Perception Channels: visual ; tactile ; acoustic ; chemical
Vaux's Swifts have been experiencing some decline in their natural habitat due to the destruction of older forests, which they select as habitat due to the abundance of old, hollow trees. Also, chimneys are becoming less of an option due to the movement away from brick chimneys and towards insulated pipes. Old, hollow trees where Vaux's live are being saved on some National Forest lands. For the trees that do fall, action is taken to replace them.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
The main foods consumed year round are insects and spiders. During the breeding season, Vaux's swifts soar above the forest canopy and swoop down, pausing at a tree to feed on insects flying near the tree. These swifts are generally spotted soaring above mature forests approximately 20 to 50 meters above the top of the canopy. (Bull, Collins 1993)
During the breeding season, Vaux's swifts feed both in flocks and alone. They capture prey mid-flight. When feeding nestlings, swifts return to the nest with a mouth full of food items. Generally, during the breeding season, these items consisted of flies, hoverflies, ants, bees, planthoppers, aphids, spindlebugs, lanternflies, bark beetles, moths, mayflies, true bugs, and spiders. (Bull, Collins 1993)
Chaetura vauxi, commonly known as Vaux's Swift, can be found anywhere from southwestern Canada to the western United States, and in Mexico, Central America, and northern Venezuela. Their breeding range includes western North America from southeast Alaska, northwest and southern British Columbia, northern Idaho and western Montana south to central California. The southern breeding range consists of the Yucatan Peninsula, western Mexico, and as far south as Panama and Venezuela. (Bull, Collins 1993)
Vaux's Swifts that do indeed migrate reside north of Mexico and migrate south. They arrive in the north in late April to early May and migrate south between mid-August to late September. Swifts generally fly in large flocks. Swifts that live in southern regions are most likely residents. Swifts can be found during the winter time in central Mexico south to Middle America and Venezuela, sometimes in central California. (Bull, Collins 1993)
Biogeographic Regions: nearctic (Native ); neotropical (Native )
Vaux's Swifts generally can be found in old-growth forests consisting of coniferous and deciduous vegetation. Very important to swifts' nesting grounds are large, hollow trees that are either dead or alive. (Bull, Collins 1993)
During the breeding season, Vaux's swifts occupy forests of coast redwood and Douglas firs. They forage for food in naturally occuring openings in the forest and along streams as well as high above the tree-tops. In the Yucatan, swifts have been seen nesting on the sides of limestone wells. (Sutton and Phelps 1948)
Terrestrial Biomes: taiga ; forest ; scrub forest
Average lifespan
Status: wild: 61 months.
Chaetura vauxi are the smallest swifts in North America. The length of their body is generally 11 cm. Size cannot be used to determine gender. Vaux's swifts are designed for speed; they posses an aerodynamic shape with long, pointed wings, short and blunt humeri, and a small body. These swifts have short legs and small feet. The bill is short and stout. (Bull, Collins 1993)
Both sexes have very similar plumage, plain grayish brown appearance sometimes highlighted by a slight green iridescence. "Rump and upper tail coverts range from a pale brownish gray to a duller shade like that of the back" (Wetmore 1957). The upper breast and throat area are paler than the rest of their underbelly. (Bull, Collins 1993)
Range mass: 15 to 22 g.
Other Physical Features: endothermic ; bilateral symmetry
Vaux's swifts pair off around May shortly after arriving to the breeding grounds. In northeast Oregon swifts begin the construction of their nest during the month of June, while nest construction begins in May in western Oregon (Thompson 1977). Incubation occurs between mid-June and late July. Nestlings appear early July till early September. Fledglings develop between late July till early September. (Bull, Collins 1993)
As for parental behavior, incubation of the eggs starts only after the entire clutch of eggs is laid. Eggs are constantly wtached by both adults. Both adults share responsibility for incubating eggs. Mating and parenting is usually monogamous, but there are reports of three swifts feeding one brood. This suggests cooperative breeding, similar to that seen in the Chimney Swift. (Bull, Collins 1993)
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average time to hatching: 19 days.
Average eggs per season: 5.
Vaux's swift (Chaetura vauxi) is a small swift native to North America, Central America, and northern South America. It was named for the American scientist William Sansom Vaux.
