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Birds return to make nightly visit to unused JBLM structure

Migrating swifts find comfort roosting in familiar chimney

eam members (from left) Timothy Leque, Sanders Freed and Burney Huff watch for Vaux’s swifts during a recent bird count. Photos by Scott Hansen/JBLM PAO

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Every night for the last month, a group of birds has circled a chimney on Joint Base Lewis-McChord just before sunset. It starts with just a few, but more and more join them as they swoop around their target - and then, as it finally gets dark, they swirl into the structure at high speeds to roost for the night.

"What you can witness is spectacular," bird watcher Larry Schwitters said.

The nightly event is part of the Vaux's swifts annual migration north. These small, gray birds are only a bit larger than a swallow and live in Central America and parts of Mexico for most of the year. Each spring they move up the coast to nest in the forests of the Pacific Northwest, going as far as northen Canada - and among their stops on the way is a brick chimney at the corner of Division Street and Pendleton Avenue on JBLM.

In spite of their ecological importance to the region, little is known about the birds. But the JBLM site is part of a project devoted to learning more.

A chimney might seem like a strange roosting place for a bird, but the Vaux's swifts have special needs in this area. The birds have no back talons on their feet, and so they cannot perch. Instead, they use their front talons to cling, typically hanging vertically along the insides of hollow trees. The birds sometimes roost together by the thousands, perhaps for warmth.

As logging and development make large, hollow trees increasingly rare, the birds have taken to clinging to the mortar joints between bricks on old chimneys.

"They're trying to make up for it by using man-made structures," Schwitters said.

This was part of the reason that Schwitters created the Vaux's Happening website, which tracks the birds' biannual trips. Though the birds are likely endangered, very little is known about them. In 2007, Schwitters began coordinating Audubon Societies and other volunteers to help him identify and monitor chimneys on the migration route. Vaux's Happening started that year with two chimneys in Washington state. Now there are more than 100 sites on the watch list, from Yukon, Canada to Mexico City.

The project came to JBLM in 2008 when someone notified wildlife biologist Sanders Freed of a bat infestation in an old, unused chimney near the thrift store on Lewis Main. He knew right away that he were dealing with birds, and in time a group formed to gather data for Vaux's Happening. It turns out the chimney is among the most active (known) roost sites in thes state.

Though he usually works with bats, Freed volunteers one night a week to keep count.

"It's certainly something to see," he said.

Starting in late April each year, the swifts fly north nonstop during the day, foraging for insects in the air as they go. Little by little, they begin to spiral around the chimney starting about an hour before sunset, calling to each other as the dusk deepens. As their numbers grow, they swoop around the roost site until some unknown signal tells them it's time to call it a day. Then they smoothly dive toward the top of the chimney, almost as though they're being sucked in. They do it all again toward the end of August, this time heading south.

"It's like a cyclone," Burney Huff, who coordinates the JBLM volunteers, said. "Just as they get to the top of the chimney, they sort of flutter and fall in."

Usually a bird or two will stay out for a few minutes after the main group is in for the night. Huff calls them the "last call birds," as they circle and call a few more times in case there's anyone left to hear.

This spring's migration includes reports from 55 roost sites, including two trees - though it appears to have peaked a bit earlier than usual. Huff counted 5,900 birds at the JBLM chimney on May 10, and after that the numbers dropped dramatically. The highest count since was 657 with numbers as low as five, as of press time.

The causes for the drop are unknown, though weather may be a factor.

Though Vaux's swifts are relatively unstudied, keeping track of the birds has big implications, According to Schwitters, they are an indicator species for the well-being of Pacific Northwest forests - that is, they help give signals about the biological condition of the area. As such, protecting them and their habitat is important.

"If you start pecking away at the web of life, you don't know what type of mess you're going to get yourself into," he said.

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