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Range
 Breeds
from central Alaska, the Yukon, and western Mackenzie, east to southern
Quebec and the Maritime Provinces, and south to Florida, the West
Indies and Central America. Winters from southern Canada southward.
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Status
Uncommon resident along the coast, including
Vancouver Island and the Queen Charlotte Islands, and in the Okanagan,
Shuswap and South Thompson regions of the Thompson-Okanagan Plateau.
Uncommon summer visitant throughout the rest of the province. Casual
in winter in the interior north of latitude 51°N. Fairly common
to common migrant throughout the province. Widespread breeder. |
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Status
Change
No change |
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Nonbreeding
 The
Red-tailed Hawk is found in almost any open or semi-open habitat
from sea level to above the timberline (2,500 m). Open woodlands,
grasslands, parklands, rangeland, and agricultural fields with scattered
trees are preferred; forest clearings, alpine meadows, airports,
estuaries, and marshes are frequented seasonally.
The spectacular migratory flights that
occur in eastern North America are not evident in British Columbia.
While small numbers are occasionally reported soaring together under
certain atmospheric conditions, it appears that most movements are
of individuals. Migration routes are poorly known. The spring movement
probably follows river valleys and coastlines, and much of the autumn
movement is suspected to occur along mountain ridges and meadows.
Spring migration begins in late February
and early March in southern areas, but the main movement through
the province occurs in April, with some passage in northern areas
still evident in early May. The autumn movement begins in the latter
half of August, with most birds passing through the province in
September. The latest autumn departure date for northern areas is
31 October (Fort St. John).
The major wintering area in the province
is the Fraser Lowlands. Populations there are supplemented by birds
arriving from the north throughout November and into December (Campbell
et al. 1972b). Peaks vary, but most occur in December and February.
The Red-tailed Hawk was the most abundant year round captor next
to the Northern Harrier during counts in the Fraser River delta
and Pitt Meadows from January 1975 to May 1980 (Douglas, A. 1984).
Christmas Bird Count data indicate a steady increase in numbers
of wintering birds from the Fraser River delta and Pitt Meadows
between 1972 and 1987. In winter, at least, the Red-tailed Hawk
is now the most abundant raptor in these areas. |
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Breeding
 The
Red-tailed Hawk breeds throughout the province, including offshore
islands, from sea level to at least 2,230 m elevation. Breeding
densities are lowest in northern areas (Boreal Forest) as well as
on the Queen Charlotte Islands, northern mainland coast, and Vancouver
Island, where the diversity of preferred prey (i.e. small mammals)
is lowest. The Fraser Lowlands, probably supports the highest breeding
densities in the province and compares favourably with other areas
in North America. During a study from 1979 to 1985 in Richmond,
Runyan (1987) calculated a mean nest density of one nest per 3.6
km2. This value is higher than that of one pair per 7.0 km2, 7.2
km2, and 5.7 km2 reported in Wisconsin (Orians and Kuhlman 1956),
Alberta (Luttich et al. 1971), and New York (Hagar, D.C. 1957) respectively.
The highest density in North America was reported by Fitch et al.
(1946) as one pair per 1.3 km2 in California.
Breeding habitat varies considerably,
but is closely associated with open or semi-open country. Habitat
includes the edges of deciduous, coniferous, and mixed woodlands,
agricultural areas with woods and fence rows, parkland, river bottomlands,
woods bordering lakes, bogs, and marshes, and open woodlands on
hills. Trembling aspen and black cottonwood groves, cliffs, burns,
islands in rivers and lakes, large scattered trees bordering highways
and roads, and alpine meadows are used less frequently. |
| Nests: 
Most nests (92%; n=212) were in trees,
and most of the trees were living; the remaining nests were on cliff
ledges and in stumps. Coniferous trees (48%; 8 species) were used
slightly more than deciduous trees (44%; 4 species). Black cottonwood
(38%), Douglas-fir (19%), and ponderosa pine (19%) were the nest
trees most often used.
Nests were well-concealed and situated
in or near the tree crown, usually in a crotch or on a branch next
to the trunk. Heights of 182 tree nests ranged from 6 to 46 m, with
51% recorded between 12 and 18 m. Cliff nests were up to 76 m above
the ground.
There was a great variety of nest structures,
from compact to loosely-organized dead and living sticks and twigs.
The material ranged in diameter from 0.6 to 9 cm. Outside nest diameters
ranged from 36 to 107 cm, outside depths ranged from 23 to 122 cm.
Most nests were lined with both fresh and old conifer sprigs, as
well as strips of coniferous and deciduous bark, rootlets, leaves,
mosses, cones, grasses, feathers, and conifer needles.
Eggs:
Dates for 83 clutches ranged from 28
February to 20 June, with 53% recorded between 16 April and 6 May.
Calculated dates indicate that eggs could be found as late as 2
July. Sizes for 81 clutches ranged from 1 to 4 eggs (1E-8, 2E-38,
3E-28, 4E-7), with 81% having 2 or 3 eggs. Incubation period is
about 34 days (Hegner 1906).
Young:
Dates for 237 broods ranged from 10 April
to 9 August, with 54% recorded between 22 May and 29 June. Most
young leave the nest in July. Sizes for 174 broods ranged from 1
to 4 young (1Y-52, 2Y-97, 3Y-21, 4Y-4), with 56% having 2 young.
Fledging period is about 45 days (Beebe 1974). |
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Remarks
Three of the seven North American Red-tailed
Hawk subspecies recognized by the American Ornithologists' Union
(1957, 1973) occur in British Columbia. Buteo jamaicensis alaseensis
breeds on the Queen Charlotte Islands (Taverner 1936; Fig. 22) and
in coastal areas including Vancouver Island. B. j. ealurus
breeds in the interior and B. j. harlani (a valid subspecies,
Mindell 1983) breeds in northern British Columbia. The precise ranges
of the subspecies are not known. |
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Nests