Vancouver Avian Research Centre

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Violet-green Swallow Tachycineta bicolor
 

Description:

Swallows and Martins are especially adapted to aerial life and in western North America this swallow can been seen on the wing in urban and rural areas.
The Violet-green Swallow is slender, sleek and the plumage is glossy or iridescent; dark above and white below. They have long pointed wings. This western swallow has a distinct white cheek extending above the eye.
This species breeds primarily in western North America from central Alaska and western Canada south to the Mexican highlands, rarely occurring east of the Rocky Mountains. It winters mostly from Mexico south to Guatemala, El Salvador, and Honduras.

Identification:

General: Small and very short-tailed swallow; wingtips project well beyond tail tip. Note white sides of rump. 13cm length, 14g weight.

Adult Male: Beneath, pure white. Above, soft velvety green or greenish bronze, with a very faint shade of purplish-violet concentrated on the nape into a transverse band. Often shows violet on the upper tail coverts.
Ear coverts partly or mainly white, almost encircling the eyes, more extensive on adult male than on female and juvenile. A white patch on each side of rump often brought close together so as to form an apparently continuous white band.

Adult female: Duller above than male.

Juvenile: Gray brown above; white except on rump may be mottled or grayish.

Similar Species: Looks smaller in flight than most other swallows. Resembles Tree Swallow, but greener above with purple gloss, white on face almost encircling the eyes, tail shorter and less forked. Also soars less and wing beats more rapid. Juveniles of both species show variable amounts of white on the flanks, so confusion between the two species is most likely in juvenal plumage Juvenile Tree Swallow shows white throat contrasting with dark ear-coverts and grayish chest; juvenile Violet-green shows dingy throat and chest, blending more gradually with darker areas on head.

Behavior: Being a swallow, this and other swallows as well as martins spend more time in daylight flight feeding and soaring than most other North American passerines. It feeds in small groups or loose flocks. Like most other swallows, they feed exclusively on insects caught in flight, often at high altitudes. They nest both solitarily and in colonies of up to 25 pairs. The birds are often highly gregarious during foraging, migration, and when away from their nests, and flocks of several hundred birds are commonly observed in these contexts.
Habitat Occurs principally in montane coniferous forests, often nesting in inaccessible sites such as abandoned woodpecker holes in tall dead snags. It is also common in western suburban areas nesting in cavities in homes and buildings.

Information:

Despite an extensive distribution, less is known about the Violet-green Swallow than nearly any other North American swallow. This swallow appears to be the western counterpart of is congener, the Tree Swallow.
Of note, the male sings courtship songs in flight in the dark before sunrise, repeating over and over tsip tseet tsip.
Females typically lay 4 to 6 eggs in an abandoned woodpecker hole, crevice in a cliff, building, or bird box, often returning to the same breeding site in successive years.

Conservation Status:

No documentation of effects on numbers. This species domesticity and ability to nest both in remote cliffs and near human habitation may have saved it from harmful human impact. The introduction of the House Sparrow and European Starling however, may have negatively influenced populations in southern Canada, particularly in urban areas.
 
Capture Rates


Migrating from Central America, the Violet-green Swallow prefers mountainous coniferous forests for breeding. The low capture rate (2010-2012; standardized as birds captured per 100 net hours) from April through June reflect the small number of Violet-green Swallows breeding at Colony Farm.

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