Violet-green Swallow

The Violet-green Swallow (Tachycineta thalassina) is a small, slender passerine renowned for its elegant, swift flight and shimmering plumage. A quintessential bird of western North America, it is often seen carving tight circles high in the sky in search of flying insects. Highly social and tolerant of humans, these swallows frequently nest in suburbs and parks, bringing their vibrant colors and cheerful chattering to backyard birders.

Identifying the Violet-green Swallow is easiest when paying attention to its facial patterns and rump color.

Key Field Marks

• The Head and Face: Unlike other swallows, the clean white plumage of the throat wraps up and around the eye. This creates a distinct white frame around the dark eye, coupled with a deep green crown on the head.
• The Back and Rump: The upperparts display a brilliant, iridescent bronze-green on the back, transitioning to a rich violet-purple on the rump and upper tail coverts. This coloration is highly reflective and varies depending on the angle of the light.
• The Underparts: Completely clear, unmarked snowy white from the throat down to the undertail coverts.
• The Flanks: Notable white patches flare up on the sides of the rump, nearly meeting over the base of the tail. This is a crucial field mark when viewing the bird in flight from above.

Similar Species

• Tree Swallow (Tachycineta bicolor): The Tree Swallow has a blue-green back and lacks the white patches on the sides of the rump. Crucially, the dark cap of a Tree Swallow extends down below the eye, which is encapsulated in dark plumage, unlike the white-wrapped eye of the Violet-green.

The Violet-green Swallow is exclusively a western species in North America.

Range and Migration

• Breeding Range: They breed from central Alaska and western Canada down through the western United States to central Mexico.
• Wintering Range: They are medium-distance migrants, spending winters in Mexico and Central America, with some populations staying along the southern California coast.

Preferred Habitats

They favor open or semi-open habitats, especially near water where insect populations are high. This includes deciduous, coniferous, and mixed woodlands, mountain canyons, cliffs, and increasingly, suburban parks and residential areas.

Violet-green Swallows are master aeronauts that spend the vast majority of their active hours on the wing.

Feeding and Flight

These birds feed strictly on the wing, catching flying insects including flies, beetles, wasps, and wild bees. They tend to forage higher in the air than other swallow species, making tight, sweeping turns. On windy days, they may hunt lower over the surface of lakes and rivers.

Vocalization

Their call is a series of rapid, high-pitched, metallic squeaks and twittering notes, often transcribed as a sharp tsip or chee-chee. During the breeding season, males perform a very early morning "dawn song" consisting of repeated, rapid chirps.

Nesting and Breeding

As cavity nesters, they historically relied on old woodpecker holes in dead snags, rock crevices in steep canyon walls, or cliffs. Today, they readily adapt to artificial nest boxes. They are known to nest in loose colonies and will sometimes aggressively defend their nesting sites from other cavity-nesting species.