Northern hawk-owl
Northern hawk-owl | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Strigiformes |
Family: | Strigidae |
Genus: | Surnia |
Species: | S. ulula
|
Binomial name | |
Surnia ulula | |
Range of S. ulula Resident Non-breeding
| |
Synonyms | |
Strix ulula Linnaeus, 1758 |
The northern hawk-owl or northern hawk owl (Surnia ulula) is a medium-sized
Taxonomy
The northern hawk-owl was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Strix ulula.[3] The owl is now the only species placed in the genus Surnia that was introduced in 1805 by André Duméril.[4][5] The type species was designated by George Robert Gray in 1840 as the northern hawk-owl.[6][7] The genus name is of unknown etymology and may simply have been invented by Duméril. The specific epithet ulula is Latin for a "screech owl".[8]
A
Three subspecies are recognised:[5]
- S. u. tianschanica Smallbones, 1906 – central Asia to northern China and northern Mongolia[10]
- S. u. ulula (Linnaeus, 1758) – northern Eurasia
- S. u. caparoch (Müller, PLS, 1776) – northern North America
Description
Male northern hawk-owls are generally 36–42.5 cm (14.2–16.7 in) long and weigh about 300 g (11 oz). Females are slightly bigger with a length of 37.2–44.7 cm (14.6–17.6 in) and a mass of about 340 g (12 oz). Both male and female have similar wingspans of about 45 cm (18 in). 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.[11]
The northern hawk-owl has been said to resemble a hawk in appearance and in behavior. In North America, its appearance in flight is often considered similar to a Cooper's hawk (Accipiter cooperii). It has been suggested that this may be because the hawk-owl may partially fill an important diurnal niche similar to that of day hunters such as hawks.[12]
Vocalization
Various calls are 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.[11]
When alerting to danger, the northern hawk-owl lets out a sound similar to rike, rike, rike, rike. It also releases a high-pitched scream followed by a yip when an intruder is near to the nest. To warn of impending dangers to a
Distribution and habitat
Three
Occasionally, S. u. caparoch can extend its territory as far south as northern
Northern hawk-owls are unevenly distributed and highly variable throughout the
Behaviour and ecology
Breeding
The northern hawk-owl generally starts its mating rituals at the beginning of March.
For the most part, the female northern hawk-owl does the incubating of the eggs, whilst the male forages for food. Once the chicks have hatched their roles shift drastically. At about two weeks into the chicks' lives, the female starts to leave the nest for long spans of time (5 hours or more). This span of time is presumably when the female hunts. The male, however, will guard the nest diligently until the chicks leave. When predators (usually other raptors) 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 which allows less parental supervision, they will leave the nest. This occurs on average after their 21st day, and can begin as early as mid-June. After this the female will provide most of the care. However, the male will remain close and will still feed his young on occasion.[16] The northern hawk-owl has also been known to nest on cliffsides. It has little fear of humans, and will attack if the young are approached too closely.
Food and feeding
The northern hawk-owl feeds on a variety of prey, which can include small
Other animals that are important prey items for the northern hawk-owl include the
The northern hawk-owl is a partially
The type of
Conservation and status
Due to its low density occurrence, sporadic fluctuations, and remote breeding locations,[20] the northern hawk-owl is one of the least studied and poorly understood birds in North America.[11][21] As a result, it is almost impossible to properly estimate its numbers.[20][22]
In Yukon, northern hawk-owl densities were estimated to be between zero and six pairs per 100 km2 (39 sq mi).[17] Despite these low densities, the North American population is thought to be fairly large given that they occur throughout the boreal forest.[20] Duncan and Harris (1997) estimated that this population contains between 10,000 and 50,000 pairs.[21]
Populations are known to fluctuate with cycles of small rodents [13][14][22] and irruptions are known to occur in sub-boreal regions throughout the world.[13][20][23] 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.[13] Irruptions can be used as indicators of small mammal abundance [24] and in eastern North America, southern irruptions have been linked with low densities of red-backed voles in the high boreal forest.[23]
In North America, over 50% of the northern hawk-owls' breeding territory occurs in non-commercial
The status and conservation of this species is uncertain.[14] 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.[20] Compared to the nineteenth century, southern irruptions in the New and Old World appear to have declined.[13] Also, North American populations seem to be declining, although no proper documentation exists to confirm this trend.[11][20] In Canada, it was ranked 85th overall to set conservation, research, or monitoring priorities.[25] Downes et al. (2000) considered the hawk-owl to be of medium concern, but with a high priority to improve monitoring.[26]
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.[27]
References
- . Retrieved 13 November 2021.
