Hawk-owl, Canadian owl, Hudsonian hawk-owl, Northern hawk owl
The Northern hawk-owl (Surnia ulula) is a medium-sized true owl that lives in the northern latitudes. It is one of the few owls that is neither nocturnal nor crepuscular, being active only during the day. It is sometimes called simply the hawk owl.
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 has 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.
Northern hawk-owls are found in North America and Eurasia. The North American subspecies spans from eastern Alaska through Canada to Newfoundland and in some areas extends south into the northern United States. The other two subspecies are found in Eurosiberia: one subspecies breeds in Central Asia reaching Xinjiang (China) and the other one resides across Siberia at its most eastern range. Northern hawk-owls are distributed throughout the boreal forest. They live mostly in open coniferous forests or coniferous forests mixed with deciduous species such as larch, birch, poplar, and willow. They are found in muskegs, clearings, swamp valleys, meadows, or recently burnt areas, and generally, avoid dense spruce-fir forests.
Northern hawk-owls are generally solitary but may also be seen in pairs. These birds are partially diurnal hunters, although they may hunt at varying times and do not appear to have a preferred hunting time. Whether the bird resides in Eurasia or North America, the strategy is usually similar. The Northern hawk-owl will perch and scour the immediate area for prey. As these owls are considered a search-oriented species they likely do not stay put for long if the site is not producing prey. The hawk-owl prefers open, forest-type environments when perching. When the bird attacks, it goes from a horizontal posture into a gliding dive. If the prey is further away, the hawk-owl will flap its wings a few times during the dive to increase distance. Northern hawk-owls have a variety of calls used by the different sexes in different situations. When attracting a mate the male usually lets out a rolled whistle of 'ulululululululul' and a sound similar to 'tu-wita-wit, tiwita-tu-wita, wita', when perching at a potential nest site. The female's call is usually less constant and more shrill. When alerting to danger, Northern hawk-owls let out a sound similar to 'rike, rike, rike, rike'. They also release a high pitched scream followed by a yip when an intruder is near to the nest. To warn of impending dangers to a fledgling, hawk-owls will let out a noise similar to 'ki ki kikikikiki'.
Northern hawk-owls are carnivores. They feed on small rodents and mammals, and a variety of birds.
Northern hawk-owls are serially monogamous; they form pair bonds that stay together for a single breeding season. Northern hawk-owls generally start their mating rituals at the beginning of March. After calling and pairing is complete the birds will build a nest and start to lay eggs. They nest in holes in trees, on cliffsides or sometimes use abandoned raptor or crow’s nest and even nest boxes. The female lays 5-13 white eggs which are incubation about 25-30 days. For the most part, the female does the incubating of the eggs while the male forages for food. Once the chicks have hatched their roles shift drastically. At about 2 weeks into the chicks' lives, the female starts to leave the nest for long spans of time, presumably for hunting. The male, however, will guard the nest diligently until the chicks leave. When predators fly nearby, the male will sometimes chase them away from the nest if he feels it is necessary. Once the owlets have grown to a size that allows less parental supervision, they will leave the nest. This occurs on average 21 days after hatching. After this, the female will provide most of the care. However, the male will remain close and will still feed his young on occasion. After fledging, the owlets remain in the nest territory for 6-8 weeks more and become independent at 75 days of age. Young Northern hawk-owls reach reproductive maturity when they are 1 year old.
Northern hawk-owls are not threatened globally; however, fire suppression by humans is believed to negatively affect this species population by reducing open areas for hunting and dead wood to nest in. Northern hawk-owls also suffer from poaching, accidental trapping, and collisions with power lines, vehicles, and trains.
According to the IUCN Red List, the total Northern hawk-owl population size is around 100,000-499,999 mature individuals. The North American population is estimated at approximately 60,000 individuals which equates to 40,000 mature individuals. The European population includes 10,400-53,900 pairs, which equates to 20,800-108,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
