Red-shouldered hawk (Buteo lineatus) COSEWIC assessment and status reportchapter 2

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Species Information

The Red-shouldered Hawk, Buteo lineatus, is a medium-sized hawk that can be distinguished by its reddish-brown shoulder patches, notched outer four primaries and less than half-feathered tarsus. Its upper parts are mainly brown, its tail blackish above and whitish below with several wide dark bars with intervening narrow white bars and a white tip. Its underparts are white with reddish-brown barring. The most common vocalization is the “kee-aah” call that is given early in the breeding season.

Distribution

The eastern and central North American breeding population ranges west through southern Canada to the eastern edge of the United States Great Plains, south to Florida, the Gulf states and eastern Mexico. In Canada, the Red-shouldered Hawk occurs in southern Ontario, Quebec and New Brunswick, with the majority of the population in Ontario. The wintering range of the Red-shouldered Hawk includes southern Wisconsin, Oklahoma, southern Ohio and southern New England south to the Gulf Coast, but they are occasionally found wintering within their Canadian breeding range. Approximately 1% of the North American Red-shouldered Hawk population breeds in Canada.  

Habitat

The Red-shouldered Hawk breeds in a variety of forest types, including bottomland hardwood, riparian areas, flooded deciduous swamps and upland mixed deciduous-coniferous forest. Nearby wetlands or other aquatic areas are essential. This species is area sensitive, preferring extensive forest stands consisting of mature to old-growth canopy trees with variable amounts of understory. Large, contiguous forest tracts are essential to sustain breeding populations of this species.

Biology

The Red-shouldered Hawk feeds on a wide variety of prey, but small mammals, amphibians and snakes comprise the bulk of their diet in most areas. Nests are usually located below the canopy and more than halfway up the tree in a crotch of the main trunk. The Red-shouldered Hawk is monogamous and lays 3–4 eggs per year. On average, pairs fledge 1.3 chicks/nest and 55.2% of nests fledge at least one chick. Adult Red-shouldered Hawks occupy the same territory for life and young tend to settle close to their natal territory.

Population Sizes and Trends

The current population estimate for the Red-shouldered Hawk in Canada is 6 270 breeding pairs or 12 540 individuals. Data from a variety of surveys suggest that the population has been stable to increasing over the last 10 to 20 years. 

Limiting Factors and Threats

The most serious threats facing the Red-shouldered Hawk include loss and fragmentation or degradation of favoured deciduous forest breeding areas and wetland feeding areas. Loss and fragmentation of habitat also have indirect effects, including reduction in prey supply and increased interspecific competition. 

Special Significance of the Species

The Red-shouldered Hawk is considered an indicator species of sustainable forest management because it is an area sensitive species that requires mature forest habitat. The Red-shouldered Hawk is also a top predator and thus may be potentially valuable as an indicator of environmental health. 

Existing Protection

This species, but not its habitat, is protected by provincial game and fish legislation. The Red-shouldered Hawk is classified as Special Concern in Canada by COSEWIC, Special Concern in Ontario and May Be At Risk in New Brunswick, although the latter is not a legal designation. In Ontario, nests on Crown land north of the Canadian Shield are protected through the application of spatial and temporal buffers.