsus length (the bone between ankle and foot). While Burrowing Owls have evolved long legs helpful in prairie habitation, Hawk Owls have evolved very short tarsi perfect for perching at treetops. The short length of the leg bones allows these birds to perch in a unique way: instead of placing their feet facing downward to grip, Hawk Owls can actually grasp a tree's peak from either side (providing the trunk is not too thick). This method provides better grip and more balance. The short tarsal length minimizes the effects of stress imposed on the legs from the bird's body weight. Longer tarsi are more likely to buckle under such pressure. Of course, this useful characteristic has its downside - it makes banding Hawk Owls difficult. Special bands are produced and only put on when the bird is fully grown.
The Owl Foundation lost most of its Hawk Owls in the summer of 2002 when West Nile Virus arrived in southern Ontario. Luckily, our most reliable breeding pair were successfully quarantined from the epidemic and, in their now meshed enclosures, continue to produce 4-7 chicks each year and foster any orphaned Hawk Owls.
Powerful storms and tree felling in northern areas account for the majority of young Hawk Owls received by The Owl Foundation each year. Sometimes these chicks are injured as they fall through tree branches to the ground. Others fall from logging trucks as nest trees are transported away for processing. Many fledglings, just learning the principles of flight and ignorant of cars, are struck by vehicles.
Potentially releasable Hawk Owls are trained in The Owl Foundation's "Serpentine" unit; an amalgamation of six shorter release training units into a 288' twisting enclosure. Here they gain the muscle tone and endurance they will require in the wild to survive. They hunt live mice and quail until spring, when releasable birds are transported to and freed in northern Ontario.
Hawk Owls do not hoot. The predominant vocalization at The Owl Foundation is an ascending scream. Excited birds will produce a warbling cry. It is very distinct and often incites other Hawk Owls to vocalize. The trilling call (below) is used mainly in spring. It sounds very much like the low trill of an Eastern Screech Owl (Asio otus), though it is much louder. This is a wooing call used to find a mate and likely doubles as a territorial vocalization. Other calls include a short (usually in series) chirping scream and an alarm call.
Owl vocalizations recorded by Kara Kristjanson.
Unless otherwise stated, all photographs and sound files are the property of The Owl Foundation.
No images or sounds on this website are to be duplicated in any way without express written permission
from the party to which they belong.
If you are interested in receiving quality versions, please contact The Owl Foundation.