Vaux's Swift: Small swift, gray-brown body, sometimes highlighted by slight green iridescence. Rump is pale brown, throat and breast are nearly white. Bill, legs, feet are gray-black. Flight is low and fast, alternates bursts of quick fluttery wing beats with short glides. Catches insects in flight.
Range and Habitat
Vaux's Swift: Breeds from southeastern Alaska and Montana to central California. Spends winters in the tropics. Preferred habitats include old growth coniferous or deciduous forests consisting of coniferous and deciduous vegetation; requires large, hollow trees for nesting.
The Vaux's Swift has a large range, estimated globally at 2,200,000 square kilometers. Native to North and Central America, this bird prefers subtropical or tropical forest ecosystems as well as degraded former forests. The global population of this bird is estimated at 1,500,000 individuals and does not show signs of decline that would necessitate inclusion on the IUCN Red List. For this reason, the current evaluation status of the Vaux's Swift is Least Concern.
The Vaux's Swift is the smallest swift in North America. They have more varied calls than others in their genus.
It is named for William S. Vaux, a member of the Academy of Natural Sciences and a friend of John K. Townsend, who first described the species. The name is pronounced "vawks," not "voh."
They roost communally, by the hundreds or sometimes thousands, presumably to conserve heat. They let their body temperature drop and become torpid on cold nights, reviving in the warmth of day.
A group of swifts are collectively known as a "box", "flock", "screaming frenzy", and "swoop" of swifts.