Rough-legged Buzzard
Encyclopedia
The Rough-legged Buzzard (Buteo lagopus), called the Rough-legged Hawk in North America, is a medium-large bird of prey
. It is found in Arctic
and Subarctic
regions of North America
and Eurasia
during the breeding season and migrates south for the winter.
The species exhibits a wide variety of plumage
patterns including light and dark morphs. Nests are typically located on cliffs, bluffs or in trees. Clutch sizes are variable with food availability but 3-5 eggs are usually laid. These hawks hunt over open land, feeding primarily on small mammals. Along with the Kestrels, Kites
and Osprey
, this is one of the few large birds of prey to hover regularly.
and the Red-tailed Hawk
, it is slightly larger, though may be outweighed by the latter.
Compared to the Common Buzzard
, it is longer-winged and more eagle-like
in appearance. 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. Its feet are feathered to the toes (hence its scientific name, lagopus, meaning "hare-footed
") as an adaptation to its arctic home range. Lagopus is derived from Ancient Greek
lago (λαγως), meaning "hare
", and pous (πους), meaning "foot". Its talons are relatively small, reflecting their preferred choice of prey. A broad brown chestband is present in most plumages and a square dark carpal patch contrasting with the white under-wing is an easily identifiable characteristic in light morph individuals.
It is the only hawk of its size to regularly hover over one spot, by beating its wings quickly.
Buteo
, a group of moderately large raptors exhibiting broad wings, short tails and wide robust bodies. This group is known a hawks in North America but referred to as buzzards in Europe.
There are at least 3 recognized subspecies of Buteo lagopus:
and taiga
habitats of North America and Eurasia between the latitudes of 61 and 76° N. Rough-legged Hawks occurring in North America migrate to the central United States for the winter, while Eurasian individuals migrate to southern Europe and Asia. During these winter months, from November to March, preferred habitats include marshes, prairies and agricultural regions where rodent
prey is most abundant.
Breeding sites are usually located in areas with plenty of unforested, open ground. Depending on snow conditions, migrants arrive at breeding grounds during April and May. Home ranges vary with food supply but are commonly reported to be 10-15 square kilometers during the winter, but little is known about home ranges during the breeding season. Although frequently attacked by other bird species such as Gryfalcons and Skuas, the Rough-legged Buzzard is not strongly territorial.
s and voles are the major prey items but this varies with seasonal availability. Some evidence suggests that these hawks may be able to see vole scent marks which are only visible in the ultraviolet
range, allowing them to cue in on prey. The Rough-legged Hawk will also supplement its diet with mice, rats, gerbils, pikas and insects. Ptarmigan
, Lapland Longspur and American Tree Sparrow
are species commonly reported as preferred avian prey. Waterfowl, shorebirds and Short-eared Owl
s are hunted less frequently. When small mammals are scarce, the Rough-legged Hawk will also feed on medium sized mammals including prairie dogs, ground squirrels, muskrats and weasels. During winter, shrub-steppe habitats seem to encourage a strong dependance on rabbit prey.
This avian predator hunts opportunistically, feeding occasionally on carrion
, but focusing primarily on most available food types. Rough-legged Hawks will steal prey from other individuals of the same species as well as other species such as the Red-tailed Hawk
, Northern Harrier, American Kestrel
and Raven
. Prey sizes range from 6.5-2,587 g and adults require 80-120 g of food daily. Individuals hunt during the day time, often hovering above the ground in search of prey.
Nests are built soon after arrival to breeding grounds and require 3–4 weeks to complete. Twigs, sedges and old feathers are used as building materials. Nests are 60–90 cm in diameter and 25–60 cm in height. Cliff ledges and rocky outcroppings are preffered nesting sites. Females can lay 2-7 eggs but will typically lay 3-5. Average egg size is 56.4 mm in length by 44.7 mm in width. Minimum incubation period is 31 days, provided almost exclusively by the female. The male feeds the female during this incubation period. After hatching, young require 4–6 weeks before fledging the nest. Fledglings depend on parents to provide food for 2–4 weeks after leaving the nest.
. This cry is given in flight or from a perch every 15-30 s. During courtship, both sexes have been recorded to give a whistling sound that changes to a hiss. Following copulation, females will give a clucklike sound and males vocalize a whistling noise. Fledglings will give begging calls while waiting for parents to provide food.
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
. It is found in Arctic
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...
and Subarctic
Subarctic
The Subarctic is a region in the Northern Hemisphere immediately south of the true Arctic and covering much of Alaska, Canada, the north of Scandinavia, Siberia, and northern Mongolia...
regions of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
during the breeding season and migrates south for the winter.
