The Disappearing Habitats of the Vaux’s Swifts- page 1 | Science | Smithsonian
No one knows exactly where Vaux's (pronounced "vauks") swifts spend the winter, or the details of their migration route. But we do know the birds need chimneys. (AP Photo / The Press Democrat, John Burgess)

The Disappearing Habitats of the Vaux’s Swifts

Chimneys may be obsolete in modern buildings, but they’re crucial habitat for the bird species on the West Coast

smithsonian.com

Larry Schwitters, a fit 70-year-old in black Ray-Ban sunglasses, climbed a narrow, 40-foot ladder to the top of an old brick chimney on an elementary school. It was a sunny day in Monroe, Washington, and heat radiated off the flat, tar roof. Schwitters, uncertain whether or not the extension on the ladder was locking securely, jiggled it warily. Schwitters looked vulnerable so high in the air, even rigged to a climbing rope held by a friend. “Larry takes his life into his hands when he does this,” said the man holding the rope, Jim Rettig, president of a nearby Audubon Society chapter. “No, I take my life in your hands,” Schwitters called down.

Schwitters is a retired science teacher and former mountain climber who no longer thrills to heights. But he needed to repair a microphone he had fitted to the top of the chimney along with a video camera. When it’s working correctly, the equipment records the activity of birds called Vaux’s swifts. Like their cousins the chimney swifts, which live in the Eastern United States, these Western birds gather in huge groups inside old brick chimneys. The sounds and images from the equipment stream live over the Internet. The swift is Schwitters’ idée fixe. He spends at least 30 hours a each week on swift-related projects like this one.

No one knows exactly where Vaux’s (pronounced “vauks”) swifts spend the winter, or the details of their migration route. It’s not even known whether they migrate at night, as most birds do. But we do know the birds need chimneys. Schwitters has discovered that this one at Frank Wagner Elementary School might be the most important chimney in the region—more than 26,000 birds have been counted entering it in one evening.

Four years ago, this unused, 1939 chimney was a candidate for demolition as an earthquake hazard. Countless other old swift-sheltering chimneys, obsolete in buildings with modern heating systems, have already been lost to renovations or collapse. Schwitters and a growing band of others want to uncover more of the swifts’ secrets, and in the process stop more of the birds’ chimney stacks from falling.

On a busy night, the birds would be clinging to the bricks on the inside of the chimney in overlapping layers. But today Schwitters saw only one inside the stack. “Well, hello, birdie,” he piped.

Standing on the roof, I found a dead swift, remarkably intact, and scooped it up. Hold a soft, soot-brown Chaetura vauxi in your hand and you’ll feel how light it is—no heavier than a handful of cotton balls. You’ll also get a sense for what kind of flier it might be—the bird is mostly wings, two scimitar-shaped extensions that give loft to a stubby body and short, squared-off tail.

“They’re some of the most aerial of all birds,” says Charles Collins, a swift researcher and professor emeritus at California State University, Long Beach. “If they’re not feeding young, they’re probably on the wing all day.” In the air, they feed on insects and ballooning baby spiders. The birds’ high-flying ways may be one reason we know so little about this species.

The birds gather in huge numbers in the sky in the evening, swooping and whirling together on those elegant wings, then forming a gyre and plunging into the chimney for the night. “There are prettier birds, like the warblers, or bigger birds, like the great blue heron,” says Rettig. “But just to watch the swifts all together, well, it takes my breath away.”

Vaux’s swifts originally roosted and nested not in chimneys but in the hollow trunks and branches of old or dead trees. But those are few and far between on the modern migration route. Looking south from the Wagner School roof, there’s a bald patch on the foothills of the Cascade mountain range, a clear-cut in a spot where swifts might once have slept over. That’s why chimneys like these have become essential habitat.

Swifts are agile in the air, but not on land. They’re in the family Apodidae, a group of birds that can’t perch or walk—they can only cling. Since around the time of World War II, brick chimneys have been lined with metal or other materials to meet modern fire codes, and Vaux’s can’t use them. Chimneys older than that are generally crumbling, and therefore endangered.

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