Overview

Brief Summary

Buteo lineatus

A relatively large (17-24 inches) hawk, the Red-shouldered Hawk takes its name from the large rust-colored shoulder patches visible from above or while perching. This species may also be identified by its brown back, barred white-and-black wings, and broad black tail banded with white. A pale form, with washed-out plumage on the chest, back, and head, occurs in south Florida. Like most species of raptors, females are larger than males. The Red-shouldered Hawk primarily breeds in the eastern United States and southeastern Canada, withdrawing from northern portions of its range and expanding south into northern Mexico in winter. Unusually for a North American hawk, the Red-shouldered Hawk has another population, separated from the main population by thousands of miles, that is a permanent resident along the Pacific coast of California. Eastern Red-Shouldered Hawks inhabit mature forests with deciduous or mixed deciduous and evergreen trees. Western populations also inhabit these habitat types, but are also likely to be found in human-altered environments near woods. Red-shouldered Hawks primarily eat small vertebrates, including small mammals, amphibians, and occasionally small songbirds and doves. Red-shouldered Hawks may be most easily observed while hunting, when they drop down from high perches to capture terrestrial prey with their talons. This species may also be observed perching, although this hawk’s coloration and the dense vegetation of its preferred habitat help to provide camouflage. Red-shouldered Hawks are most active during the day.

Threat Status: Least concern

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Distribution

Geographic Range

Red-shouldered hawks are found in the Nearctic region. They breed throughout the eastern and northeast United States into southern Canada, and west of the Sierra Nevada in California. Populations of red-shouldered hawks in the eastern U.S. and California are resident. Populations that breed in the northeast U.S. and southern Canada migrate to northern Mexico for the winter.

Biogeographic Regions: nearctic (Native )

  • Christopher, R. 1990. Book of North American Birds. Pleasantville: Reader's Digest.
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Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDING: northern California south, west of the Sierran Divide, to northern Baja California; and from eastern Nebraska, Iowa, central Minnesota, northern Wisconsin, northern Michigan, southern Ontario, southwestern Quebec and southern New Brunswick south to Veracruz, Tamaulipas, central and southern Texas, the Gulf Coast, and Florida (to the Florida Keys); also locally in the valley of Mexico (recorded in Zacatecas and Distrito Federal) (AOU 1983, Crocoll 1994). Now very scarce as a breeder in eastern and central Mexico. NON-BREEDING: California and throughout the breeding range, at least sporadically, in eastern North America, but primarily from eastern Kansas, central Missouri, the Ohio Valley, northwestern Pennsylvania, southern New York, and southern New England south to central Mexico (Crocoll 1994, AOU 1998). Most numerous in the Gulf coast states and Georgia (Root 1988).

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occurs (regularly, as a native taxon) in multiple nations

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National Distribution

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

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Geographic Range

Red-shouldered hawks are found in the Nearctic region. They breed throughout the eastern and northeast United States into southern Canada, and west of the Sierra Nevada in California. Populations of red-shouldered hawks in the eastern U.S. and California are resident. Populations that breed in the northeast U.S. and southern Canada migrate to northern Mexico for the winter.

Biogeographic Regions: nearctic (Native )

  • Christopher, R. 1990. Book of North American Birds. Pleasantville: Reader's Digest.
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Physical Description

Morphology

Physical Description

Red-shouldered hawks are large, broad-winged hawks with a long tails and heavy bodies. Female red-shouldered hawks are larger than males. Female red-shouldered hawks average 700 g and 48 to 61 cm in length whereas males average 550 g and 43 to 58 cm in length. Adults have a wingspan of 92 to 107 cm (average 100 cm). Adult red-shouldered hawks have a brown head, a dark brown back and reddish underparts with dark brown streaks. Juveniles look similar to adults, but have creamy underparts with dark brown spots and streaks. Both adults and juveniles have reddish upper wing coverts (feathers), which make them look like they have red shoulders. They also have dark brown tails with white bands.

There are five subspecies red-shouldered hawks (Buteo lineatus).

Range mass: 550 to 700 g.

Range length: 43 to 61 cm.

Range wingspan: 92 to 107 cm.

Average wingspan: 100 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry ; polymorphic

Sexual Dimorphism: female larger

Average basal metabolic rate: 2.11 W.

  • Whetmore, A. 1965. Water, Prey, and Game Birds of North America. Chicago: National Geographic Society.
  • Clark, W., B. Wheeler. 2001. A field guide to hawks of North America, 2nd Edition. New York: Houghton Miflin Company.
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Physical Description

Red-shouldered hawks are large, broad-winged hawks with a relatively long tails and heavy bodies. They show reverse sexual size dimorphism, meaning that females are larger than males. Female red-shouldered hawks average 700 g and 48 to 61 cm in length whereas males average 550 g and 43 to 58 cm in length. Adults have a wingspan of 92 to 107 cm (average 100 cm). Adult red-shouldered hawks have a brown head, a dark brown back and reddish underparts with dark brown streaks. Juveniles appear similar to adults, but have creamy underparts with dark brown spots and streaks. Both adults and juveniles have reddish lesser secondary upper wing coverts, which give the impression of red shoulders, giving this species its name. The tail of the both immature and mature red-shouldered hawks is dark brown with white bands.

Five subspecies of Buteo lineatus are recognized. These subspecies are separated based on geography and physical characteristics. The head and breast markings of the Florida subspecies, Buteo lineatus extimus and Buteo lineatus alleni, are slightly paler than other Red-shouldered hawks. The California subspecies, Buteo lineatus elegans, and the Texas subspecies, Buteo lineatus texanus, however, have vibrant, deep red markings on the lesser secondary upperwing coverts, underwing coverts and breast.

Range mass: 550 to 700 g.

Range length: 43 to 61 cm.

Range wingspan: 92 to 107 cm.

Average wingspan: 100 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry ; polymorphic

Sexual Dimorphism: female larger

Average basal metabolic rate: 2.11 W.

  • Whetmore, A. 1965. Water, Prey, and Game Birds of North America. Chicago: National Geographic Society.
  • Clark, W., B. Wheeler. 2001. A field guide to hawks of North America, 2nd Edition. New York: Houghton Miflin Company.
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Size

Length: 48 cm

Weight: 643 grams

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Ecology

Habitat

Comments: BREEDING: varies from bottomland hardwoods and riparian areas (Stewart 1949, Henny et al. 1973, Bednarz and Dinsmore 1981, Kimmel and Fredrickson 1981, Woodrey 1986, Preston et al. 1989) to upland deciduous or mixed deciduous-conifer forest (Titus and Mosher 1981, Armstrong and Euler 1983, Morris and Lemon 1983, Crocoll and Parker 1989). Nesting areas are almost always found near some form of water, such as a swamp, marsh, river, or pond (Preston et al. 1989, Bosakowski et al. 1992), and the habitat is usually well forested (Portnoy and Dodge 1979, Kimmel and Fredrickson 1981, Titus and Mosher 1981, Morris and Lemon 1983, Ebbers 1989). Further, nesting habitat typically is mature forest with a well-developed high canopy and variable amounts of understory vegetation (Postupalsky 1980, Titus and Mosher 1981, Armstrong and Euler 1983, Morris and Lemon 1983, Titus 1984, Preston et al. 1989.). Sometimes occurs in coniferous stands in the West. In California, has been expanding range of occupied habitats to include various woodlands, including stands of eucalyptus trees amid urban sprawl (Ehrlich et al. 1992).

The nest is usually built in the main crotch of a large, living tree in mature forest, although in Florida, palmettos may be used. In eastern North America, nests generally are far from forest edges. At least 43 species of mainly deciduous trees have been chosen, so that the size and shape seem more important than the actual species (Bednarz 1979, Apfelbaum and Seelbach 1983, Titus and Mosher 1987, Palmer 1988, Ebbers 1989). The bulky structure of twigs, rather flat on top, is typically placed approximately halfway up the tree in the lower portion of the canopy (Morris et al. 1982, Titus and Mosher 1987). The typical height is between 11-15 m but can range from 1.5-33.5 m (Peck and James 1983, Ebbers 1989). The nest is lined with stems, leaves, lichen, and bark. Active nests are decorated with greenery and other materials. Hemlock and other conifer sprigs are often mentioned as nest greenery, as are deciduous sprigs once they have leafed out, and Bent (1937) mentioned such plants as flowering violets and nightshade. Other materials have included cornstalks, ears, and husks, dried tent caterpillar webs, tissue paper, twine, and nests of eastern wood-pewee, red-eyed vireo, and northern oriole (Palmer 1988).

In eastern North America, may use nest used previously by barred owl (STRIX VARIA) (and vice versa) (Palmer 1988). See Dijak et al. (1990) for information on nest-site characteristics affecting success and reuse of nests in Missouri.

NON-BREEDING: less restricted than that used for breeding; favors lowland areas near water, either standing or running, including river valleys, swamps, marshes, and perhaps canyon bottoms (Palmer 1988), and level, open country with scattered large trees (Bent 1937). In Florida, Bohall and Collopy (1984) found hawks most often in open areas such as pastures and fallow fields.

