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

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.

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.

[5][6][4] 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.

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.

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.

[11] 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.