Chimney swifts — tiny birds that can eat up to 6,000 insects a day and whose population is in rapid decline — will have two new places to roost in Tarentum.
The migratory birds are expected to arrive in Western Pennsylvania this week from their winter home in South America.
Tarentum Council approved two chimney swift towers for construction, one near the marina under the Tarentum Bridge and one along Bakerstown Road where the Rachel Carson Trail crosses.
The tall structures mimic an actual chimney, climbing several feet into the air. They’re constructed with interior walls that provide for roosting and nesting.
The towers are used by flocks of birds that can reach into the hundreds or thousands, allowing the birds to conserve heat and avoid exposure.
“The towers are great for habitat and they are also a great educational tool because of the graphics on the outside,” said Jim Bonner, president of the borough’s environmental advisory committee and former executive director at Audubon Society of Western Pennsylvania.
He said the tower on Bakerstown Road will include information about the larger Rachel Carson Trail network.
“Chimney swifts are iconic to Pittsburgh,” said Chris Bason, current head of Audubon, headquartered in Fox Chapel. “They migrate here every year to take advantage of the long daytime hours, and we welcome them back.”
The Audubon Society launched the tower project in 2011 with a prototype chimney.
It has since placed more than 150 towers across Allegheny County parks, municipal spaces and public areas. It’s the largest concentration of “purpose-built” chimney swift habitats in the country, Bonner said.
The birds, often described as looking like cigars with wings, Bonner said, originally nested in large hollow trees, caves and cliffsides.
“As settlement occurred, a lot of those things went away,” he said.
The birds adapted and started using house chimneys. But changes in construction — most chimneys are now lined with stainless steel instead of mortar — have caused a rapid decline in available roosting space.
“It’s a serious concern,” Bason said. “This program helps by providing new nesting sites all around the region, and it’s pretty cool that Tarentum is getting two.”
Because chimney swifts aren’t able to perch on a branch like other birds, they like to cling to vertical surfaces using spines on the end of their tail feathers.
While one tower could be used by hundreds of birds during migration, chimney swifts won’t let other birds in while nesting.
Bonner said man-made towers are crucial to regenerating the population, which has declined about 70% over the past five decades, according to the State of the Birds report issued by the North American Bird Conservation Initiative.
Harrison Hills and Deer Lakes Park each have chimney swift towers with educational graphics. There are structures built along the Butler-Freeport Trail, as well.
“People love their little twittering noises and watching them fly into chimneys by the hundreds and thousands,” Bason said. “They’re great for the city because they make the places we love easier to live in because they eat so many bugs.”