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Chaetura vauxiVaux's swift

By Dave So

Geographic Range

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)

Habitat

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)

Physical Description

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
    0.53 to 0.78 oz

Reproduction

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)

  • Average eggs per season
    5
    AnAge
  • Average time to hatching
    19 days
    AnAge

Lifespan/Longevity

Behavior

Vaux's swifts move primarily by flight. They fly continuously unless they are perched in their nest or roost. They fly fast and erratically. Sometimes the fast and rapid movements give the visual impression that the wings are not always synchronized. Swifts are known to fly basically anywhere. They do not, however, walk or hop. When entering their nest, swifts fly in head-first, but once they are inside the next, they turn around to alight tail-first. (Bull, Collins 1993)

Vaux's swifts do not appear to be very territorial. Swifts do indeed chase each other often, but for the most part during mating season. (Bull, Collins 1993)

Communication and Perception

Food Habits

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)

Conservation Status

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.

Contributors

Dave So (author), University of Michigan-Ann Arbor, Tanya Dewey (editor), Animal Diversity Web.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

taiga

Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.

visual

uses sight to communicate

References

Bull, E., C. Collins. 1993. Vaux's Swift. The Birds of North America, No. 77: 1-12.

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