Nature Notes: Chimney swifts dine on the nastiest of bugs
Meet the chimney swift, a feathered friend that I’d like to have flying above my backyard any time.
Why? These five-inch-long, swallow-like birds, with slender, foot-long wings, beautifully designed for speed, can mow down mosquitoes, flying ants, termites and May flies — pests that none of us like — at astonishing rates.
“One pair of adult chimney swifts and their noisy young,” writes the website wildbirdhabitatstore.com, “will consume over 12,000 flying insects every day.”
Maggie Jones, an accomplished birder and former executive director of the Denison Pequotsepos Nature Center of Mystic, agreed.
“Consider yourself fortunate if these long-distance migrant birds happen to spend the late spring and summer in your chimney,” she said, meaning birds like these will almost certainly lighten the load of insects that may be flying near your home.
“Locally, chimney swifts can be seen whirling about over towns and cities, like Mystic, New London, and Westerly,” Jones said, adding, “They spend more time in flight, feeding, courting, drinking, bathing, and gathering nest materials than any other land birds.”
Because of their aerial lifestyle, ornithologists do not know much about the life history of chimney swifts. And when they stop flying at dusk, these super-fast bug chasers quickly spiral out of the sky and down into dark, hard-to-reach places, like chimneys, hollow trees or caves to roost or nest, making it difficult for scientists to study them.
In 1824, for example, while traveling in Kentucky, John James Audubon witnessed a large flock of chimney swifts end their day by funneling into a hollow sycamore tree. Undeterred by the swifts’ inaccessibility, Audubon, the intrepid birder that he was, took matters into his own hands. Later that night, he writes in his journal, Audubon returned to the tree, carefully cut a hole in it, climbed in with a lantern and estimated he saw 9,000 chimney swifts, clinging to the insides of the tree.
Also interesting about chimney swifts, they kept the birding world guessing where they wintered, until 1927, when a band of Peruvian Indians discovered huge flocks roosting in the Upper Amazon basin.
We do know, however, chimney swifts breed throughout most of the eastern half of the U.S., typically arriving in New England by late March to mid-April and departing for South America by early October.
Nesting starts in May, with both males and females building a half saucer-like nest made of tiny twigs, glued to the walls of caves or chimneys with their own sticky saliva. The female then lays three to five eggs, and the chicks hatch in about 18-19 days.
Sadly, chimney swift numbers have declined precipitously (more than 70%) since the late 1960s, Jones said.
“When homeowners cap or clean chimneys during the nesting season, they inadvertently destroy nests and kill young,” Jones said. “Keeping the damper closed will prevent young from accidentally falling into your fireplace.”
Finally, Jones said chimney swifts are protected by federal law under the Migratory Bird Act, so it is illegal to interfere with their nests and activities. But she adds, “Why would anyone want to disturb these beneficial insect eaters?”
Bill Hobbs lives in Stonington. He can be reached at email@example.com.
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