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Habitat and Ecology

Systems
  • Terrestrial
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Red-shouldered hawks live in forests and swamps. They build their nests 6 to 15 meters (20 to 60 feet) above the ground in the branches of hardwood trees in wet woodland areas. They prefer to have dead trees nearby, where they can perch and see the forest floor.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: forest

Wetlands: swamp

  • Callahan, P. 1974. The Magnificent Birds of Prey. New York: Holiday House.
  • Woodward, C., A. Howell, N. Mayo. 1931. Florida Birds. Tampa: Florida Grower Press.
  • Crocoll, S. 1994. Red-shouldered hawk (Buteo lineatus). Pp. 1-20 in A Poole, F Gill, eds. The Birds of North America, Vol. 107. Washington, DC: The American Ornithologist's Union.
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Red-shouldered hawks usually inhabit mature deciduous or mixed deciduous-conifer forests and swamps. They build their nests 6 to 15 meters (20 to 60 feet) above the ground in the branches of deciduous trees in wet woodland areas. They prefer to have dead trees nearby, where they can perch and enjoy an unobstructed view of the forest floor.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: forest

Wetlands: swamp

  • Callahan, P. 1974. The Magnificent Birds of Prey. New York: Holiday House.
  • Woodward, C., A. Howell, N. Mayo. 1931. Florida Birds. Tampa: Florida Grower Press.
  • Crocoll, S. 1994. Red-shouldered hawk (Buteo lineatus). Pp. 1-20 in A Poole, F Gill, eds. The Birds of North America, Vol. 107. Washington, DC: The American Ornithologist's Union.
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Migration

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

North of a line roughly from southern Minnesota to the southern border of Ohio, to central New Hampshire, most red-shouldered hawks are resident only during the breeding season, though a few may overwinter in the region. The migratory tendency is expressed most strongly in the Northeast population, although there are also flights in the Midwest and Southeast, and a light fall movement in California. From the latitude of about Virginia southward, populations are mainly resident.

In Maryland, montane populations are migratory whereas those in the Piedmont and coastal areas are not.

Spring migration is early; birds move by 15 February in Maryland and the District of Columbia (Palmer 1988). Overall, the northward movement peaks in March. Migrants begin to arrive in Massachusetts in mid-March, in southwestern Quebec from March to mid-April. In Michigan, migrating birds arrive at nesting grounds between late February and early April.

Fall migration begins in early September in the Northeast, extending into November and even late December for a few tardy individuals. Dates are similar across the northern part of the range.

Typically avoids crossing large bodies of water (Palmer 1988).

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Trophic Strategy

Comments: Diet varies regionally and seasonally, sometimes annually depending on availability. Common prey items include snakes of moderate size; amphibians up to bullfrog size; mammals mostly from shrew to chipmunk size; small lizards and young turtles; relatively few birds to grackle size; a few small fishes; a few crayfishes; insects in considerable numbers, usually of cricket and large grasshopper size; and miscellaneous invertebrates such as centipedes, earthworms, and snails (Palmer 1988). In northeastern North America, juvenile chipmunks are important prey during the hawk nestling period (Portnoy and Dodge 1979, Morris 1980, Johnson 1989, In Iowa, Bednarz and Dinsmore (1985) Iowa observed that the proportion of prey types changed dramatically between years, with mammals dominating one year and amphibians and arthropods the next year. Apparently the change in prey type had no effect on productivity between the two years.

Hunts beneath forest canopy and in more open nearby terrain that is preferably moist or near water; hunts from perch or flies low and attacks prey from close range (Palmer 1988). In Iowa, hunted in small clearings averaging a few hectares (see Bushman and Therres 1988).

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Food Habits

Red-shouldered hawks eat small mammals as big as rabbits and Sciuridae. They also eat reptiles, such as serpents and Sauria, and amphibians, including Anura. They also eat small birds and large insects. Astacidae cambaru are an important food for red-shouldered hawks in some regions.

Red-shouldered hawks search for prey by perching on top of a tall tree or soaring over woodlands. When they sight prey, they kill it by dropping down onto it from the air. They may store food near their nest to eat later. There is no information available about how red-shouldered hawks drink water.

Red-shouldered hawks use sight and hearing to hunt successfully. They do not hunt by smell. Red-shouldered hawks have very sharp eyesight and broad wings which allow them to be very successful hunters.

There is no information available about how red-shouldered hawks obtain water.

Animal Foods: birds; mammals; amphibians; reptiles; insects; aquatic crustaceans

Foraging Behavior: stores or caches food

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Food Habits

The diet of red-shouldered hawks consists primarily of small mammals, the largest of these being rabbits and squirrels. Other food items include reptiles and amphibians, such as snakes, toads, frogs and lizards, small birds and large insects. Crayfish are important prey for red-shouldered hawks in some regions.

Red-shouldered hawks search for prey while perched on a treetop or soaring over woodlands. When they sight prey, they kill it by dropping directly onto it from the air. They may cache food near their nest for later consumption.

Red-shouldered hawks use sight and hearing to hunt successfully. They do not hunt by smell. Some key characteristics that make red-shouldered hawks especially well-adapted to hunting are sharp eyesight and broad wings. The shape and structure of red-shouldered hawks’ wings allow them to soar effortlessly for extended periods of time searching for prey. The hawks’ large eyes are situated to look forward. Although this means that the birds must turn their heads in order to keep prey in view, the orientation of their eyes affords them excellent depth perception. The high concentrations of light-sensitive cone cells in red-shouldered hawks’ eyes also provide good resolving power and very sharp vision.

Animal Foods: birds; mammals; amphibians; reptiles; insects; aquatic crustaceans

Foraging Behavior: stores or caches food

Primary Diet: carnivore (Eats terrestrial vertebrates)

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Associations

Ecosystem Roles

Red-shouldered hawks compete with other large birds, including Aquila chrysaetos, Falco mixicanus, Buteo jamaicensis, Strix varia and Bubo virginianus for territories. They provide food for their predators; primarily Bubo virginianus and Procyon lotor. They also host at least one blood parasite (Leucocytozoa) and several external parasites.

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Predation

Incubating red-shouldered hawk adults, nestlings and eggs are vulnerable to predation by Bubo virginianus and Procyon lotor. Non-incubating adults are not usually vulnerable to predation.

Known Predators:

  • raccoons (Procyon_lotor)
  • great horned owls (Bubo_virginianus)

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Ecosystem Roles

Red-shouldered hawks compete with other large birds, including golden eagles, prairie falcons, red-tailed hawks, barred owls and great-horned owls for territories. They provide food for their predators; primarily great horned owls and raccoons. They also host at least one blood parasite (Leucocytozoa) and several external parasites.

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Predation

Incubating red-shouldered hawk adults, nestlings and eggs are vulnerable to predation by great-horned owls and raccoons. Non-incubating adults are not usually vulnerable to predation.

Known Predators:

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Known prey organisms

Buteo lineatus preys on:
Insecta
Amphibia
Reptilia
Mammalia

This list may not be complete but is based on published studies.
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Population Biology

Number of Occurrences

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: Eleven states or provinces report more than 100 EOs. In the early 1990s, ranked S4 or S5 in at least 15 states/provinces.

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Global Abundance

10,000 - 100,000 individuals

Comments: Rangewide numbers not available. According to Risley (1983 COSEWIC report), probably there were at least 468 breeding pairs in Canada as of the early 1980s. Kirk et al. (1995) reported the estimated number of breeding pairs in Canada as 2000-5000.

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General Ecology

Mortality has been reported to occur during the incubation, nestling, and fledgling stages of the breeding season (Craighead and Craighead 1956, Janik and Mosher 1982, Bosakowski and Speiser 1986, Crocoll and Parker 1989). Adults and juveniles have also been reported to suffer mortality (McCrary and Bloom 1984, Crocoll and Parker 1989). Mortality has taken the form of wind-destroyed nests (Wiley 1975, Portnoy and Dodge 1979, Dijak et al. 1990), addled eggs (Janik and Mosher 1982, Crocoll and Parker 1989), starvation of nestlings (Crocoll and Parker 1989), human disturbance at or near the nest-site (Craighead and Craighead 1956, Wiley 1975), and predation of eggs, nestlings or adults (Craighead and Craighead 1956, Wiley 1975, Portnoy and Dodge 1979, Bosakowski and Speiser 1986, Crocoll and Parker 1989). The most frequent predators on eggs and young are raccoons (PROCYON LOTOR) and great horned owls (BUBO VIRGINIANUS).

Breeding density is highly variable; recorded values include one pair per 48.7 ha in central Maryland (Stewart 1949), one pair per 171 ha in western New York (Crocoll and Parker 1989), one pair per 417 ha in Massachusetts, one pair per 455-588 ha in Indiana, one pair per 645 ha in Michigan (Craighead and Craighead 1956), and 1 pair/1000 ha in Wisconsin (see Peterson and Crocoll 1992). Stewart (1949) found nests a mean distance of 1072 m apart in the wide upper Patuxent River drainage in Maryland, and Parker (1986) found similar internest distances in Missouri. Crocoll and Parker (1989) found nests a mean distance of 1271 m apart in the Canadaway Creek Wildlife Management Area of western New York. Adjacent nests were 0.37-1.27 km apart in creek bottoms in southern California. Breeding home range of radio-tagged birds in California averaged 62 ha for males, 37 ha for females; used less space when not breeding. In northern New Jersey, nesting density was 0.22 nests per 100 ha, the highest density yet reported (about twice that reported in the few comparable studies in other states) (Bosakowski et al. 1992).

Often uses nests of previous years (Terres 1980). Nesting territories can be used for many years by a succession of pairs, even in the face of logging and (formerly) egg collecting. Bent (1937) reported an unbroken record of 26 years for a territory that was occupied for at least 42 years, until the woods were nearly ruined by cutting. His longest record was 47 years, but he knew of a tract that was occupied for over a half-century, from 1872 until 1923.

LEUCOCYTOZOA sp., a hematozoan, was detected in the blood of hawks tested in Oklahoma (Kocan et al. 1977). Two lice (COLPOCEPHALUM FLAVESCENS and PHILOPTERUS TAUROCEPHALUS) and one bird fly (LYNCHIA AMERICANA) have been found on red-shoulders (Peters 1936). In New York, the ears of nestlings commonly were full of maggots (PROTOCALLIPHORA SPLENDIDA) (Sargent 1938). These maggot infestations seemingly did not cause deafness or hinder survival (Hands et al. 1989).