The species exhibits a wide variety of plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
patterns including light and dark morphs. Nests are typically located on cliffs, bluffs or in trees. Clutch sizes are variable with food availability but 3-5 eggs are usually laid. These hawks hunt over open land, feeding primarily on small mammals. Along with the Kestrels, Kites
Kite (bird)
Kites are raptors with long wings and weak legs which spend a great deal of time soaring. Most feed mainly on carrion but some take various amounts of live prey.They are birds of prey which, along with hawks and eagles, are from the family Accipitridae....
and Osprey
Osprey
The Osprey , sometimes known as the sea hawk or fish eagle, is a diurnal, fish-eating bird of prey. It is a large raptor, reaching more than in length and across the wings...
, this is one of the few large birds of prey to hover regularly.
Description
This fairly large raptorial species is 48–60 cm (18.9–23.6 in) with an average wingspan of 120–150 cm (47.2–59.1 in). Individuals can weigh from 600 to 1800 g (1.3 to 4 lb) with females typically being larger and heavier than males. The plumage is predominantly brown in colour and often shows a high degree of speckling. A wide variety of plumage patterns are exhibited in light vs. dark morphs, males vs. females and adults vs. juveniles. Extensive field experience is required to distinguish between certain plumage variations. Compared to its more common cousins, the Common BuzzardCommon Buzzard
The Common Buzzard is a medium to large bird of prey, whose range covers most of Europe and extends into Asia. It is usually resident all year, except in the coldest parts of its range, and in the case of one subspecies.-Description:...
and the Red-tailed Hawk
Red-tailed Hawk
The Red-tailed Hawk is a bird of prey, one of three species colloquially known in the United States as the "chickenhawk," though it rarely preys on standard sized chickens. It breeds throughout most of North America, from western Alaska and northern Canada to as far south as Panama and the West...
, it is slightly larger, though may be outweighed by the latter.
Compared to the Common Buzzard
Common Buzzard
The Common Buzzard is a medium to large bird of prey, whose range covers most of Europe and extends into Asia. It is usually resident all year, except in the coldest parts of its range, and in the case of one subspecies.-Description:...
, it is longer-winged and more eagle-like
Eagle
Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...
in appearance. 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. Its feet are feathered to the toes (hence its scientific name, lagopus, meaning "hare-footed
Hare
Hares and jackrabbits are leporids belonging to the genus Lepus. Hares less than one year old are called leverets. Four species commonly known as types of hare are classified outside of Lepus: the hispid hare , and three species known as red rock hares .Hares are very fast-moving...
") as an adaptation to its arctic home range. Lagopus is derived from Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
lago (λαγως), meaning "hare
Hare
Hares and jackrabbits are leporids belonging to the genus Lepus. Hares less than one year old are called leverets. Four species commonly known as types of hare are classified outside of Lepus: the hispid hare , and three species known as red rock hares .Hares are very fast-moving...
", and pous (πους), meaning "foot". Its talons are relatively small, reflecting their preferred choice of prey. A broad brown chestband is present in most plumages and a square dark carpal patch contrasting with the white under-wing is an easily identifiable characteristic in light morph individuals.
It is the only hawk of its size to regularly hover over one spot, by beating its wings quickly.
Taxonomy
The Rough-legged Hawk is a member of the genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Buteo
Buteo
Buteo is a genus of medium to fairly large, wide-ranging raptors with a robust body and broad wings. In the Old World, members of this genus are called "buzzards", but "hawk" is used in North America...
, a group of moderately large raptors exhibiting broad wings, short tails and wide robust bodies. This group is known a hawks in North America but referred to as buzzards in Europe.
There are at least 3 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 homogenous brown colour, contrasting well with the paler head.
- B. l. sanctijohannis breeds in North America. It has pale, speckled dorsal plumage and is slightly smaller than B. l. lagopus.
- B. l. kamtchatkensis breeds from north Siberia to Pacific North America. It has paler plumage when compared with B. l. sanctijohannis.
Habitat and Distribution
The Rough-legged Hawk breeds in tundraTundra
In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...
and taiga
Taiga
Taiga , also known as the boreal forest, is a biome characterized by coniferous forests.Taiga is the world's largest terrestrial biome. In North America it covers most of inland Canada and Alaska as well as parts of the extreme northern continental United States and is known as the Northwoods...
habitats of North America and Eurasia between the latitudes of 61 and 76° N. Rough-legged Hawks occurring in North America migrate to the central United States for the winter, while Eurasian individuals migrate to southern Europe and Asia. During these winter months, from November to March, preferred habitats include marshes, prairies and agricultural regions where rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
prey is most abundant.
Breeding sites are usually located in areas with plenty of unforested, open ground. Depending on snow conditions, migrants arrive at breeding grounds during April and May. Home ranges vary with food supply but are commonly reported to be 10-15 square kilometers during the winter, but little is known about home ranges during the breeding season. Although frequently attacked by other bird species such as Gryfalcons and Skuas, the Rough-legged Buzzard is not strongly territorial.
