Rough-legged buzzard
Rough-legged buzzard | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Accipitriformes |
Family: | Accipitridae |
Genus: | Buteo |
Species: | B. lagopus
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Binomial name | |
Buteo lagopus (Pontoppidan, 1763)
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Subspecies[2] | |
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Range of B. lagopus Summer Winter
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The rough-legged buzzard (Europe) or rough-legged hawk (North America) (Buteo lagopus) is a medium-large bird of prey. It is found in Arctic and Subarctic regions of North America, Europe, and Russia during the breeding season and migrates south for the winter.[3] It was traditionally also known as the rough-legged falcon[4] in such works as John James Audubon's The Birds of America.
Nests are typically located on cliffs, bluffs or in trees.
Description
This fairly large raptorial species is 46–68 cm (18–27 in) with wingspan ranging from 120 to 153 cm (47 to 60 in).
Its feet are feathered to the toes as an adaptation to its Arctic home range. Its scientific name reflects this feature; the genus name Buteo is the Latin name of the common buzzard, and lagopus, is derived from Ancient Greek lago (λαγως), meaning "hare", and pous (πους), "foot".[15][16] Its talons are relatively small, reflecting their preferred choice of prey.
Distinguishing characteristics in all plumages include long white tail feathers with one or more dark subterminal bands. The wing tips are long enough to reach or extend past the tail when the animal is perched.[3] The common buzzard can be similar-looking, with a similar long-tailed shape and can be notoriously variable in plumage. The rough-legged is longer-winged and more eagle-like in appearance. The red-tailed hawk is chunkier-looking and differs in its darker head, broader, shorter wings, barring on the wings and the tail, dark leading edge to the wings (rather than black wrist patch) and has no white base to the tail. The ferruginous hawk is larger, with a bigger, more prominent bill and has a whitish comma at the wrist and all-pale tail.[17]
It is the only hawk of its size (other than the very different-looking osprey) to regularly hover over one spot, by beating its wings quickly.
Taxonomy
The rough-legged buzzard is a member of the genus Buteo, a group of moderately large raptors exhibiting broad wings, short tails and wide robust bodies.[3][18] This group is known as buzzards in Europe but referred to as hawks in North America.[3]
There are at least three recognized subspecies of Buteo lagopus:
- B. l. lagopus is the nominate subspecies. It breeds in northern Europe and Asia and has relatively dark plumage. The dorsal feathers are a homogeneous brown colour, contrasting well with the paler head.[3]
- B. l. sanctijohannis breeds in North America. It has pale, speckled dorsal plumage and is slightly smaller than B. l. lagopus.[3]
- B. l. kamtchatkensis breeds from north Siberia to Pacific North America. It has paler plumage when compared with B. l. sanctijohannis and it is, on average, the largest of the three subspecies.[3][12]
Habitat and distribution
The rough-legged hawk breeds in
Breeding sites are usually located in areas with plenty of unforested, open ground.
Behaviour
Diet
This species is carnivorous, typically feeding on small mammals, which make up 62–98% of its diet.
This avian predator hunts opportunistically, occasionally supplementing its diet with carrion but focusing primarily on the most locally abundant small vertebrates. Rough-legged hawks will steal prey from other individuals of the same species as well as other species such as the red-tailed hawk, hen harrier (Circus cyaenus), American kestrel (Falco sparverius) and common raven (Corvus corax).[27] Prey sizes typically range from 6.5–2,587 g (0.23–91.25 oz) and adults require 80–120 g (2.8–4.2 oz) of food daily, around the body mass of the largest species of vole or lemming although most species weigh a bit less.[12] These raptors hunt during the daytime.[12] Like most Buteos, rough-legged hawks have been reported both still-hunting (watching for prey from a perch and then stooping) and watching for prey while in flight. Unlike most other large raptors, they may engage in hovering flight above the ground while searching for prey.[3]
Reproduction
Sexual maturity is reached at about two years old. Breeding generally occurs during May but is variable depending upon dates of arrival at breeding grounds. The rough-legged hawk is thought to be monogamous, mating with a single individual for multiple years.[3] No evidence currently suggest otherwise.
Rough-legged buzzards look for suitable nesting territory not in spring, like most migratory birds, but in advance - in autumn. After the breeding season, they make long-distance prospecting flights, look for a suitable habitat with high rodent numbers, and return to that place the following year.[28]
Nests are built soon after arrival to breeding grounds and require 3–4 weeks to complete. Twigs,
Rough-legged hawks could nest in association with peregrine falcons (Falco peregrinus). Peregrines chasing away small rodent predators from their nesting territory and rough-legged hawks could use these hot spots as a nesting territory.[29]
Longevity and mortality
Rough-legged hawks that survive to adulthood can live to an age of 19 years in the wild. One female being kept in an Idaho zoo is over 25 years of age and there is a female that is a minimum of 38 years old living in Redding, CA as of 2015[update].[citation needed] However, perhaps a majority of individuals in the wild do not survive past their first two years of life. The threats faced by young rough-legs can include starvation when prey is not numerous, freezing when Northern climes are particularly harsh during brooding, destruction by humans, and predation by various animals. The chances of survival increase incrementally both when they reach the fledging stage and when they can start hunting for themselves. Death of flying immatures and adults are often the result of human activity, including collisions with power lines, buildings, and vehicles, incidental ingestion of poison or lead from prey or illegal hunting and trapping.[30]
Most predation recorded on this species is on the young at the nest.
