Vaux’s swifts return to Healdsburg

Autumn's approach has triggered the return of tiny birds that converge by the thousands each fall on a Healdsburg high school campus to feast, rest and recharge en route to wintering grounds in Central and South America.

Hundreds of Vaux's swifts already have made an appearance this year at Rio Lindo Adventist Academy near Fitch Mountain. For three decades, they've stopped there during their annual migration, treating visitors to a spectacle each evening as the birds swirl and funnel into an unused chimney to roost for the night.

About 21,000 swifts were counted one night during peak migration last fall. The most ever was more than 35,000 in 2015.

Throughout, members of the public have been welcomed onto the private campus to observe the mysterious rite that occurs at sundown, when a swarm of birds seemingly random in its flight suddenly begins circling, often forming a tight vortex leading into the safety of the chimney.

But in an effort to control the crowd size, monitor behavior and ensure the safety of more than 150 students who attend the private boarding school above the Russian River, campus personnel this year will limit entry each night to 50 vehicles. They'll also charge $10 a car, cash only, to help fund campus clubs.

“It's not that we don't want people to come,” campus spokesman Brad Benson said. But “we can't handle big crowds.”

Benson said campus administrators are charged with ensuring student safety on campus during the school year. In some years, when crowds have reached 350 or even 450, they've had trouble tracking who goes where.

In addition, some spectators in years past have drunk alcohol and smoked while visiting, violating school rules and the Adventist faith's embrace of abstention from tobacco and alcohol.

“People should know better,” Benson said. “There's no smoking or drinking on any campus.”

The school is trying to strike a balance between having too many people and allowing nature enthusiasts who can be respectful to observe the swifts. Benson said those who want to make sure to get on campus should visit during the week, when fewer people generally come out.

Like their hummingbird cousins, the Vaux's swifts are small, light birds that can fly 60 to 80 mph. They have fixed wings and a wingspan of about a foot.

They travel around 10,000 miles each year, from breeding grounds in British Columbia and southern Alaska to Mexico, Central America and Venezuela, where they spend the winter months, stopping along the way to rest and feed.

Logging and development have decreased the availability of hollow trees, the swifts' traditional roosting sites. But they have found man-made alternatives, including numerous chimneys along the western migration route, many monitored by a network of observers.

They've roosted at Rio Lindo academy since 1989, when the chimney and connected boiler were no longer used full time.

After a day of roaming far and wide to feast on gnats and other insects, the swifts create the “bird tornado” observers describe seeing at sunset.

“I think it's one of the most interesting ornithological phenomena in Sonoma County,” Peter Leveque, a retired Santa Rosa Junior College biologist, said this week. “I go every year, three or four times.”

Leveque said it's likely some of the birds stay for two or three nights in Healdsburg, though others may need less time to lay down some fat and continue their flight.

The birds do nearly everything in flight - including copulation - and have bristly hairs on the edge of their bills that help widen the net for catching gnats and mosquitoes as they fly.

Benson said about 4,000 birds were counted Monday night, but the peak will probably not be reached until late next week. It usually falls between Sept. 10-20, he said.

The school is located at 3200 Rio Lindo Ave., in Healdsburg. For more information, visit www.riolindo.org.

You can reach Staff Writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.