Diet
This species is carnivorous, typically feeding on small mammals, which make up 62-98% of its diet. LemmingLemming
Lemmings are small rodents, usually found in or near the Arctic, in tundra biomes. They are subniveal animals, and together with voles and muskrats, they make up the subfamily Arvicolinae , which forms part of the largest mammal radiation by far, the superfamily Muroidea, which also includes rats,...
s and voles are the major prey items but this varies with seasonal availability. Some evidence suggests that these hawks may be able to see vole scent marks which are only visible in the ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
range, allowing them to cue in on prey. The Rough-legged Hawk will also supplement its diet with mice, rats, gerbils, pikas and insects. Ptarmigan
Ptarmigan
The Rock Ptarmigan is a medium-sized gamebird in the grouse family. It is known simply as Ptarmigan in Europe and colloquially as Snow Chicken or Partridge in North America, where it is the official bird for the territory of Nunavut, Canada, and the official game bird for the province of...
, Lapland Longspur and American Tree Sparrow
American Tree Sparrow
The American Tree Sparrow , formerly known as the Winter Sparrow, is a medium-sized sparrow.Adults have a rusty cap and grey underparts with a small dark spot on the breast. They have a rusty back with lighter stripes, brown wings with white bars and a slim tail. Their face is grey with a rusty...
are species commonly reported as preferred avian prey. Waterfowl, shorebirds and Short-eared Owl
Short-eared Owl
The Short-eared Owl is a species of typical owl . In Scotland this species of owl is often referred to as a cataface, grass owl or short-horned hootlet. Owls belonging to genus Asio are known as the eared owls, as they have tufts of feathers resembling mammalian ears. These "ear" tufts may or may...
s are hunted less frequently. When small mammals are scarce, the Rough-legged Hawk will also feed on medium sized mammals including prairie dogs, ground squirrels, muskrats and weasels. During winter, shrub-steppe habitats seem to encourage a strong dependance on rabbit prey.
This avian predator hunts opportunistically, feeding occasionally on carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...
, but focusing primarily on most available food types. Rough-legged Hawks will steal prey from other individuals of the same species as well as other species such as the Red-tailed Hawk
Red-tailed Hawk
The Red-tailed Hawk is a bird of prey, one of three species colloquially known in the United States as the "chickenhawk," though it rarely preys on standard sized chickens. It breeds throughout most of North America, from western Alaska and northern Canada to as far south as Panama and the West...
, Northern Harrier, American Kestrel
American Kestrel
The American Kestrel , sometimes colloquially known as the Sparrow Hawk, is a small falcon, and the only kestrel found in the Americas. It is the most common falcon in North America, and is found in a wide variety of habitats. At long, it is also the smallest falcon in North America...
and Raven
Raven
Raven is the common name given to several larger-bodied members of the genus Corvus—but in Europe and North America the Common Raven is normally implied...
. Prey sizes range from 6.5-2,587 g and adults require 80-120 g of food daily. Individuals hunt during the day time, often hovering above the ground in search of prey.
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. No evidence currently suggest otherwise.Nests are built soon after arrival to breeding grounds and require 3–4 weeks to complete. Twigs, sedges and old feathers are used as building materials. Nests are 60–90 cm in diameter and 25–60 cm in height. Cliff ledges and rocky outcroppings are preffered nesting sites. Females can lay 2-7 eggs but will typically lay 3-5. Average egg size is 56.4 mm in length by 44.7 mm in width. Minimum incubation period is 31 days, provided almost exclusively by the female. The male feeds the female during this incubation period. After hatching, young require 4–6 weeks before fledging the nest. Fledglings depend on parents to provide food for 2–4 weeks after leaving the nest.
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 HawkRed-tailed Hawk
The Red-tailed Hawk is a bird of prey, one of three species colloquially known in the United States as the "chickenhawk," though it rarely preys on standard sized chickens. It breeds throughout most of North America, from western Alaska and northern Canada to as far south as Panama and the West...
. This cry is given in flight or from a perch every 15-30 s. During courtship, both sexes have been recorded to give a whistling sound that changes to a hiss. Following copulation, females will give a clucklike sound and males vocalize a whistling noise. Fledglings will give begging calls while waiting for parents to provide food.
External links
- Rough-legged Hawk Buteo lagopus - USGS Patuxent Bird Identification InfoCenter
- Rough-legged Hawk - Cornell Lab of Ornithology
- Picture Link: Rough-Legged Hawk in Westmoreland, NH
- Rough-legged Hawk Information and Photos - South Dakota Birds and Birding
- Stamps: Rough-legged Hawk
- How to ID a Rough-legged Hawk video
- Buzzard video