Violet-green Swallows

Violet-green Swallows are Abundant in Western Washington mainly from End of February-September may go into Oct with late nesting ones or ones from farther north. They spend most of the time in the air eating flying insects such as Mayflies, Fleas, Mosquitoes, Crane Flies, Small Bees, Carpenter Ants, Small Flies, Sand Flies, Water Beetles, Damselflies, Lady Bugs, Midges, Lacewings, Snake-flies, Grasshoppers, Leaf-hoppers have been seen with Yellowjackets but not regular.
Habitat 
Is cities, towns, suburbs, villages, fields, farmlands, marshes, swamps, lakes, ponds especially riparian, rivers, prairies, lagoons, estuaries, clear-cuts, woods, burns, airports. Nesting in dead trees, nest boxes, buildings with holes and eaves.

Behavior

These social birds are often found in flocks of mixed-swallow species and in single-species flocks. They are highly acrobatic and forage almost exclusively in flight. Their flight is more fluttery than that of Tree Swallows, and they often fly higher than other swallow species. They will, however, feed low over open water, especially in bad weather.

Female

Note that the species dose a Pre-dawn song before sun gets up from May-June