Vaux's Swift is a small swift

Swift

The swifts are a family, Apodidae, of highly aerial birds. They are superficially similar to swallows, but are actually not closely related to passerine species at all; swifts are in the separate order Apodiformes, which they share with hummingbirds...

 native to North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and northern South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. It was named for the American scientist William Sansom Vaux

William Sansom Vaux

William Sansom Vaux was an American mineralogist. He was born in Philadelphia. He became a member of the Academy of Natural Sciences in 1834, and served it in various capacities in the next forty-eight years, including vice-president...

.

Description

This is a small swift, even compared to other Chaetura species, at 10.7 to 11.2 cm long and weighing 18 g. The northern populations are slightly larger at 11.5 cm, probably according to the Bergmann's Rule

Bergmann's Rule

Bergmann's rule is an ecogeographic principle that states that within a broadly distributed genus, species of larger size are found in colder environments, and species of smaller size are found in warmer regions. Although originally formulated in terms of species within a genus, it has often been...

, 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.

Distribution

Vaux's Swift breeds in highlands from southern Alaska

Alaska

Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 to central California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 and from southern Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, the northern Yucatán Peninsula

Yucatán Peninsula

The Yucatán Peninsula, in southeastern Mexico, separates the Caribbean Sea from the Gulf of Mexico, with the northern coastline on the Yucatán Channel...

, to eastern Panama

Panama

Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...

 and northern Venezuela

Venezuela

Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

. The United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

' populations are migratory

Bird migration

Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

, wintering from central Mexico south through the Central America

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

n breeding range. The resident breeding birds in the southern part of the range are sometimes considered a separate species, Dusky-backed Swift, Chaetura richmondi.

Behaviour

This is a gregarious species, with flocks of 30 or more birds, and often with other swift species, such as White-collared

White-collared Swift

The White-collared Swift, Streptoprocne zonaris, is a resident breeding bird from central Mexico, the Greater Antilles and Trinidad south to Peru, northern Argentina and southeastern Brazil....

, 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.

Feeding

The swift feeds in flight on flying insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s, including beetle

Beetle

Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...

s, wasp

Wasp

The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

s, termite

Termite

Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...

s and flying ant

Ant

Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

s. It forages over forests and more open areas, including towns.

Breeding

Vaux's Swift breeds in the mountains and foothills, mainly above 700 m. 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.
Habitat
Vaux's Swift: Breeds from southeastern Alaska and Montana to central California. Spends winters in the tropics. Preferred habitats include old growth coniferous or deciduous forests consisting of coniferous and deciduous vegetation; requires large, hollow trees for nesting.

External links

• Vaux's Swift photo, Article Umatilla County, Oregon
• Article & RangeMaps InfoNatura NatureServe
• Vaux's Swift photo gallery VIREO