July 30, 2013
BELGIUM - That "smoke" pouring into brick chimneys in coming weeks isn't an optical illusion but likely hundreds of native chimney swifts roosting for the night and gathering strength and numbers before they migrate south.
Wisconsin bird experts are asking homeowners, bird watchers and others to help count the birds and report where they see them to provide vital information on a declining, unique species.
"Chimney swifts are an important species in Wisconsin because they help keep flying insect populations in check," says Kim Grveles, Department of Natural Resources assistant ornithologist and a member of the Wisconsin Chimney Swift Working Group. "We need citizens' help in counting the birds near them, and in reporting that information to us so we can better understand and take steps to reverse the decline of chimney swifts."
"You don't have to be an experienced birder or trained researcher to enjoy the evening acrobatic displays of the swift," says Nancy Nabak, co-chair of Green Bay's Swift Night Out program and member of the Wisconsin Chimney Swift Working Group. "The sight of dozens or hundreds or, in some cases, thousands of chimney swifts going to roost for the night in chimneys can be an exhilarating spectacle."
Last year, 60 volunteers helped identify 72 sites, with the largest roost found at Cherokee Middle School in Madison, where more than 2,800 swifts were tallied. Aldo Leopold School in Green Bay, St. Norbert Abbey in DePere, and Geneva Lake Museum in Lake Geneva are sites of other large roosts.
Video footage of chimney swifts at Cherokee Middle School in Madison by Dane County's Four Lakes Wildlife Center.]
Chimney swifts breed and nest in eastern North America and migrate to South America in the fall. Their populations are declining in their range and in 2009 Canada listed them as a threatened species. The Wisconsin Chimney Swift Working Group formed in 2012 to help identify and conduct research and take steps necessary to halt the species' decline, says Bill Mueller, an ornithologist with the Western Great Lakes Bird & Bat Observatory in Belgium and a member of the working group.
Before European settlement, the birds nested in old-growth forests. As such forests disappeared, the birds discovered brick chimneys served as an easy and abundant replacement, Mueller said. Brick chimneys work well for the birds because the chimneys provide enclosed areas with a rough, vertical surface the birds can cling to. Unlike most birds, chimney swifts do not sit on perches like a branch but must use their long claws to cling to vertical surfaces.
The decline of brick chimneys and changes in chimney design in more recent decades have decreased the available nest sites and are believed to be one main reason behind chimney swifts' dropping numbers, Mueller says. "A lot of people are capping their brick chimneys these days, and that's one of the things driving the bird's decline," he says.
Mueller and other experts also want to conduct more research on the insects chimney swifts eat to better understand how changes in their populations might be affecting chimney swifts and other "aerial insectivores" such as whippoorwills and swallows.
Chimney swifts have slender bodies, very long, narrow, curved wings and short, tapered tails. They fly rapidly, with nearly constant wing beats, often twisting from side to side and banking erratically. They often give a distinctive, high chattering call while they fly, Mueller says.
"A lot of folks see and hear them at night and don't realize they are birds," he says. "They think they are bats."
Because chimney swifts congregate in communal roosts before migrating in late summer/fall, it's relatively easy to count them. Here's how to count:
More information about chimney swifts and how to help protect them can be found on the Wisconsin Chimney Swift Working Group webpage. wisconsin-chimney-swift-working-group (exit DNR).
FOR MORE INFORMATION CONTACT: Kim Grveles, DNR, 608-264-8594; Bill Mueller, Western Great Lakes Bird & Bat Observatory, 414-698-9108