Besides predation, it could be other reasons for nestling mortality among rough-legged buzzards. Nestlings in their first two weeks have a lousy temperature regulation. In the tundra landscape, they nest on the ground and during hot weather, they could go out of the nest seeking shelter from the sun. If weather then rapidly changes to the thunderstorm (which is common in the Arctic) nestlings could die without parent protection in a short time in 3–5 m from the nest.[34] Other reasons for nestling mortality are earth-slides of the river-banks, where rough-legged buzzards often build their nests, and chilling.[35]
Vocalization
Adult rough-legged hawks will vocalize alarm calls when intruders approach a nesting site. It is described as a downward slurring whistle, sounding like kiu wiyuk or a lengthy descending kee-eer similar to that of the red-tailed hawk. This cry is given in flight or from a perch every 15–30 seconds. During courtship, both sexes have been recorded to give a whistling sound that changes to a hiss. Following copulation, females will give a cluck-like sound and males vocalize a whistling noise. Fledglings will give begging calls while waiting for parents to provide food.[3]
References
- . Retrieved 19 November 2021.
- ^ Gill F, D Donsker & P Rasmussen (Eds). 2020. IOC World Bird List (v10.2). doi : 10.14344/IOC.ML.10.2.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x Bechard, M.J.; Swem, T.R. (2002). "Rough-legged Hawk (Buteo lagopus)". In Poole, A.; Gill, F. (eds.). The Birds of North America. Philadelphia, PA: The Birds of North America, Inc.
- ^ Richardson, J.; Swainson, W.; Kirby, W. (1831). Fauna Boreali-americana, Or, The Zoology of the Northern Parts of British America: The birds. London: John Murray.
- ^ a b c d "Rough-legged Hawk". Virtual Wildlife. Lethbridge College. Archived from the original on 4 March 2016. Retrieved 18 December 2011.
- ^ "Birds of Prey". Bird of Prey Trail. Archived from the original on 28 October 2012. Retrieved 18 December 2011.
- ISBN 978-0-85661-027-1.
- ISBN 978-0-8493-4258-5.
- ISBN 84-87334-20-2.
- ^ a b Brown, L.; Amadon, D. (1968). Eagles, hawks, and falcons of the world. Vol. 2. New York: McGraw-Hill.
- JSTOR 40166710.
- ^ ISBN 0-7136-8026-1.
- JSTOR 1364791.
- ^ Friedmann, H. (1950). "The birds of Middle and North America". U.S. National Museum Bulletin (50).
- S2CID 198969139. Retrieved 4 June 2011.
- ISBN 978-1-4081-2501-4.
- ^ "Rough-legged Hawk". All About Birds. Cornell Lab of Ornithology. Retrieved 22 August 2012.
- ^ "Hawks – Genus Buteo – Introduction". Oiseaux-birds.com. Retrieved 18 December 2011.
- JSTOR 3675882.
- ^ JSTOR 1366233.
- JSTOR 3677362.
- PMID 25692786.
- S2CID 14623043.
- ^ "Buteo lagopus (Rough-legged buzzard)". Animal Diversity Web.
- ^ Weller, M.W. (1964). "Habitat utilization of two species of buteos wintering in central Iowa" (PDF). Iowa Bird Life. 34: 58–62.
- JSTOR 3565424.
- JSTOR 4088176.
- ISSN 2296-701X.
- ISSN 0004-8038.
- ^ a b Good, G. (2008). "Buteo lagopus". Animal Diversity Web.
- ^ Swem, T.R. (1996). Aspects of the breeding biology of Rough-legged Hawks along the Colville River, Alaska (Master's Thesis). Boise, ID: Boise State University.
- ^ Dement'ev, G.P.; Gladkov, N.A. (1951). Birds of the Soviet Union. Vol. 1. Moscow, USSR: Publishing House Sovetskaya Nauka. [English translation by the Israel Program for Scientific Translations, Jerusalem, Israel, in 1966.]
- ^ White, C.M.; Cade, T.J. (1971). "Cliff-nesting raptors and ravens along the Colville River in arctic Alaska". Living Bird. 10. Cornell Laboratory of Ornithology: 107–150.
- ISSN 1751-8369.
- JSTOR 3546304.
External links
- Rough-legged hawk – Buteo lagopus – USGS Patuxent Bird Identification InfoCenter
- Rough-legged hawk Species Account – Cornell Lab of Ornithology
- Stamps: rough-legged hawk[usurped] at bird-stamps.org[usurped]
- How to ID a rough-legged hawk video
- Rough-legged Hawk video
- "Rough-legged buzzard media". Internet Bird Collection.
- Rough-legged hawk photo gallery at VIREO (Drexel University)