The Boreal owl is a small secretive bird of prey that lives in dense forests across northern North America and the northern regions of Eurasia. It is brown above, with white flecking on the shoulders. Its underparts are whitish streaked with rust. The head is large, with yellow eyes and a white facial disc, and a "surprised" appearance. Young birds are chocolate brown in color.
Boreal owls breed across northern North America and Eurasia. They are partly migratory especially northern populations that make local movements during the winter. Preferable habitats include dense coniferous forests, however, these owls may also be found in mixed-species and deciduous forests.
Boreal owls are generally solitary birds and can be seen with their mates only during the breeding season. They are largely nocturnal, though, in the northernmost parts of their range, Boreal owls are forced to hunt during daylight because of the very short nights in summer. They hunt from a perch waiting silently for prey to pass by. Once the prey is detected, they swoop down and catch it with the talons. Boreal owls fly with rapid wing beats but may also glide and even hover for a few seconds. Their flight is relatively noiseless and straight.
Boreal owls are serially monogamous and form pair bonds that last for one breeding season. However, there were cases of polygynous (one male to several females) and polyandrous (one female to more than one male) behavior. The breeding season occurs in March-July. Boreal owls nest mainly in abandoned woodpecker cavities, but may also use natural tree holes or even nest boxes. The female lays 3-6 white eggs and incubates them alone for 26-32 days; during this time she is fed by the male. Owlets are born blind and helpless. They grow quickly and their eyes open 10 days after hatching. At the age of one month owlets leave the nest but their parents continue to feed them approximately 4-6 weeks more. Reproductive maturity is usually reached when the young are 9 months old.
Boreal owls suffer from the loss of habitat particularly due to logging and agricultural expansion that destroy nest cavities and suitable habitats for foraging. Boreal owls also suffer from pesticides and predation by Tawny owls and martens which kill many nesting females.
According to the IUCN Red List the total Boreal owl population size is estimated to be around 700,000-2,400,000 mature individuals. The European population consists of 90,900-309,000 pairs, which equates to 182,000-619,000 mature individuals. Overall, currently this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
Boreal owls play an important role in their ecosystem. They control populations of small mammals, such as voles and mice, and also serve as a food item for local predators.