Vaux's Swifts at Chapman: The Twenty-Thousand-Bird Spiral

Every year from mid-August to mid-October, starting around dusk, something begins to happen above Chapman Elementary School in Northwest Portland that has no precedent in the behavior of most American cities. The Vaux's Swifts arrive.

Vaux's Swifts are small birds, roughly the size of a swallow, that migrate along the Pacific Flyway each autumn from their northern breeding grounds toward wintering territory in Central and South America. They need a warm, sheltered shaft to roost in at night. For decades, they have used the brick chimney at Chapman Elementary School.

The birds gather in the sky above the school beginning in the late afternoon. There may be twenty thousand of them, sometimes more, swirling in an enormous vortex that narrows as it approaches the chimney mouth. The spiral tightens. Then, beginning at one edge of the formation, the birds begin to pour into the chimney, a stream of wings folding into a shaft barely three feet across. The process takes thirty to forty-five minutes to complete.

Thousands of Portlanders bring blankets, wine, and folding chairs to the adjacent park hillside to watch. The Portland Audubon Society monitors the roost each year and publishes the nightly counts. The event has no admission fee and no organized programming. It happens because the chimney is there and the birds need it.

Chapman Elementary School's facilities staff leaves the chimney uncapped during swift season, a decision the school district has maintained for decades because the roost is considered part of what Portland is. The swifts return each year on roughly the same schedule. They do not appear to be aware that they have become a tourist attraction.