Sunday, November 8, 2009

Chimney Swifts and Sweeps

Smoke is swirling out of chimneys on these chilly November mornings. Chopped and split firewood is neatly stacked in many yards. Many of our songbirds have migrated south. This includes the chimney swift, which technically is not a "songbird" of the order Passeriformes, but instead it is, well, in the order of birds with small legs -- the hummingbirds and swifts, or Apodiformes.

Chimneys rather resemble large hollow trees that chimney swifts nested in before chimneys were invented. Obviously the bird was named after bricks and mortar arrived on the scene. After our eastern forests were cleared for pasture and crops, big old trees were no longer available to nesting swifts. Clearly adaptable birds, swifts took to nesting and roosting in chimneys.

Often called "cigars with wings," chimney swifts are fast fliers, snatching insects on the wing with their small, broad bill and wide gape. Swifts do not perch like the somewhat look-alike swallows. Instead they cling to the sides of chimneys, tree hollows, barns and silos, and cliffs. Mostly they fly on their curved, stiff wings, while emitting a high-pitched rapid twitter.

Adult swifts store captured insects in an expandable pouch in their esophagus. Back at the nest they regurgitate the food to their young. Both adults help build a shallow, half saucer-shaped nest made of twigs that they snap from trees as they fly by. The nest is cemented together will their sticky saliva.

My first experience with a chimney sweep (many years ago) was Bert in Mary Poppins dancing on rooftops and singing "chim chim cher ee." I had not thought much about chimney sweeping since then, until we moved to New Hampshire, and met the Seacoast Sweep, our friend and neighbor up the road. Also known as Phil of the Mitchell family, brother of Alan (see story on Homesteading Woodworking School and skunks).

Chimney cleaning is important for swifts and humans, especially to remove any buildup of creosote. That is where the chimney sweep comes in. Phil is a member of the National Chimney Sweep Guild. Visit their website and you will see they have a section on chimney swifts, including a nice photo of a nest inside a chimney. That is cool and essential since chimney swifts are protected by the Migratory Bird Treaty Act; care is needed when cleaning chimneys with nesting swifts.

The chimney swift flies over 6000 miles round trip every year, from the eastern United States to its wintering grounds in Peru. In late summer and early fall swifts congregate in traditional stopover spots to buildup fat reserves before their long journey. Sometimes a single, large chimney hosts thousands of swifts on migration. This is the case for an elementary school in Portland, Oregon, which now attracts hundreds of people who pull up chairs to watch the Vaux's swifts return to this roost at dusk.

The Driftwood Wildlife Association in Texas hosts a great website on chimney swifts. There you can learn about "being a good chimney swift landlord" and enjoying a "swift night out." Suitable swift chimneys are those made of stone, brick, or masonry with mortared joints. These provide enough texture for swifts to cling to the walls. The new metal chimneys are too slippery -- these should be capped to prevent birds and other animals from entering. Talk with your local chimney sweep about ways to make your mortared chimney safe for swifts and functional for humans. Also, don't forget about keeping large, old trees. Perhaps as trees reclaim the land and grow older, chimney swifts will switch back to hollow trees.

Until spring, when the swifts return, snuggle up to the wood stove (or radiator). After a long winter, the return of the twittering, sooty-colored swifts will be a welcome sight.

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