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Life History and Behavior

Behavior

Communication and Perception

Red-shouldered hawks use physical displays, such as courtship flights, and vocalizations to communicate. Biologists recognize seven different calls given by red-shouldered hawk adults. The most common call is "kee-aah". This call is used to announce that a territory is occupied, and when the birds are alarmed.

Communication Channels: visual ; acoustic

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Communication and Perception

Red-shouldered hawks use physical displays, such as courtship flights, and vocalizations to communicate. Biologists recognize seven different calls given by red-shouldered hawk adults. The most common call is "kee-aah". This call is used to announce that a territory is occupied, and when the birds are alarmed.

Communication Channels: visual ; acoustic

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Life Expectancy

Lifespan/Longevity

Wild red-shouldered hawks live an average of 25.6 months. The oldest known red-shouldered hawk lived 19 years and 11 months.

Range lifespan

Status: wild:
20 (high) years.

Average lifespan

Status: wild:
25.6 months.

Average lifespan

Status: wild:
239 months.

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Lifespan/Longevity

Wild red-shouldered hawks live an average of 25.6 months. The oldest known red-shouldered hawk lived 19 years and 11 months.

Range lifespan

Status: wild:
20 (high) years.

Average lifespan

Status: wild:
25.6 months.

Average lifespan

Status: wild:
239 months.

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Lifespan, longevity, and ageing

Maximum longevity: 20 years (wild) Observations: One animal was caught and released at age 20 (John Terres 1980).
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Reproduction

Courtship, territory establishment, and nest building (or refurbishing) occur shortly after arrival on the breeding grounds. In New York, Crocoll and Parker (1989) recorded birds back on territories and relining nests during the second and third weeks of March. Portnoy and Dodge (1979) in Massachusetts observed courtship flights during March and nest relining during the last week of March and first week of April. Morris et al. (1982) in southwestern Quebec observed territorial hawks soaring from early March to mid-April. Farther south, nesting activities begin several weeks earlier. Records from Alabama, Louisiana, and Oklahoma indicate that breeding begins in February.

Aerial nuptial displays are impressive and include "high-circling" and "sky-dancing," both extremely vocal performances. In the sky-dance, one individual (presumably the male) rides an upward thermal, crying as it circles, then drops with folded wings into a steep dive, pulling up and then shooting upward again. Neighboring pairs often join in, with as many as ten birds involved. The sky-dance can be immediately followed by copulation, which "occurs repeatedly and over considerable time" (Palmer 1988).

Clutch size varies from one to six (Palmer 1988), with two to four eggs being the most common sizes throughout the range. Clutch size is commonly two in Florida, three to four in the northern U.S. A mean of 3.45 eggs from 42 clutches was reported for the Great Lakes States (Henny 1972). Eggs are laid January-June (mostly March-April) in the southeastern U.S., March-June (mostly April) in northern U.S., mostly March-April in California (Palmer 1988). Nests late March to late May in Maryland (Bushman and Therres 1988) and New York (Bull 1974).

Incubation is by both sexes, but mainly by the female, who is fed by the male, and commences with the laying of the first egg. The incubation period is around 33 days per egg (Newton 1979), and the young hatch asynchronously and thus vary in size, as with many raptors (Newton 1979). The semi-altricial young are inactive at first, becoming active at about 10 days. Feathering begins in about two weeks. The nestling period lasts from five to six weeks (Harrison 1978, Crocoll and Parker 1989). Young leave the nest at 5-6 weeks; in California, first flight occurs at about 45 days (sometimes at considerably older age). Fledging generally occurs in mid-June in Maryland (Janik and Mosher 1982), June to mid-July in New York (Bull 1974, Crocoll and Parker 1989), and late June-early July in Massachusetts (Portnoy and Dodge 1979). Dates are similar throughout the northern range of the species, and are advanced 4 to 8 weeks in the south. In southern California, parents supplied food to young for 8-10 weeks after fledging.

Although a few nest at one year of age (Apanius 1977), most first breed when at least two years old (Palmer 1988). There has been evidence of polyandry with copulation and trio bonding at the nest recorded (Palmer 1988).

Nesting success (measured as the percentage of nests that fledge at least one young) has been reported to vary from 52.9% in Maryland to 100% in Missouri with an average of 68.7% over nine North American studies (Crocoll and Parker 1989). Two one-year studies reported lower nest success rates: 47.4% for 19 nests in northern Lower Michigan in 1986 (Ebbers 1986), and 25% for 1966 at the Patuxent Wildlife Research Center, Maryland (Henny et al. 1973).

The average number of young fledged per nest over the previously cited nine studies varied from 1.11 young to 2.9. Henny et al. (1973) used a mathematical model and field data to predict that in a stable population each pair should fledge an average of 1.95 young. Four of the nine above mentioned studies had fledging numbers below the Henny et al. (1973) standard. Three of the studies were conducted in the Northeast: New York (1.11 young fledged, Crocoll and Parker 1989), Western Maryland (1.8 young fledged, Janik and Mosher 1982), and central Maryland (1.58 young fledged, Henny et al. 1973). One Michigan population produced a mean 1.2 young fledged (n = 44) over three years of study, while another population fledged 2.2 young (n = 29) over the same time period (Ebbers 1989). Ebbers (1989) noted that there is concern that the 1.95 standard may be too high because of possible biases in the data used to scale the model values. Nevertheless, it does appear that some populations produce excess young ("source" populations), while others would not survive without immigration ("sink" populations).

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Red-shouldered hawks are monogamous and territorial. They perform courtship flights by soaring together in broad circles while calling, or soaring and diving toward one another. Males may also perform a "sky-dance" by soaring high in the air, and then making several steep dives. These courtship flights usually occur in late morning and early afternoon.

Mating System: monogamous

Red-shouldered hawks breed once per year between April and July. They often use the same nest for several years, fixing it up each spring. The male and female both build the nest, which is large and deep and made from sticks, twigs, shredded bark, leaves and green sprigs.

The female lays 3 to 4 white eggs with brown or lavender blotches. This takes 2 to 3 days. The eggs are incubated for 33 days. The egg that was laid first hatches first. The nestlings are altricial, meaning that they are helpless and need to be cared for by the parents. The female broods the chicks for at least a week after they hatch. The male brings food to the nest for the female and nestlings during the nestling stage. Chicks begin to leave the nest at 6 weeks old, but are fed by the parents for another 8 to 10 weeks. Chicks become independent of the parents at 17 to 19 weeks old. After becoming independent, they may still roost in or near the nest at night. Red-shouldered hawks begin breeding when they are 1 year old or older.

Breeding interval: Red-shouldered hawks breed once yearly.

Breeding season: Red-shouldered hawks breed between April and July, with peak activity occurring between early April and mid June.

Range eggs per season: 3 to 4.

Average time to hatching: 33 days.

Average fledging age: 6 weeks.

Range time to independence: 17 to 19 weeks.

Range age at sexual or reproductive maturity (female): 1 (low) years.

Range age at sexual or reproductive maturity (male): 1 (low) years.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)

Average time to hatching: 33 days.

Average eggs per season: 3.

Male and female red-shouldered hawks both protect the nest and incubate the eggs. The female broods the chicks during the nestling stage while the male does most of the hunting for the female and the chicks. Both parents feed the young during the nestling and fledgling stages.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female); post-independence association with parents

  • Callahan, P. 1974. The Magnificent Birds of Prey. New York: Holiday House.
  • Crocoll, S. 1994. Red-shouldered hawk (Buteo lineatus). Pp. 1-20 in A Poole, F Gill, eds. The Birds of North America, Vol. 107. Washington, DC: The American Ornithologist's Union.
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Red-shouldered hawks are monogamous and territorial. Courtship displays occur on the breeding grounds, and involve soaring together in broad circles while calling, or soaring and diving toward one another. Males may also perform the "sky-dance" by soaring high in the air, and then making a series of steep dives, each followed by a wide spiral and rapid ascent. These courtship flights usually occur in late morning and early afternoon.

Mating System: monogamous

Red-shouldered hawks breed once per year between April and July, with peak activity occurring between early April and mid June. They often use the same nest from year to year, refurbishing it each spring. Both the male and female build or refurbish the nest, which is large and deep, constructed from sticks, twigs, shredded bark, leaves and green sprigs.

The female lays 3 to 4 white eggs with brown or lavender blotches over the course of 2 to 3 days. Incubation begins when the first or second egg is laid, and lasts for 33 days. Hatching is asynchronous, with up to 7 days between the first and last chick. The nestlings are altricial, and are brooded nearly constantly by the female for at least a week. The male brings food to the nest for the female and nestlings during the nestling stage, which lasts approximately 6 weeks. Chicks begin to leave the nest at 6 weeks, but are fed by the parents for another 8 to 10 weeks. Chicks become independent of the parents at 17 to 19 weeks old. After becoming independent, they may still roost in or near the nest at night. Red-shouldered hawks begin breeding when they are 1 year old or older.

Breeding interval: Red-shouldered hawks breed once yearly.

Breeding season: Red-shouldered hawks breed between April and July, with peak activity occurring between early April and mid June.

Range eggs per season: 3 to 4.

Average time to hatching: 33 days.

Average fledging age: 6 weeks.

Range time to independence: 17 to 19 weeks.

Range age at sexual or reproductive maturity (female): 1 (low) years.

Range age at sexual or reproductive maturity (male): 1 (low) years.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)

Average time to hatching: 33 days.

Average eggs per season: 3.

