The violet-green swallow (Tachycineta thalassina) is a small North American swallow.
Their breeding habitat is semi-open areas in western North America from Alaska to Mexico. They nest in cavities in a tree or rock crevice, sometimes forming small colonies.
They migrate in flocks to Central and northern South America.
These birds often forage in flocks, usually flying relatively high but sometimes flying low over water. They eat insects including mosquitoes, butterflies, mayflies and moths. source