Montana Field Guide

The smallest swift in North America. A 11 cm-long bird with long narrow wings, a small cigar-shaped body, and a short stubby tail. Size of sexes is similar. Plumage of sexes similar. Plain grayish brown, sometimes with a slight green iridescence; rump and upper tail coverts range from a pale brownish-gray to a duller shade like that of the back. Upper breast and throat paler than rest of undersides. Best known for its quick flight and dazzling aerial agility (Bull and Collins 1993).

For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.

Differs from the Chimney Swift (Chaetura pelagica) in smaller size, usually paler rump and ventral body plumage, shorter wings, and lesser tendency to soar.

During breeding prefer late stages of coniferous forests and deciduous forests mixed with coniferous. More common in old-growth forests than in younger stands. During spring and fall migrations prefer forests and open areas; roost trees and chimneys important as they allow Chimney Swifts to avoid exposure and conserve body heat. Hollow trees are its favored nesting and roosting sites (Bull and Collins 1993).

Almost entirely insects and spiders. Catches its prey from the air (Bull and Collins 1993).

Nest in hollow trees in the forest; less commonly in chimneys. In Montana, egg laying completed 22 June. Clutch sizes vary from 3 to 7 eggs (Bull and Collins 1993). Nestlings have been observed in Montana from July 16 to August 10.