Male and female red-shouldered hawks both protect the nest and incubate the eggs. The female broods the chicks during the nestling stage while the male does most of the hunting for the female and the chicks. Both parents feed the young during the nestling and fledgling stages.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female); post-independence association with parents

  • Callahan, P. 1974. The Magnificent Birds of Prey. New York: Holiday House.
  • Crocoll, S. 1994. Red-shouldered hawk (Buteo lineatus). Pp. 1-20 in A Poole, F Gill, eds. The Birds of North America, Vol. 107. Washington, DC: The American Ornithologist's Union.
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Molecular Biology and Genetics

Molecular Biology

Barcode data: Buteo lineatus

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There are 3 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

NNNNNNNNNNNNNNNNNNNNNNNNNNAGCCGGTATAGTCGGCACCGCCCTCAGCCTACTTATTCGTGCAGAACTCGGCCAACCAGGCACACTCCTAGGTGACGACCAGATCTACAACGTAATTGTTACCGCACATGCCTTCGTAATAATTTTCTTCATAGTCATACCAATTATGATCGGAGGATTCGGAAACTGACTTGTCCCACTCATAATCGGCGCCCCTGACATAGCCTTCCCACGCATAAACAACATAAGCTTCTGACTACTTCCCCCATCCTTCCTCCTCCTCCTAGCCTCCTCAACAGTAGAAGCAGGAGCCGGCACTGGATGAACTGTCTATCCCCCACTGGCTGGCAACATAGCCCATGCCGGAGCTTCAGTAGACCTAGCCATCTTCTCCCTTCACTTAGCCGGAGTCTCATCTATTCTAGGAGCAATCAACTTTATCACAACCGCCATCAACATAAAACCCCCAGCCCTCTCCCAGTACCAAACACCCCTATTTGTATGATCTGTCCTCATTACCGCTGTCCTTCTACTACTCTCACTCCCAGTCCTAGCCGCCGGTATTACTATGCTGCTTACAGACCGAAACCTAAACACAACATTCTTTGACCCCGCTGGCGGAGGAGATCCCATCCTATACCAACATCTCTTTTGATTCTTCGGACACCCAGAAGTTTACATCCTAATCCTG
-- end --

Download FASTA File
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Statistics of barcoding coverage: Buteo lineatus

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 7
Specimens with Barcodes: 7
Species With Barcodes: 1
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Conservation

Conservation Status

National NatureServe Conservation Status

Canada

Rounded National Status Rank: N4B - Apparently Secure

United States

Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding

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NatureServe Conservation Status

Rounded Global Status Rank: G5 - Secure

Reasons: Species is apparently holding its own throughout most of the large range (S4 or S5 in many states), but populations are much depressed, especially in the north, compared to historic levels. Threats may increase over next decade because of demands on habitat for human use.

Other Considerations: Apparent requirement of large tracts of suitable habitat.

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IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2012

Assessor/s
BirdLife International

Reviewer/s
Butchart, S. & Symes, A.

Contributor/s

Justification
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
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Before 1900, red-shouldered hawks were one of the most common hawk species in eastern North America. They have become less common because of hunting and destruction of their forest habitat. Red-shouldered hawks are also accidentally poisoned by insecticides. They often are not able to raise young when there is human disturbance, such as logging, near their nests.

This species is listed as threatened or endangered in several U.S. states, including Michigan. It is protected in the U.S. under the Migratory Bird Treaty Act. This species is also listed under CITES Appendix II.

IUCN Red List of Threatened Species: least concern

US Migratory Bird Act: protected

US Federal List: no special status

CITES: appendix ii

State of Michigan List: threatened

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Prior to 1900, this species was one of the most common hawks in eastern North America. Population densities declined substantially through most of the 20th century, probably due to hunting and destruction of wet hardwood forest habitat. Poisoning from insecticides and industrial pollutants and loss of habitat are major threats to this species. Disturbance of nesting pairs by human activity such as logging and climbing of nest trees also presents a serious threat to some populations.

This species is listed as threatened or endangered in several U.S. states, including Michigan. It is protected in the U.S. under the Migratory Bird Treaty Act. This species is also listed under CITES Appendix II, limiting international trade of individuals or body parts.

US Migratory Bird Act: protected

US Federal List: no special status

CITES: appendix ii

State of Michigan List: threatened

IUCN Red List of Threatened Species: least concern

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Global Short Term Trend: Relatively stable to increase of 25%

Comments: Breeding Bird Survey (BBS) results since 1980 indicate that populations in the eastern and western parts of the range are increasing overall, whereas the populations in the central region are more or less stable (Sauer et al. 2001). In a survey designed specifically to monitor this species, the trend in southern Ontario appears to be fluctuating but stable overall, 1990-2000 (Badzinski et al. 2000). The explanation for this change appears to be that in the Northeast, regrowth of forests harvested in the late 1800s has begun to provide more suitable habitat. However, even though there are some signs of stabilization or improvement, the present populations remain much lower than historical populations throughout the majority of the northern half of the range. In the southern part of the range, populations are apparently doing well, with the possible exception of those in Texas (Sauer et al. 2001). The amount of available habitat in the south is apparently greater than in the north, may be less threatened, and the species is apparently less sensitive to human presence and disturbance. Lack of quantitative data from much of its southern range leaves open the question of overall status.

Global Long Term Trend: Decline of 30-70%

Comments: Prior to 1900, widely reported to be the most common diurnal woodland raptor. Declined as mature forests were harvested or selectively cut. Most of the decline in the Northeast occurred in the more agricultural and more urbanized states, especially near the coast between Boston and Washington and the Lake Ontario Plain of New York. Christmas Bird Count (CBC) data indicate that from 1950 to 1969 populations declined at an overall rate of 65-74% for Ohio, 75-84% for Indiana and Michigan, and 85-94% for Illinois and Wisconsin (Brown 1971). Population levels still are greatly depressed compared to 100 years ago in most of the range. Within the Northeast and Northcentral regions there are only few places where it is still more common than the red-tailed hawk, as it once was in most areas.
Since 1970, the decline has apparently ceased or reversed in many areas, particularly in the eastern half of the range. Migration counts on the east coast for 1972-1987 showed no consistent trend (Titus and Fuller 1990) and suggest no significant recovery from low populations of the early 1970s (USFWS 1987, Bednarz et al. 1990). Appeared on the Blue List compiled and published in American Birds from 1982 through 1986 (Tate 1986). Contributors reported the species "greatly down" in the Northeast Maritime and Ontario regions, "greatly down-down" in the Hudson-Delaware and Appalachian regions, and "down" in the Southern Atlantic Coast and Middlewestern Prairie regions. Other areas did not report a decline.

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Population

Population Trend
Increasing
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Threats

Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable

Comments: Favored habitat has been reduced, modified or destroyed. Since the European settlement of the Northeast beginning in the 17th century, but especially since the 19th century, forests have been cleared for lumber, agriculture, urban and suburban development, and wetlands have been drained. In addition to complete removal of forest cover, selective harvest of valuable hardwoods or firewood also has reduced suitable habitat. Bryant (1986) studied 1953-78 aerial photographs and nest records to determine the influence of selective logging in Ontario. Incursions by red-tailed hawks were strongly associated with reductions in mean tree density and tree-crown diameter, suggesting that selective cutting in woodlots may result in the replacement of red-shouldered by red-tailed hawks. Craighead and Craighead (1969) and Postupalsky (1989) documented replacement of red-shouldered by red-tailed hawks in Washtenaw County, Michigan, that was apparently associated with changes in woodlot size and structure. Failure to maintain adequate uncut buffer zones around traditional nest sites might result in the local extirpation of the species (Bryant 1986). Habitat is increasing in some areas as farms are abandoned and revert to forest (Crocoll and Parker 1988). For example in 1900 in New York a full 75% of the land was opened or cleared for farming. Today, more than 61% of New York's land area is forested (Considine and Frieswyk 1982). New York's total forested acreage increased by 3.4 million acres (+23%) between 1950 and 1980 (Considine and Frieswyk 1982). Similar increases in forest land is true of other Northeastern states, and some Northcentral states as well. Not all reforested land will become appropriate habitat. The mature forest structure required may or may not develop, depending largely on timber harvest practices and development patterns. Ebbers (1989) pointed out that the practice of highgrading forest stands eliminates large, low-branching trees, such as American beech, that have low timber value, but are favored nesting sites. On the other hand, the practice of leaving such trees for their wildlife values as den sites and for beechnut production is beneficial. Populations potentially could be impacted by nest site competitors. Bent (1937), Stewart (1949) and Devereaux and Mosher (1984) noted the close proximity of barred owls to red-shouldered hawks during the breeding season and commented that the two species habitat requirements are similar. In fact, barred owls have been documented using old red-shoulder nests (Bent 1937, Crocoll and Parker 1986). Cooper's hawks (ACCIPITER COOPERII) (Peck and James 1983) and great horned owls (Bent 1937) have also been observed to use red-shouldered hawk nests. Both broad-winged hawks (Armstrong and Euler 1983, Crocoll and Parker 1989) and particularly red-tailed hawks (Titus and Mosher 1981, Bednarz and Dinsmore 1982, Bryant 1986) are mentioned as potential competitors for nest sites. In Ontario, broad-wings were found to use dense, deciduous-dominated mixed forests with higher ground cover in comparison to red-shoulders which nested in mature open deciduous forests with low ground cover (Armstrong and Euler 1983). Further, broad-wings are often found near partially open forests whereas red-shoulders usually are restricted to closed forests (Titus and Mosher 1981, Armstrong and Euler 1983, Crocoll and Parker 1989). Red-shouldered and red-tailed hawks may compete for nest sites (Bent 1937, Craighead and Craighead 1956). In many areas, red-tailed hawks have replaced red-shoulders as the dominant diurnal woodland hawk, though this is related more to changes in habitat than to simple competition for nest sites. In contrast to red-shoulders, red-tails prefer forests with less canopy cover and smaller woodlot size (Bednarz and Dinsmore 1982), decreased tree densities and crown diameters (Bryant 1986), and tend to nest closer to the tops of trees with greater nest openness and often on slopes (Titus and Mosher 1981, Bednarz and Dinsmore 1982). Tree diseases, especially of favored nesting trees (beech, chestnut, maple, etc.) may have a locally or regionally significant impact, as may the defoliation of vast expanses of Northeast forest by gypsy moths, pear thrips, or other insect species (Crocoll, in press). Bosakowski and Smith (1989) found that increasing human disturbance (off-road vehicles, suburban activities, horseback riders, joggers, turkey hunters, party gangs, unauthorized campers) is pushing this sensitive species to the deepest, wildest areas left in the Pequannock watershed of northern New Jersey. Although some hawks, particularly in the southern part of their range, are seemingly unaffected by human presence (Glen Johnson, pers. comm.; Jim Cox, pers. comm.), most are apparently secretive and avoid areas of human use. Hands et al. (1989) summarized recent studies documenting the relationship between nest sites and human use areas. The average distance from nest to a road was 69 m and 156 m in two Missouri studies, and 840 m in an Iowa study. Shooting from sites such as Hawk Mountain, Pennsylvania, used to take a major toll, but the changing legal and social climate has provided this "chicken hawk" (Knight 1908) far more protection than it enjoyed formerly. A number of contaminants have been found in the eggs and tissues of red-shouldered hawks: DDE, DDD, DDT, dieldrin, heptachlor epoxide, hexochlorobenzine, PCBs, mercury, chlordane, dieldrin, Furadan 10 (10% carbofuran, a carbamate), organochlorine, and polychlorinated biphenyls (Hands et al. 1989, Havera and Duzan 1986). Decreases in eggshell thickness were detected in the early 1970s, but were apparently less severe than in accipiters, falcons, ospreys (PANDION HALIAETUS), and bald eagles (HALIAEETUS LEUCOCEPHALUS) and probably had little detrimental effect on reproductive performance in the red-shoulder (Henny et al. 1973). Contaminants in water or reduced water quality can have indirect detrimental effects by reducing the amphibian prey base (Castrale 1991).

