Chaetura vauxi
The Vaux's Swift is the most common swift west of the Rockies. In late summer and early fall, large flocks may be seen circling in tight groups, prior to plunging collectively into roosting trees or chimneys. Swifts, when not in flight, use their small but strong claws to cling to vertical surfaces. While many swifts in eastern areas choose chimneys and other structures to nest and to roost in, the Vaux's Swift continues to prefer decaying trees for its rest areas in the West. John Kirk Townsend named this bird after William Sansom Vaux, an eminent mineralogist. Although Vaux well deserved the honor, it is somewhat ironic that one of the West's most aerial birds is named for a man whose passion was for earth-bound treasures. |
I.D.: Sexes similar: brownish-gray overall. In flight: brown upperparts; lighter underparts with a very pale throat; squared-off tail; long wings taper backward. Size: L 5 in. (13 cm). Range: locally common summer breeder in the Montana Rockies; rare breeder south of Wyoming. Habitat: forages in forest openings, river valleys and lakeshores and breeds in mature coniferous and deciduous forests in the foothills and the montane. Nesting: typically west of the Rockies; in a hollow tree cavity or chimney; nest is made of sticks, twigs and conifer needles and glued to the inner wall of the cavity with saliva; pair incubates 4-5 white eggs for 18-19 days. Feeding: on the wing, often just above the treetops; feeds almost entirely on flying insects, including flies, moths, ants and aphids. Voice: courtship call is a fast, twittering chip-chip-chip-cheweet-cheweet. Similar Species: Black Swift: black; much larger overall. White-throated Swift: light and dark patterning on the underparts. Bank Swallow: dark breast band on white underparts. Northern Rough-winged Swallow : dirty white underparts; heavier wings; larger tail. |