- ^ "Appendices | CITES". cites.org. Retrieved 14 January 2022.
- ^ Linnaeus, Carl (1758). Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis (in Latin). Vol. 1 (10th ed.). Holmiae (Stockholm): Laurentii Salvii. p. 93.
- ^ Duméril, A. M. Constant (1805). Zoologie analytique : ou, Méthode naturelle de classification des animaux; endue plus facile a l'aide de tableaux synoptiques (in French). Paris: Allais. p. 34. The book bears the date of 1806 on the title page but was actually published in 1805. See: Gregory, Steven M.S. (2010). "The two 'editions' of Duméril's Zoologie analytique, and the potential confusion caused by Froriep's translation Analytische Zoologie" (PDF). Zoological Bibliography. 1 (1): 6–8.
- ^ Rasmussen, Pamela, eds. (January 2021). "Owls". IOC World Bird List Version 11.1. International Ornithologists' Union. Retrieved 22 May 2021.
- ^ Gray, George Robert (1840). A List of the Genera of Birds : with an Indication of the Typical Species of Each Genus. London: R. and J.E. Taylor. p. 5.
- ^ Peters, James Lee, ed. (1940). Check-List of Birds of the World. Vol. 4. Cambridge, Massachusetts: Harvard University Press. p. 126.
- ISBN 978-1-4081-2501-4.
- hdl:2346/93048.
- ^ Smallbones, G. (1906). "Surnia ulula tianschanica n. sp". Ornithologische Monatsberichte (in German). 14 (2): 27–29.
- ^ doi:10.2173/bna.356.
- ^ S2CID 24152225.
- ^ ISBN 0262220350.
- ^ a b c d König C, Weick F, Wink M. 2008. Owls of the world. London: Christopher Helm.
- ^ S2CID 86012378.
- ^ a b c d e f g Kertell, Kenneth (1986). "Reproductive biology of Northern Hawk-Owls in Denali National Park, Alaska". Raptor Research. 20 (3/4): 91–101.
- ^ JSTOR 1368997.
- ^ "Surnia ulula (Northern hawk owl)". Animal Diversity Web.
- ^ König, Claus, Friedhelm Weick, and Jan-Hendrik Becking. Owls of the World. 2nd ed. Bloomsbury Publishing, 2009. Web. 23 May. 2023.
- ^ a b c d e f Duncan PA, Committee on the Status of Endangered Wildlife in Canada (1992). Status report on the northern hawk-owl, Surnia ulula. Ottawa: Committee on the Status of Endangered Wildlife in Canada.
- ^ a b Duncan PA, Harris WC (1997). "Northern Hawk-Owls Surnia ulula caparoch and forest management in North America: A review". Journal of Raptor Research. 31 (2): 187–190.
- ^ ISBN 0874745608.
- ^ .
- .
- ^ Dunn EH. (1997) Setting priorities for conservation, research and monitoring of Canada's landbirds. Tech. Rep. Ser. No. 293. Can. Wildl. Serv. Ottawa, ON. Cited in: Duncan JR, Duncan PA, Poole A, editor. 1998. Northern Hawk-Owl Surnia ulula, The Birds of North America Online [Internet]. Ithaca: Cornell Lab of Ornithology.
- ^ Downes CM, Dunn EH, Francis CM. (2000) Canadian landbird monitoring strategy: Monitoring needs and priorities into the new millennium. Partners In Flight-Canada, Ottawa.
- S2CID 86012378.
External links
- "Northern Hawk-Owl media". Internet Bird Collection.
- Northern Hawk-Owl Species Account – Cornell Lab of Ornithology
- Northern Hawk-Owl – eNature.com
- Northern Hawk-Owl Stamps at bird-stamps.org[usurped]
- Surnia ulula in Field Guide: Birds of the World on Flickr
- "Surnia ulula". Avibase.
- 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 photo gallery at VIREO (Drexel University)