This is a small swift, even compared to other Chaetura species, at 10.7 to 11.2 cm (4.2 to 4.4 in) long and weighing 18 g (0.63 oz). The northern populations are slightly larger at 11.5 cm (4.5 in), probably according to the Bergmann's Rule and/or migration requirements. It has a cigar-shaped body, crescentic wings and a short bluntly squared-off tail. The head, upperparts and wings are dusky black, and the underparts, rump and tail coverts are greyish brown. The throat is paler grey, becoming whitish in northern birds. The sexes are similar, but juveniles have dusky bases to the throat feathers.
Vaux's swift breeds in highlands from southern Alaska to central California and from southern Mexico, the northern Yucatán Peninsula, to eastern Panama and northern Venezuela. The United States' populations are migratory, wintering from central Mexico south through the Central American breeding range. The resident breeding birds in the southern part of the range are sometimes considered a separate species, dusky-backed swift, Chaetura richmondi. Preferred habitats include old growth coniferous or deciduous forests consisting of coniferous and deciduous vegetation; requires large, hollow trees for nesting.
This is a gregarious species, with flocks of 30 or more birds, and often with other swift species, such as white-collared, especially at weather fronts. It flies with a mixture of stiff wing-beats and unsteady glides. It has more varied calls than others in the genus, with a mixture of chattering, buzzes, squeaks and chips.
The swift feeds in flight on flying insects, including beetles, wasps, termites and flying ants. It forages over forests and more open areas, including towns.
Vaux's swift breeds in the mountains and foothills, from southeastern Alaska and Montana to central California, mainly above 700 m (2,300 ft). It builds a cup nest of twigs and saliva on a vertical surface in a dark cavity, such as a tree hole, cliff crevice or attic. It lays three white eggs between March and July. It spends winters in the tropics.
Vaux's swift builds saucer-shaped nests of twigs or spruce and pine needles stuck to an inside surface of a hollow tree or chimney, between 20 inches and 6 feet from the bottom of the cavity.[2]
The following seven subspecies are recognized by the International Ornithological Congress as of early 2021:[3]
The former subspecies Chaetura vauxi andrei of eastern Venezuela was recognised as a distinct species, the ashy-tailed swift, by the South American Classification Committee of the American Ornithological Society (AOS) in June 2020 and the IOC in January 2021.[4][5][3]
A migratory population of Vaux's swifts roost each Autumn in the old brick chimney of Chapman Elementary School in Northwest Portland, Oregon. They are locally and regionally known as "Chapman swifts" in part because packing thousands of birds into a brick chimney each evening, is a visual treat that draws large crowds. [6]
These birds should not be confused with the Chapman's swift of Brazil, Columbia, Ecuador and other nations in South America; who are a different species entirely. The Portland Oregon flock is North America's largest concentration of Vaux's swifts.
Every evening from mid-August to mid-October, thousands of Vaux's swifts gather in the sky over the school, then between sunset and dark, fly into a tall brick chimney to roost for the night. Thousands of birds flock in great living tornados, then funnel into the chimney. Estimates of 1,700 to 35,000 swifts have been reported in various years. Shortly after sunset, over a period of roughly 30 minutes, they fly into the top of the brick chimney (constructed c.1925) to roost on the interior surface until they depart at sunrise.[7] The school is on the birds' migratory route to their wintering sites in southern Central America and Venezuela.[8]
The swifts attract predators, such as owls, Peregrine falcons and Cooper's hawks, as well as hundreds to thousands[7][9] of human spectators.[10]
The birds began using the site in the early 1980s in response to the loss of much of their natural roosting habitat — old growth Douglas-fir and forest snags.[11] Vaux's swifts prefer roosting in standing hollow trees.[8]
To protect the swifts, the school stopped using its heating system during the weeks of roosting. Students and teachers wore sweaters and jackets, especially toward the end of September when classroom temperatures can drop to 50 to 60 °F (10 to 16 °C).[12] Around 2003, the Audubon Society of Portland, school fundraisers and corporate sponsors donated $60,000[11] to $75,000[13] for an alternate school heating system which is independent of the brick chimney. The chimney is now maintained solely for the use of the birds.
Vaux's swift (Chaetura vauxi) is a small swift native to North America, Central America, and northern South America. It was named for the American scientist William Sansom Vaux.
