This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the violet-green swallow.
This is a bird seen fluttering high in the sky in the company of swifts or zipping across open water and fields at speeds approaching those of the peregrine falcon. It catches and eats insects midair, relying completely on the availability of aerial insects for food.
Unlike the closely related tree swallow, which can eat some berries when insects are not available, the violet-green must retreat south when freezing weather drives insects from the skies. Most spend the winter in Mexico or Central America. In the breeding season, the violet-green is a swallow of the West, found in the western third of the United States and into western Canada and Alaska.
Often nesting in small groups, these cavity nesters are found in open woodlands with deciduous and evergreen trees as long as there are standing dead ones. Like many secondary cavity nesting species, they primarily depend on woodpeckers to excavate holes where they can build their nests. People join woodpeckers in providing nest sites with man-made nest boxes.
Violet and green would be a more appropriate name for these birds whose metallic green backs and purple rumps can appear iridescent in sunlight. In flight, look for a bright white belly, and a white back patch formed by patches on the flanks that almost meet on the rump. Their short tails appear square or only slightly notched.
It is easier to observe the facial pattern formed by white from the throat which extends behind and above the eyes when the birds are perched. It is possible to distinguish sexes in a view that shows the mottled face pattern of the female or clean white of the male.
Violet-green swallows were one of the victims when an alarming sudden die-off of migratory birds occurred primarily in New Mexico in September of 2020. Hundreds of thousands of birds perished in a short period of time. Causal factors are thought to include a sudden cold snap, exacerbated by extended drought and wildfire smoke that left the birds in poor physical condition.
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