Chaetura vauxi

Vaux's Swift

Family: Apodidae · Class: Aves · Order: Apodiformes

Conservation status: G5 S3

Vaux's Swift is a small aerial insectivore measuring 10.8 to 11.4 cm (4.25 to 4.5 inches) in length with a wingspan of 27 to 30 cm (10.6 to 11.8 inches). The species weighs 17 to 22 grams. Adults display sooty brown to grayish-brown upperparts with slightly paler underparts showing a grayish-brown wash. The throat appears pale gray to whitish. Wings are long, narrow, and crescent-shaped, characteristic of swifts. The tail is short and square-tipped with protruding shaft tips beyond the vanes. Sexes appear similar, though males average slightly smaller. Juveniles show paler edges on wing coverts and back feathers. Vaux's Swift breeds from southeastern Alaska through British Columbia and western North America south to Venezuela. In California, the species occurs primarily in the Coast Ranges from Humboldt County south to Santa Barbara County, and in the Sierra Nevada from Shasta County to Tulare County. The breeding range extends from sea level to approximately 2,440 meters (8,000 feet) elevation. California populations are migratory, with birds arriving in April and departing by September for wintering grounds in Central and South America. The species inhabits coniferous and mixed forests, particularly areas with large hollow trees for roosting and nesting. In California, Vaux's Swift shows strong association with old-growth and mature second-growth forests containing large Douglas-fir, redwood, and other conifers with suitable cavities. During migration, flocks may roost communally in chimneys, particularly in urban areas. The species requires open airspace above or adjacent to forested areas for foraging. Vaux's Swift is entirely aerial, catching insects on the wing during daylight hours. The diet consists primarily of flying ants, termites, flies, beetles, aphids, and other small aerial arthropods. Breeding occurs from May through July, with pairs nesting in hollow trees, typically in cavities 4.5 to 18 meters (15 to 60 feet) above ground. The nest is a shallow cup constructed of twigs cemented together and attached to the cavity wall with saliva. Females lay 3 to 5 white eggs, with incubation lasting 18 to 19 days. Young fledge after 28 to 30 days. During migration and roosting, the species forms large communal roosts, sometimes numbering in the thousands. Vaux's Swift holds no federal or state listing status but is designated as a California Species of Special Concern due to population declines linked to habitat loss. The species faces primary threats from logging of old-growth forests, which removes essential nesting cavities. Fire suppression practices that reduce natural cavity formation and urban development fragmenting foraging habitat also impact populations. According to the North American Breeding Bird Survey, California populations have declined approximately 3.1% annually since 1966. Conservation efforts focus on protecting old-growth forest remnants and maintaining snag habitat in managed forests.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.