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Management

Restoration Potential: The potential for restoration in areas now devoted to agriculture or those now subject to urban/suburban sprawl is obviously low. The potential for recovery in forested and reforesting parts of its range is good (Crocoll and Parker 1988), but only if these forests are allowed to develop a mature canopy structure. It is also important to retain tracts sufficiently large to support breeding pairs. This will depend upon the cooperation of private landowners, as well as managers of public lands in each state. Compatible timber management may be possible, but has yet to be demonstrated. In Michigan, cooperative efforts by state forest and wildlife managers have begun and may provide the opportunity to monitor and develop compatible management of hardwood stands. Active management of land for hawks and preservation of large stands of mixed deciduous and coniferous trees are warranted to maintain viable populations of this species in the northern part of its range.

Preserve Selection and Design Considerations: Much of the literature indicates the need for large stands of forest for maintenance of breeding hawks. Bednarz and Dinsmore (1981) stated that red-shoulders needed a minimum of 250 ha of forest area for breeding in floodplain habitats. In most areas seem to need tracts of at least 100-250 ha (but may use smaller forest patch if it is part of a larger forested ecosystem) (Bushman and Therres 1988). Generally replaced by the red-tailed hawk in fragmented open forests. Bryant (1986), however, found that even in small woodlots of less than 5 ha red-shoulders were not replaced by red-tailed hawks when mature canopy structure was retained. Average size of woodlots occupied by red-shoulders in his southern Ontario study was only 17.5 ha. The necessary size of woodlot is clearly an issue that needs to be resolved. If large tracts are generally necessary, this requirement limits the potential for private land to provide refugia for this species. This is especially true in areas where urban or suburban development pressures are extreme. The large blocks of both upland and wetland forest in state and federal ownership in many states are therefore the most likely sites for the hawk. Reversion of abandoned farmland to forest offers potential future sites for reestablishment or expansion of present populations.

Management Requirements: While the urgency of special management is at present uneven across its range, over the long-run the requirement for mature forest habitat will continue to place it in jeopardy. Unless forest management plans take into account the special needs of the species, it is likely that the next round of forest harvest will impact hawks at least as severely as the first round. Starting from the current depressed populations, this could easily lead to the extirpation of this species from some regions. Management involves the management of both habitat and people. These procedures generally follow those for other forest-interior breeding birds (Bushman and Therres 1988), and recent management suggestions for the red-shouldered hawk specifically (Hands et al. 1989).

Timber practices have a significant impact on populations. Bednarz and Dinsmore (1981) maintained that tree densities on the order of 150 to 400 trees per acre are desirable. For the northeastern U.S., Peterson and Crocoll (1992) stated that selective cutting that creates small openings in large forest stands may be the best habitat management treatment. Robinson (1991) stated that uneven-age management with small clearings in bottomlands is best. However, too much selective cutting in woodlots may result in replacement of this species by red-tailed hawk. Group selection or standard selection cutting results in small openings scattered throughout a canopy of large overstory hardwoods (Nelson and Titus 1989) with an approximately 70% crown closure (Bushman and Therres 1988). Bryant (1986) theorized that managing for a crown closure of greater than 70% should prevent red-tailed hawks from displacing red-shouldered hawks. However, there is disagreement on the value of small clearings and the best structure of forests. Some studies show that small clearings benefit red-tailed hawks more than red-shoulders (Hands et al. 1989). Ebbers (1989) found that of two areas studied, the one with higher recruitment had taller nest trees, higher density and dominance indices; in other words, more mature forest structure. The latter study did not present forest structure in terms of canopy closure, but did present data showing that wetland openings averaged only 3% of habitat within a 1-km radius of 30 nest sites in northern Lower Michigan. Although no definitive management recommendations can yet be made, research suggests that establishment and maintenance of mature to overmature bottomland stands of at least 250 ha with > 70% crown closure, appropriately shaped nest trees, and open wetland inclusions should be the goal of red-shouldered management.

In active nesting areas, human use and passage should be minimized or prohibited during nesting season (approximately March through July for the northern range). Disturbances in the nesting territory should be minimized until the young are at least two weeks old (Bushman and Therres 1988). The best size for an undisturbed buffer zone around nest sites is not well documented. Recorded distances between nests and human use areas range from 69 to 840 m. Evers (1992) recommmended that a distance of at least 300 ft from the nest should be kept free from human disturbance.

The Allegheny National Forest Land and Resource Management Plan contains guidelines for protecting raptor nests which Nelson and Titus (1989) contended would be useful for managing hawks. These include minimizing disturbances near nest sites, reducing habitat change and closing roads to public use during the breeding season. More details can be found in Nelson and Titus (1989). These management procedures and programs work best as part of a cohesive whole, aimed at management of forest ecosystems, and accomplished through a combination of public relations and education, agency rules and regulations, and environmental laws.

States in the Northeast should each establish a restoration/recovery program, based upon state and regional needs. Recovery teams should work with landowners and foresters to assure that group selection or standard selection cutting is used to best preserve habitat during silvicutural activities.

Management Research Needs: Determine the impact of human intrusion on breeding birds. Test the effect of different buffer zone sizes.

Obtain better information on specific habitat requirements for better management of viable populations. This is particularly important in the Northeast where red-shoulders are found in both bottomland floodplain forests and upland forests.

Determine the minimum size of a forest stand necessary to maintain a breeding pair or a viable population of red-shoulders.

Monitor the impact of red-tailed on red-shouldered hawks and study the effect of various silvicultural activities on adjacent pairs of each species.

Evaluate the importance of breeding and wintering habitat to the survival of red-shoulders. Which is more critical?

See Hands et al. (1989) for additional research and management needs.

Biological Research Needs: Migratory routes and wintering areas in particular should be better identified.

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Global Protection: Many to very many (13 to >40) occurrences appropriately protected and managed

Comments: Several states report many occurrences protected via public land ownership. However, presence in a state or national forest alone does not constitute protection for this species if forest management targets harvest of mature hardwoods.

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Relevance to Humans and Ecosystems

Benefits

Economic Importance for Humans: Negative

Though red-shouldered hawks usually eat rodents and other small mammals, they occasionally eat poultry, making them a nuisance to farmers. Many of these hawks are killed annually by farmers for this reason. Red-shouldered hawks are sometimes called “hen hawk" because of this.

Negative Impacts: crop pest

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Economic Importance for Humans: Positive

Red-shouldered hawks prey on rodents that are agricultural pests.

Positive Impacts: controls pest population

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Economic Importance for Humans: Negative

Though red-shouldered hawks primarily eat rodents and other small mammals, they occasionally attack poultry, making them a nuisance to farmers. Many of these hawks are killed annually by farmers for this reason. The nickname "hen hawk" for red-shouldered hawks comes from their tendency to take advantage of poultry farms.

Negative Impacts: crop pest

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Economic Importance for Humans: Positive

Red-shouldered hawks prey on rodents that are agricultural pests.

