Distinguishing Features
A large western swift with long
wings, and decidedly forked tail (without spine-like projections).
Upper parts brownish-black or sooty-brown, white line over eye.
Sides blackish with white patches
on either side of the rump, the throat, breast and median part of
the abdomen. Total length 15 - 18 cm. (Godfrey, 1986)
Distribution
Columbia Basin: Local distribution
throughout the s. part of the Columbia Basin.
British Columbia: White-throated
Swifts are moderately widespread, being locally distributed as far
north as Williams Lake, the Chilcotin River, and Clearwater, and
as far east as the East Kootenays (Summers 1995).
Global: Breeds from south central
British Columbia and southern Alberta south in the mountains to
Guatemala, El Salvador, and Honduras. Winters from central California,
central Arizona, and southwest New Mexico southward to limits of
breeding range, (Godfrey 1986).
Habitat
White-throated Swifts are usually
observed in their aerial habitat near towering cliffs and canyons
in the dry interior. They breed in small colonies on steep cliffs
among rocky bluffs or in canyons.
Threats
Nesting habitat is generally not
very threatened by human activities. However, there is possible
abandonment of nesting sites in response to mine blasting and housing
development. There is also the potential for disturbance from rock-climbing
and hang-gliding, although the impacts of these activities are unknown
at this time. Insect control programs and land development that
destroys insect-producing habitats have the potential to effect
local populations by reducing available forage (Cannings et al.
In prep.).
Biology
In British Columbia nesting occurs at 300 - 800
m elevation, and colonies consist of 2 - 40 birds (average is 8).
The nest is a shallow-cupped saucer of feathers, grass and other
plant material, glued together with the bird's saliva. Nests are
glued into cracks, crevices, and small, protected ledges on precipitous
rocky cliffs at sites that are inaccessible to almost all terrestrial
predators. Once breeding is established, they return traditionally
to the same nest site year after year (Cannings et al. In prep.).
Little is known about breeding ecology because of the inaccessibility
of nest sites. Clutch size is typically 4 or 5 eggs, but the incubation
and fledging periods are unknown. Adults have been observed exhibiting
incubation behaviour as early as May 16, and feeding young between
June 9 and August 16 (Cannings et al. In prep.).
