northern hawk-owl densities were estimated to be between zero and six pairs per . Despite these low densities, the North American population is thought to be fairly large given that they occur throughout the boreal forest. Duncan and Harris (1997) estimated that this population contains between 10,000 and 50,000 pairs. Populations are known to fluctuate with cycles of small rodents and irruptions are known to occur in sub-boreal regions throughout the world. In Scandinavia, populations have been reported to vary from a few hundred birds in certain years to over 4000 birds in others and even up to 10,000 breeding pairs in optimal years. Irruptions can be used as indicators of small mammal abundance and in eastern North America, southern irruptions have been linked with low densities of red-backed voles in the high boreal forest. In North America, over 50% of the northern hawk-owls' breeding territory occurs in non-commercial boreal forests and as long as nothing threatens their northern habitats, no known factors challenge their existence. However, it is unknown what effects modern forestry would have on population levels because although it would decrease nesting localities, it would simultaneously create ideal habitat for Microtus prey. Fire suppression by humans is believed to negatively affect northern hawk-owl populations by reducing open areas for hunting and dead wood to nest in. The status and conservation of this species is uncertain. A report by the Committee On the Status of Endangered Wildlife In Canada (COSEWIC) recommended that no designation be assigned for the northern hawk-owl. Compared to the nineteenth century, southern irruptions in the New and Old World appear to have declined. Also, North American populations seem to be declining, although no proper documentation exists to confirm this trend. In Canada, it was ranked 85th overall to set conservation, research, or monitoring priorities. Downes et al. (2000) considered the hawk-owl to be of medium concern, but with a high priority to improve monitoring. In falconry The northern hawk-owl is considered a falconry bird in Ontario, and may be used to hunt small game with a proper license. References External links Northern Hawk-Owl Species Account – Cornell Lab of Ornithology Northern Hawk-Owl – eNature.com Northern Hawk-Owl Stamps at bird-stamps.org Northern Hawk-Owl information at owlpages.com Northern Hawk-Owl profile at the Government of Canada Species at Risk Public Registry Northern hawk-owl. Video of male, female and chicks. northern hawk-owl Holarctic birds northern hawk-owl northern hawk-owl