Positive Impacts: controls pest population

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Risks

Stewardship Overview: A large woodland hawk, widespread in the eastern United States, extreme southeastern Canada, California and Mexico. Once the most common woodland hawk in the eastern region, this hawk is now much reduced in the northern part of its range. In many areas it has been replaced by the red-tailed hawk as the most common hawk. This decline came largely before 1970, and in the northeastern part of its range, some areas have seen the beginnings of recovery since that date. In the Northcentral states, the hawk is still declining, or stable at very low population size. In the southern part of its range, it is much more common. A species of large stands of mature hardwoods, or mixed hardwoods and conifers. It requires mature canopy structure with large, low-branching hardwoods for nesting, and prefers areas with wetland openings nearby. To maintain this species, particularly in its northern range, will require comprehensive forest management planning. Research on the status, productivity and response to various management practices is needed.

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Wikipedia

Red-shouldered hawk

The red-shouldered hawk (Buteo lineatus) is a medium-sized hawk. Its breeding range spans eastern North America and along the coast of California and northern to northeastern-central Mexico. Red-shouldered hawks are permanent residents throughout most of their range, though northern birds do migrate, mostly to central Mexico. The main conservation threat to the widespread species is deforestation.

Description[edit]

Males are 38 to 58 cm (15 to 23 in) long and weigh on average 550 g (1.21 lb). Females are slightly larger at 47 to 61 cm (19 to 24 in) in length and a mean weight of 700 g (1.5 lb). The wingspan can range from 90 to 127 cm (35 to 50 in).[2][3][4][5] Adult birds can vary in mass from 460 to 930 g (1.01 to 2.05 lb). Among standard measurements, the wing bone is 28–35 cm (11–14 in) long, the tail is 16–24 cm (6.3–9.4 in) long and the tarsus is 7.5–9 cm (3.0–3.5 in).[6] Adults have brownish heads, reddish chests, and pale bellies with reddish bars. Their tails, which are quite long by Buteo standards, are marked with narrow white bars. Red "shoulders" are visible when the birds are perched. These hawks' upper parts are dark with pale spots and they have long yellow legs. Western birds may appear more red, while Florida birds are generally paler. The wings of adults are more heavily barred on the upper side. Juvenile red-shouldered hawks are most likely to be confused with juvenile Broad-winged Hawks, but can be distinguished by their long tails, crescent-like wing markings, and a more flapping, Accipiter-like flight style. In direct comparison, it is typically larger and longer proportioned than the Broad-wing, though is slightly smaller and more slender than most other common North American Buteos. This bird is sometimes also confused with the widespread Red-tailed Hawk. That species is larger and bulkier, with more even-sized, broad wings and is paler underneath, with a reddish tail often apparent. The Red-tail is also more likely to soar steadily, with wings in a slight dihedral.

Taxonomy[edit]

The red-shouldered hawk is a member of the genus Buteo, a group of medium-sized raptors with robust bodies and broad wings. Members of this genus are known as buzzards in Europe, but hawks in North America.[7]

There are five recognized subspecies of Buteo lineatus, which vary in range and in coloration:[8]

  • B. l. lineatus (Gmelin, 1788)
  • B. l. alleni
  • B. l. elegans
  • B. l. extimus
  • B. l. texanus

Distribution and habitat[edit]

A pair of Red-shouldered hawks. Painted by John James Audubon.

An eastern population ranges west through s. Canada from s. New Brunswick and w. Ontario to eastern edge of U.S. Great Plains, south to Florida, Gulf Coast, and e. Mexico. Only northernmost populations are migratory. A western population breeds west of Sierra Nevada from North California to North Baja California, and has recently expanded into Oregon and Arizona, and east of the Sierra Mountains in California.

Eastern population winters from s. Wisconsin, Oklahoma, Ohio and s. New England south to Gulf Coast; occasionally throughout breeding range. In winter, reported south to Jalisco, state of México, and Veracruz, Mexico. Western population largely non-migratory. Throughout its winter range, this species avoids higher elevations.

Eastern birds occasionally wander west (e.g., Colorado, Kansas, West Texas, Manitoba, North Dakota) in migration; Western birds have strayed east to Arizona, Nevada, Idaho, and Utah, and north to Washington.[9]

In the East, individuals from the northern half of the species’ range are migratory. In the West, most populations are sedentary. Red-shouldered hawks are short- to moderate-distance migrants, with most individuals traveling distances between 300 km and 1,500 km each way. The species follows leading lines, migrating along inland ridges and coastlines. Larger numbers of red-shouldered hawks are counted at coastal watchsites than at inland sites. Juveniles often precede adults on migration in autumn, whereas adults precede juveniles in the spring. Red-shouldered hawks typically migrate alone, although they sometimes form small flocks of three or more birds. The species usually avoids crossing large bodies of water. While migrating, red-shouldered hawks are observed in soaring, gliding, and flapping flight [10]

Red-shouldered hawks are forest raptors. In the East, they live in bottomland hardwood stands, flooded deciduous swamps, and upland mixed deciduous–conifer forests. They tend to live in stands with an open subcanopy, which makes it easier for them to hunt. They are not exclusively birds of deep forest, though; one can find red-shouldered hawks in some suburban areas where houses or other buildings are mixed into woodlands. In the West, they live in riparian and oak woodlands, and also in eucalyptus groves and some residential areas.[11]

Behavior[edit]

Woodbridge, Connecticut, April 2002. By Tony Phillips.

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Diet[edit]

Red-shouldered hawks search for prey while perched on a treetop or soaring over woodlands. When they sight prey, they kill it by dropping directly onto it from the air. They may cache food near their nest for later consumption.[12] When in clearings, they sometimes fly low to surprise prey. red-shouldered hawks, like most raptors, have very sharp vision and reasonably good hearing, with talons capable of killing animals at least equal to their own size. Small mammals are typically the most important prey, especially rodents. Voles, gophers, mice, moles and chipmunks may locally be favored based on abundance. Slightly larger mammals, such as rabbits and tree squirrels, are also occasionally predated. Other prey can include amphibians, reptiles (especially small snakes), small birds, and large insects. They will attack birds as large as pigeons. Blue jays, a potential prey species, sometimes habitually imitate the call of the red-shouldered hawk and are known to be difficult to distinguish on voice alone.[13] During winters, red-shouldered hawks sometimes habituate to preying on birds commonly found at bird feeders. In some areas where they are common, crayfish can be important prey for this species. Unusual food items recorded for the species have included turnal animals such as Eastern Screech Owls and flying squirrels and road-killed deer.[14]

Reproduction[edit]

The breeding habitats of the red-shouldered hawk are deciduous and mixed wooded areas, often near water. They have been known to nest near residential areas and open water but this is much less common.[15] Red-shouldered hawks select sites with greater tree species richness for nesting.[16] Like almost all raptors, the red-shouldered hawk is monogamous and territorial. While courting or defending territories, the distinctive, screaming kee-aah call (usually repeated three to four times) of this bird is heard. Courtship displays occur on the breeding grounds, and involve soaring together in broad circles while calling, or soaring and diving toward one another. Males may also perform the "sky-dance" by soaring high in the air, and then making a series of steep dives, each followed by a wide spiral and rapid ascent. These courtship flights usually occur in late morning and early afternoon.

Red-shouldered hawks' mating season is between April and July, with activity usually peaking between April and mid-June. The breeding pair builds a stick nest (also sometimes including shredded bark, leaves and green sprigs) in a major fork of a large tree. They often use the same nest year after year, refurbishing it annually with sticks in the spring. The clutch size is typically three to four eggs. The blotchy-marked eggs, often brown to lavender in color, measure on average 54.5 mm × 43 mm (2.15 in × 1.69 in). The incubation period can range from 28 to 33 days. Hatching is asynchronous, with the first chick hatching up to a week before the last. The hatchlings, which weigh 35 g (1.2 oz) at first, are brooded almost constantly by the female for up to 40 days. Pairs that nest earlier in the breeding season tend to lay greater numbers of eggs and have higher productivity from those eggs.[17] The male more often captures food but will also incubate and brood occasionally. The young leave the nest at about six weeks of age, but remain dependent on the parents until they are 17 to 19 weeks old. They may continue to roost near the nest site until the following breeding season. Breeding maturity is usually attained at 1 or 2 years of age.

Although they have lived as long as within a month of 20 years old, few live half that long and only around half survive their first year. Each year overall nesting success can be lower than 30 percent.[18] Early mortality can be due to natural causes, relating to harsh weather conditions, or more often starvation. Young hawks are often parasitized by species such as Trichomonas gallinae, Protocalliphora avium, and blood parasites.[19] Humans, unintentionally or intentionally are a threat to red-shouldered hawks, including hunting, collision with electric wires, road accidents and logging. A further common cause of mortality is natural predation. Raccoons, martens, fishers and large arboreal snakes can predate eggs, hatchlings, fledgings and occasionally incubating and brooding adults. Non-nesting adults, being a fairly large and powerful predator, have fewer natural predators, but (both during and after the breeding season) they may be predated by great horned owls, red-tailed hawks, barred owls, other red-shouldered hawks, northern goshawks, Eurasian eagle-owls, peregrine falcons, prairie falcons, and bald and golden eagles. Many of the same predators sometimes compete over territory and food with this species. In Florida, red-shouldered hawks sometimes collaborate and peaceably coexist with American Crows (usually an enemy to all other birds because of their egg-hunting habits) so they cooperatively mob mutual predators, mainly great horned owls and red-tailed hawks.

