Vaux’s Swifts are returning to Pacific Northwest chimneys for their Fall migration

One of the Pacific Northwest’s most celebrated annual bird migrations is currently underway.

Every year, Vaux’s Swifts move south through Oregon and Washington, gathering by the thousands and creating an unusual evening spectacle as flocks gather around chimneys before settling in for the night.

The small migratory bird spends the warmer months in the Pacific Northwest before heading south in the Fall toward Central America and northern South America.

Around Portland, the migration has traditionally drawn attention to Chapman Elementary School, where thousands of swifts once gathered on September evenings.

But the birds have changed their habits in recent years, making this fall’s migration a little less predictable.

Why do Vaux’s Swifts gather around chimneys?

Vaux’s Swifts spend much of their time in the air, catching insects as they fly. Unlike many familiar backyard birds, they are not built for sitting on branches or utility lines.

The birds instead cling to vertical surfaces when they rest.

According to the Bird Alliance of Oregon, Vaux’s Swifts historically relied on large hollow trees and standing snags for places to nest and roost. As those habitats became less available, some birds began using older brick chimneys that provide similar sheltered spaces.

That is why large groups can suddenly appear above a school, church, or other older building around sunset.

The birds circle above the chimney before dropping inside, sometimes by the thousands. The entire flock can disappear from the evening sky in just a few minutes.

What happened to the swifts at Chapman Elementary School?

Chapman Elementary in Northwest Portland became one of Oregon’s best-known places to watch the fall migration after swifts began using its chimney in the late 1980s.

That changed in 2024.

Bird Alliance counts reached 5,430 swifts at Chapman on Sept. 2, 2024, but numbers soon dropped dramatically. By later that month, almost no birds were using the chimney.

The swifts did not return to Chapman in significant numbers in 2025. Instead, they gathered at other chimneys around the Portland area.

The shift produced some sizable gatherings elsewhere. Abernethy Elementary recorded a peak of 7,130 swifts in 2025, while Peace Lutheran Church recorded 3,930, according to Bird Alliance monitoring.

Other roosts were documented at St. Sharbel Catholic Church, the Milwaukie Museum, and the former Oregon City High School.

Where will the swifts gather this September?

That is one of the questions Bird Alliance observers are trying to answer during the 2026 migration.

The organization did not detect swifts using the Chapman chimney during this year’s spring migration. It is now monitoring roosts again as the birds head south.

It is unclear why a large number of the birds stopped gathering at Chapman, according to Bird Alliance.

Bird Alliance researchers examined the chimney and looked at possible explanations after the 2024 change. They did not find an obvious problem with the structure or a clear connection to predators.

The organization has also documented swifts changing roosts elsewhere, meaning Chapman may simply be part of a larger movement between suitable chimneys.

For people hoping to see the birds this fall, that means Chapman is no longer the sure destination it once was.

When can people watch the swifts?

September is one of the best times to look.

According to the Bird Alliance of Oregon, the fall migration through the Portland area generally runs from late August into early October.

The best viewing happens around sunset. Swifts begin gathering in the sky near a roost before circling the chimney and heading inside as daylight fades.

Vaux’s Swifts are small, measuring roughly 4 to 5 inches long. They have dark bodies, narrow crescent-shaped wings, and quick wingbeats that can make them resemble bats from a distance.

People who notice large groups gathering around a chimney can also report the location to the organization.