Swallows
Tachycineta thalassina
The Violet-green Swallow is a small, agile songbird of western North America, often admired for its iridescent plumage. When illuminated by sunlight, its back shimmers with metallic green and its rump with violet. These aerial insectivores are known for their acrobatic flight as they pursue insects high in the sky.
Typical adult measurements.
Individuals and populations vary.
01 / The telltale details
Start with shape and behavior. Then look for the smaller details.
Adults display a metallic green back and an iridescent violet rump, especially vibrant in good light.
Distinctive white patches on the sides of the rump, often called 'saddlebags,' are visible even in flight.
White feathers extend onto the face, curling from behind the ear and above the eye, giving a unique facial pattern.
The belly is clean white, contrasting with the darker upperparts.
02 / A place in the world
This species breeds in diverse western habitats, including open coniferous, deciduous, and mixed forests, woodlands, and canyons. They are often found near water sources like rivers, ponds, and lakes, and may also utilize rocky cliffs or even open prairies if suitable nest sites are present.
The breeding range extends across western North America, from central Alaska and western Canada south through the western United States to Baja California and central Mexico. They winter from the southwestern United States through Mexico and into Central America, reaching as far south as Costa Rica.
Violet-green Swallows are long-distance migrants. They arrive in their northern breeding areas in spring, typically April, and depart for their wintering grounds in Mexico and Central America from July to September. Some individuals may remain in the southwestern United States during winter.
03 / Listen a little closer
In flight or during interactions with other swallows, they emit a short, twittering call.
04 / The life behind the feathers
Their diet consists entirely of flying insects, including a wide variety of flies, wasps, winged ants, bees, beetles, and moths.
These swallows are aerial insectivores, catching their prey on the wing. They often forage at higher altitudes than other swallow species but will descend to feed low over water bodies, especially during inclement weather. They typically forage in flocks, sometimes alongside other swallows or swifts.
Violet-green Swallows are secondary cavity nesters, utilizing old woodpecker holes, natural tree cavities, or rock crevices. They will also readily use nest boxes and human-made structures. The female constructs a cup-shaped nest of grasses and feathers, and typically lays 4-6 white eggs.
These are gregarious songbirds, frequently observed foraging and migrating in flocks, sometimes associating with other swallow species or swifts. They often perch on power lines or exposed tree branches. They may nest in isolated pairs or small colonies.
One more reason to pay attention
The scientific name *Tachycineta thalassina* means 'fast moving' and 'of the sea,' referring to their swift flight and greenish back.
A male Violet-green Swallow was recorded to be at least 9 years and 1 month old, making it the oldest known individual of its species.
Female Violet-green Swallows may invest more antimicrobial proteins in later-laid eggs, potentially aiding the survival of late-hatching young.
05 / An eye for the difference
Tree Swallows lack the white flank patches ('saddlebags') and the white that curls around the eye of the Violet-green Swallow.
Purple Martins are larger and entirely dark, lacking the white underparts and iridescent green and violet of the Violet-green Swallow.
Northern Rough-winged Swallows have duller, brownish upperparts and a dusky throat and breast, without the bright iridescence or distinct white markings of the Violet-green Swallow.
AI-assisted species research. Prepared September 2026. Details can vary across regions and populations.