Status[edit]

Prior to 1900, the red-shouldered hawk was one of the most common North American raptors. Population densities have decreased precipitously due to the clearing of mature forests (principally the wet hardwood forest they prefer) since that time. The changing of habitats has led to a general population increase of the Red-tailed Hawk, an occasional predator of its cousin. Additionally affecting the red-shouldered hawk was the greater availability of firearms in the early 1900s, leading to unchecked hunting of this and all other raptor species until conservation laws took effect in the latter half of the 20th century. Local forest regrowth and the ban of hunting has allowed red-shouldered hawk populations to become more stable again and the species is not currently considered conservation dependent. In Florida, the red-shouldered hawk is perhaps the most commonly seen and heard raptor species.[20] However, human activity, including logging, poisoning from insecticides and industrial pollutants, continue to loom as threats to the species.Before its use was outlawed in the United States, red-shouldered hawks and other raptors suffered from exposure to DDT, a pesticide. The DDT would cause their eggs to have thin, breakable shells, reducing their ability to reproduce. Accidental encounters with power lines and automobiles also take a toll on hawks. In spite of these dangers, habitat loss remains the biggest threat to red-shouldered hawks.[4]

In art[edit]

John James Audubon illustrates the red-shouldered hawk in his book

Gallery[edit]

References[edit]

  1. ^ BirdLife International (2012). "Buteo lineatus". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ^ ADW: Buteo lineatus: INFORMATION. Animaldiversity.ummz.umich.edu. Retrieved on 2012-12-19.
  3. ^ Red-Shouldered Hawks, Red-Shouldered Hawk Pictures, Red-Shouldered Hawk Facts – National Geographic. Animals.nationalgeographic.com (2012-12-13). Retrieved on 2012-12-19.
  4. ^ a b Red-shouldered Hawk (Buteo lineatus). Tpwd.state.tx.us. Retrieved on 2012-12-19.
  5. ^ Red-shouldered Hawk, Life History, All About Birds – Cornell Lab of Ornithology. Allaboutbirds.org. Retrieved on 2012-12-19.
  6. ^ Raptors of the World by Ferguson-Lees, Christie, Franklin, Mead & Burton. Houghton Mifflin (2001), ISBN 0-618-12762-3
  7. ^ "Buteo lineatus (J. F. Gmelin, 1788)". Integrated Taxonomic Information System, North America. Retrieved 2007-09-12. 
  8. ^ Kirschbaum, Kari; S. Miller (2000). "Buteo lineatus – red-shouldered hawk". Animal Diversity Web. University of Michigan. Retrieved 2007-09-12. 
  9. ^ Red-shouldered hawk. The Birds of North America Online. Retrieved 2014-02-25.
  10. ^ Red-shouldered Hawk (Buteo lineatus). Hawk Mountain. Retrieved 2104-02-27.
  11. ^ Red-shouldered Hawk, Life History, All About Birds – Cornell Lab of Ornithology. Allaboutbirds.org. Retrieved on 2014-02-25.
  12. ^ Buteo lineatus red-shouldered hawk. Animal Diversity Web. Retrieved 2014-02-25.
  13. ^ BFL: Species Account: Red-shouldered Hawk. Birds.cornell.edu. Retrieved on 2012-12-19.
  14. ^ Dykstra, C. R., J. L. Hays, M. M. Simon and F. B. Daniel (2003). "Behavior and Prey of Nesting Red-Shouldered Hawks in Southwestern Ohio". Journal of Raptor Research 37 (3): 237–246. 
  15. ^ Daniel, F., Dykstra, C., Hays, J., Simon M. (2001). "Correlation of Red-Shouldered Hawk Abundance and Macrohabitat Characteristics in Southern Ohio". The Condor 103 (3): 652–656. 
  16. ^ King, J. C.; Dubay, S. A.; Woodford, J. E. (2011). "Distribution and nest site selection of red-shouldered hawks (Buteo lineatus) in forests of northeastern Wisconsin (USA)". Forest Ecology and Management 261: 169. doi:10.1016/j.foreco.2010.10.001.  edit
  17. ^ Morrison, J. L.; McMillian, M.; Cohen, J. B. and Catlin, D. H. (2008). "Environmental correlates of nesting success in red-shouldered hawks". The Condor 109 (3): 648–657. 
  18. ^ Woodford, J. E.; Eloranta, C. A.; Rinaldi, A. (2008). "Nest Density, Productivity, and Habitat Selection of Red-Shouldered Hawks in a Contiguous Forest". Journal of Raptor Research 42 (2): 79. doi:10.3356/JRR-07-44.1.  edit
  19. ^ King, J. C.; Dubay, S. A.; Huspeni, T. C.; Vanlanen, A. R.; Gerhold, R. W. (2010). "Parasite Infections in Nestling Red-Shouldered Hawks (Buteo lineatus) in Northeast Wisconsin". Journal of Parasitology 96 (3): 535. doi:10.1645/GE-2130.1. PMID 20557199.  edit
  20. ^ The Raptors of Southwest Florida » Naples Daily News. Naplesnews.com (206-05-16). Retrieved on 2012-12-19.
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Red-shouldered Hawk

The Red-shouldered Hawk (Buteo lineatus) is a medium-sized hawk. Its breeding range spans eastern North America and along the coast of California and northern to northeastern-central Mexico. Red-shouldered Hawks are permanent residents throughout most of their range, though northern birds do migrate, mostly to central Mexico. The main conservation threat to the widespread species is deforestation.

Description[edit]

Males are 38 to 58 cm (15 to 23 in) long and weigh on average 550 g (1.21 lb). Females are slightly larger at 47 to 61 cm (19 to 24 in) in length and a mean weight of 700 g (1.5 lb). The wingspan can range from 90 to 127 cm (35 to 50 in).[2][3][4][5] Adult birds can vary in mass from 460 to 930 g (1.01 to 2.05 lb). Among standard measurements, the wing bone is 28–35 cm (11–14 in) long, the tail is 16–24 cm (6.3–9.4 in) long and the tarsus is 7.5–9 cm (3.0–3.5 in).[6] Adults have brownish heads, reddish chests, and pale bellies with reddish bars. Their tails, which are quite long by Buteo standards, are marked with narrow white bars. Red "shoulders" are visible when the birds are perched. These hawks' upper parts are dark with pale spots and they have long yellow legs. Western birds may appear more red, while Florida birds are generally paler. The wings of adults are more heavily barred on the upper side. Juvenile Red-shouldered Hawks are most likely to be confused with juvenile Broad-winged Hawks, but can be distinguished by their long tails, crescent-like wing markings, and a more flapping, Accipiter-like flight style. In direct comparison, it is typically larger and longer proportioned than the Broad-wing, though is slightly smaller and more slender than most other common North American Buteos. This bird is sometimes also confused with the widespread Red-tailed Hawk. That species is larger and bulkier, with more even-sized, broad wings and is paler underneath, with a reddish tail often apparent. The Red-tail is also more likely to soar steadily, with wings in a slight dihedral.

Taxonomy[edit]

The Red-shouldered Hawk is a member of the genus Buteo, a group of medium-sized raptors with robust bodies and broad wings. Members of this genus are known as buzzards in Europe, but hawks in North America.[7]

There are five recognized subspecies of Buteo lineatus, which vary in range and in coloration:[8]

  • B. l. lineatus (Gmelin, 1788)
  • B. l. alleni
  • B. l. elegans
  • B. l. extimus
  • B. l. texanus

Distribution and Habitat[edit]

An eastern population ranges west through s. Canada from s. New Brunswick and w. Ontario to eastern edge of U.S. Great Plains, south to Florida, Gulf Coast, and e. Mexico. Only northernmost populations are migratory. A western population breeds west of Sierra Nevada from n. California to n. Baja California, and has recently expanded into Oregon and Arizona, and east of the Sierra Mountains in California.

Eastern population winters from s. Wisconsin, Oklahoma, Ohio and s. New England south to Gulf Coast; occasionally throughout breeding range. In winter, reported south to Jalisco, state of México, and Veracruz, Mexico. Western population largely non-migratory. Throughout its winter range, this species avoids higher elevations.

Eastern birds occasionally wander west (e.g., Colorado, Kansas, w. Texas, Manitoba, North Dakota) in migration; Western birds have strayed east to Arizona, Nevada, Idaho, and Utah, and north to Washington.[9]

In the East, individuals from the northern half of the species’ range are migratory. In the West, most populations are sedentary. Red-shouldered Hawks are short- to moderate-distance migrants, with most individuals traveling distances between 300 km and 1,500 km each way. The species follows leading lines, migrating along inland ridges and coastlines. Larger numbers of Red-shouldered Hawks are counted at coastal watchsites than at inland sites. Juveniles often precede adults on migration in autumn, whereas adults precede juveniles in the spring. Red-shouldered Hawks typically migrate alone, although they sometimes form small flocks of three or more birds. The species usually avoids crossing large bodies of water. While migrating, Red-shouldered Hawks are observed in soaring, gliding, and flapping flight [10]

Red-shouldered Hawks are forest raptors. In the East, they live in bottomland hardwood stands, flooded deciduous swamps, and upland mixed deciduous–conifer forests. They tend to live in stands with an open subcanopy, which makes it easier for them to hunt. They are not exclusively birds of deep forest, though; you’ll find Red-shouldered Hawks in some suburban areas where houses or other buildings are mixed into woodlands. In the West, they live in riparian and oak woodlands, and also in eucalyptus groves and some residential areas.[11]

Behavior[edit]

Diet[edit]

Red-shouldered hawks search for prey while perched on a treetop or soaring over woodlands. When they sight prey, they kill it by dropping directly onto it from the air. They may cache food near their nest for later consumption.[12] When in clearings, they sometimes fly low to surprise prey. Red-shouldered Hawks, like most raptors, have very sharp vision and reasonably good hearing, with talons capable of killing animals at least equal to their own size. Small mammals are typically the most important prey, especially rodents. Voles, gophers, mice, moles and chipmunks may locally be favored based on abundance. Slightly larger mammals, such as rabbits and tree squirrels, are also occasionally predated. Other prey can include amphibians, reptiles (especially small snakes), small birds, and large insects. They will attack birds as large as pigeons. Blue jays, a potential prey species, sometimes habitually imitate the call of the Red-shouldered Hawk and are known to be difficult to distinguish on voice alone.[13] During winters, Red-shouldered Hawks sometimes habituate to preying on birds commonly found at bird feeders. In some areas where they are common, crayfish can be important prey for this species. Unusual food items recorded for the species have included turnal animals such as Eastern Screech Owls and flying squirrels and road-killed deer.[14]

Reproduction[edit]

The breeding habitats of the Red-shouldered Hawk are deciduous and mixed wooded areas, often near water. They have been known to nest near residential areas and open water but this is much less common.[15] Red-shouldered hawks select sites with greater tree species richness for nesting.[16] Like almost all raptors, the Red-shouldered Hawk is monogamous and territorial. While courting or defending territories, the distinctive, screaming kee-aah call (usually repeated three to four times) of this bird is heard. Courtship displays occur on the breeding grounds, and involve soaring together in broad circles while calling, or soaring and diving toward one another. Males may also perform the "sky-dance" by soaring high in the air, and then making a series of steep dives, each followed by a wide spiral and rapid ascent. These courtship flights usually occur in late morning and early afternoon.

