Bird of the Month: Vaux's Swift
By Hugh Jennings
Scientific Name: Chaetura vauxi
Length 4.75 in
Wingspan 12 in
Weight 0.6 oz
AOU Band code VASW
The Vaux’s Swift (VASW) is about 4.75” long with a wingspan 12” and a weight of 0.6 oz. (17g). The genus name Chaetura (kee-TOO-rah) is Latin from the Greek chaite, stiff hair, bristle, or spine, and oura, tail: spine-tailed. Its genus name is the same as for the Chimney Swift, the eastern U.S. counterpart to the Vaux’s. The species name vauxi (VAUKS-eye) is for the 19th-century Philadelphia naturalist, William Sansom Vaux.
It is our smallest N.A. swift and is referred to as a “flying cigar”. The VASW is dark gray-brown above and paler below the throat and on the chest. It has a short square tail and long, thin pointed scimitar-shaped wings. The short, spine-tipped tail helps prop the swift up when clinging to a vertical surface. These spines are difficult to see in flight.
Their range is the west coast from British Columbia to Northern California and are found in open skies over woodlands, lakes and rivers, feeding on a variety of insects. They often feed low over the water in morning and evening. Their flight is rapid, jerky and erratic like a bat. The calls consist of high-pitched chip notes followed by an insect-like trill in flight.
They are a fairly common summer resident in moist forests throughout WA state, and in cities in forested areas. During fall migration they gather in large numbers at favorite roosts, such as smokestacks. To see this spectacle come to the September Swift Night Out Festival in Monroe. Fall migration is by day and most probably go to Mexico or the northern coast of the Gulf of Mexico.
Nests are made with a sticky saliva-like substance to glue twigs and pine needles to the wall of a hollowed-out tree or chimney. The VASW prefers old-growth forests where there are holes in rotted snags. Usually six white eggs are laid but will vary from 3-7. Incubation is by both sexes over 18-19 days. Both parents care for and feed the nestlings with other adults helping parents incubate the eggs and feed the young. First flight is after 3-4 weeks and the young may return to roost at the nest site for several days. There is only one brood per year.