Red-shouldered Hawks' mating season is between April and July, with activity usually peaking between April and mid-June. The breeding pair builds a stick nest (also sometimes including shredded bark, leaves and green sprigs) in a major fork of a large tree. They often use the same nest year after year, refurbishing it annually with sticks in the spring. The clutch size is typically three to four eggs. The blotchy-marked eggs, often brown to lavender in color, measure on average 54.5 mm × 43 mm (2.15 in × 1.69 in). The incubation period can range from 28 to 33 days. Hatching is asynchronous, with the first chick hatching up to a week before the last. The hatchlings, which weigh 35 g (1.2 oz) at first, are brooded almost constantly by the female for up to 40 days. Pairs that nest earlier in the breeding season tend to lay greater numbers of eggs and have higher productivity from those eggs.[17] The male more often captures food but will also incubate and brood occasionally. The young leave the nest at about six weeks of age, but remain dependent on the parents until they are 17 to 19 weeks old. They may continue to roost near the nest site until the following breeding season. Breeding maturity is usually attained at 1 or 2 years of age.

Although they have lived as long as within a month of 20 years old, few live half that long and only around half survive their first year. Each year overall nesting success can be lower than 30 percent.[18] Early mortality can be due to natural causes, relating to harsh weather conditions, or more often starvation. Young hawks are often parasitized by species such as Trichomonas gallinae, Protocalliphora avium, and blood parasites.[19] Humans, unintentionally or intentionally are a threat to Red-shouldered Hawks, including hunting, collision with electric wires, road accidents and logging. A further common cause of mortality is natural predation. Raccoons, martens, fishers and large arboreal snakes can predate eggs, hatchlings, fledgings and occasionally incubating and brooding adults. Non-nesting adults, being a fairly large and powerful predator, have fewer natural predators, but (both during and after the breeding season) they may be predated by Great Horned Owls, Red-tailed Hawks, Barred Owls, other Red-shouldered Hawks, Northern Goshawks, Eurasian Eagle-Owls, Peregrine Falcons, Prairie Falcons, and Bald and Golden Eagles. Many of the same predators sometimes compete over territory and food with this species. In Florida, Red-shouldered Hawks sometimes collaborate and peaceably coexist with American Crows (usually an enemy to all other birds because of their egg-hunting habits) so they cooperatively mob mutual predators, mainly Great Horned Owls and Red-tailed Hawks.

Status[edit]

Prior to 1900, the Red-shouldered Hawk was one of the most common North American raptors. Population densities have decreased precipitously due to the clearing of mature forests (principally the wet hardwood forest they prefer) since that time. The changing of habitats has led to a general population increase of the Red-tailed Hawk, an occasional predator of its cousin. Additionally affecting the Red-shouldered Hawk was the greater availability of firearms in the early 1900s, leading to unchecked hunting of this and all other raptor species until conservation laws took effect in the latter half of the 20th century. Local forest regrowth and the ban of hunting has allowed Red-shouldered Hawk populations to become more stable again and the species is not currently considered conservation dependent. In Florida, the Red-shouldered Hawk is perhaps the most commonly seen and heard raptor species.[20] However, human activity, including logging, poisoning from insecticides and industrial pollutants, continue to loom as threats to the species.Before its use was outlawed in the United States, red-shouldered hawks and other raptors suffered from exposure to DDT, a pesticide. The DDT would cause their eggs to have thin, breakable shells, reducing their ability to reproduce. Accidental encounters with power lines and automobiles also take a toll on hawks. In spite of these dangers, habitat loss remains the biggest threat to red-shouldered hawks.[21]

In art[edit]

John James Audubon illustrates the Red-shouldered Hawk in his book

Woodbridge, Connecticut, April 2002. By Tony Phillips.

Problems playing this file? See media help.

Gallery[edit]

References[edit]

  1. ^ BirdLife International (2012). "Buteo lineatus". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ^ ADW: Buteo lineatus: INFORMATION. Animaldiversity.ummz.umich.edu. Retrieved on 2012-12-19.
  3. ^ Red-Shouldered Hawks, Red-Shouldered Hawk Pictures, Red-Shouldered Hawk Facts – National Geographic. Animals.nationalgeographic.com (2012-12-13). Retrieved on 2012-12-19.
  4. ^ Red-shouldered Hawk (Buteo lineatus). Tpwd.state.tx.us. Retrieved on 2012-12-19.
  5. ^ Red-shouldered Hawk, Life History, All About Birds – Cornell Lab of Ornithology. Allaboutbirds.org. Retrieved on 2012-12-19.
  6. ^ Raptors of the World by Ferguson-Lees, Christie, Franklin, Mead & Burton. Houghton Mifflin (2001), ISBN 0-618-12762-3
  7. ^ "Buteo lineatus (J. F. Gmelin, 1788)". Integrated Taxonomic Information System, North America. Retrieved 2007-09-12. 
  8. ^ Kirschbaum, Kari; S. Miller (2000). "Buteo lineatus – red-shouldered hawk". Animal Diversity Web. University of Michigan. Retrieved 2007-09-12. 
  9. ^ [1]. The Birds of North America Online. Retrieved 2014-02-25.
  10. ^ Red-shouldered Hawk(Buteo lineatus- Hawk Mountain Hawk Mountain. Retrieved 2104-02-27.
  11. ^ Red-shouldered Hawk, Life History, All About Birds – Cornell Lab of Ornithology. Allaboutbirds.org. Retrieved on 2014-02-25.
  12. ^ [2] Animal Diversity Web. Retrieved 2014-02-25.
  13. ^ BFL: Species Account: Red-shouldered Hawk. Birds.cornell.edu. Retrieved on 2012-12-19.
  14. ^ Dykstra, C. R., J. L. Hays, M. M. Simon and F. B. Daniel (2003). "Behavior and Prey of Nesting Red-Shouldered Hawks in Southwestern Ohio". Journal of Raptor Research 37 (3): 237–246. 
  15. ^ Daniel, F., Dykstra, C., Hays, J., Simon M. (2001). CORRELATION OF RED-SHOULDERED HAWK ABUNDANCE AND MACROHABITAT CHARACTERISTICS IN SOUTHERN OHIO. The Condor 103(3), 652-656.
  16. ^ Dubay, S., King, J., Woodford J. (2011). Distribution and nest site selection of red-shouldered hawks (Buteo lineatus) in forests of northeastern Wisconsin (USA). Forest Ecology and Management 261(1), 169–177.
  17. ^ MORRISON, J., McMILLIAN, M., COHEN, J., CATLIN, D. (2008). ENVIRONMENTAL CORRELATES OF NESTING SUCCESS IN RED-SHOULDERED HAWKS. The Condor 109(3), 648-657.
  18. ^ Woodford, J.,Eloranta, C., Rinaldi A. (2008). Nest Density, Productivity, and Habitat Selection of Red-Shouldered Hawks in a Contiguous Forest. Journal of Raptor Research 42(2), 79-86.
  19. ^ King, J., Dubay, S., Huspeni, T., VanLanen, A., Gerhold R. (2010). Parasite Infections in Nestling Red-Shouldered Hawks (Buteo lineatus) in Northeast Wisconsin. Journal of Parasitology 96(3), 535-540.
  20. ^ The Raptors of Southwest Florida » Naples Daily News. Naplesnews.com (206-05-16). Retrieved on 2012-12-19.
  21. ^ [3] Texas Parks and Wildlife. Retrieved 2014-02-25.
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Notes

subspecies of buteo lineatus

there are four subspecies of buteo lineatus :B.L.ALLENI,B.L.ELEGANS,B.L.EXTIMUS,B.L.TEXANUS.

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Names and Taxonomy

Taxonomy

Comments: Five subspecies have been recognized. The nominate LINEATUS, formerly FALCO LINEATUS, is based on the "barred-breasted buzzard" of Latham and the "red-shouldered falcon" of Pennant (AOU 1983). The other four subspecies include ALLENI of the southeastern U.S., EXTIMUS of extreme southern Florida, TEXANUS of Texas and northeastern Mexico, and ELEGANS of the west coast.

Palmer (1988) stated that "the red-shoulder fits better morphologically in ASTURINA than in BUTEO," and placed it in the former as ASTURINA LINEATA. Most authors have retained this species in the genus BUTEO.

The red-shouldered hawk and Ridgway's hawk, B. RIDGWAYI, a resident on Hispaniola and surrounding small islands (Beata, Gonave, Isle-a-Vache, Alto Velo, Grand Cayemite and Petite Cayemite) might constitute a superspecies (AOU 1983).

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