The chimney swifts appear as the edges of the sky turn purple, whirling around the tall brick chimney. With each moment, more birds wheel closer to the former bookbindery in Hampden, swooping through the darkening air.

Soon more than a thousand birds have assembled in the sky above the chimney, trilling to each other as they prepare to rest for the night during their seasonal migration from Canada to South America. Then, as if following instructions, the swifts form a ring in the air. The circle of birds spins faster until one by one, the birds plunge into the chimney. Two birds linger outside before they swoop down into the chimney just as the last glimmers of sunlight fade.

“I think of it as a dance and every night there is a different dance,” said retired social worker Carol Schreter, as she watched the chimney swifts one evening last week with fellow members of the Baltimore Bird Club.

For decades, bird lovers have flocked to watch the swifts as they roost in the century-old chimney near the Jones Falls as part of their autumn journey south. But the birds may soon lose their roost; the bookbindery is slated to be demolished as part of a planned redevelopment of the property.

“The idea that this could be coming down is devastating,” said Alice Greely-Nelson, a Baltimore Bird Club member who has been counting the swifts each September for the past three decades. Already, the birds have lost another important roost, a chimney at the nearby Mill No. 1 building, which was partially capped when the building was redeveloped several years ago, club members said.

Representatives of the Segall Group, the commercial real estate developer that purchased the bookbindery, did not respond to repeated requests for comment. But Councilwoman Odette Ramos, whose district includes Hampden, and Benn Ray, president of the Hampden Village Merchants Association, said they were told Segall plans to demolish the bookbindery — including the chimney — and construct 160 luxury apartments on the site.

Architect Peter Fillat, who shared the plans with Ramos, Ray and others on Segall’s behalf, also did not respond to several requests for comment.

(L to R) Libby Erickson, Alice Greely-Nelson and husband David Nelson gather to watch the chimney swifts gather for the night  in Hampden's old bookbindery as they journey from Canada to South America. This year, could be the last as the building has been purchased and possibly slated for demolition.

Ramos said she was dismayed by the project, which would bring an influx of residents to a corner of Hampden where developers recently constructed 19 new townhomes on the grounds of the former Crittenton mansion. Some of the townhomes face the bookbindery. The nearby Fox Building was also recently converted into apartments.

“I have to tell you, I’m really mad about this,” Ramos said of the plans for the bookbindery. “Hampden is oversaturated with development. People are trying to add as many units as possible in a tiny area. Why are developers only looking to develop in white neighborhoods? Why aren’t developers looking to develop in our Black neighborhoods? I’m proud to represent Hampden, but I’m also proud to represent Coldstream Homestead Montebello and Darley Park and many other neighborhoods.”

Ramos said the property is zoned for industrial mixed-use, which would allow for the construction of apartments, and there is currently no historical designation to protect the property. The developer has yet to present detailed designs for the site, Ramos said, and any plan would have to go through standard city vetting procedures.

Ray, the neighborhood merchant’s association president and co-owner of Atomic Books, said his organization had not taken a stand on the project yet. But he also said that as a city resident and business owner, he opposed the creation of luxury apartments. “I don’t think our neighborhood or Baltimore really needs more luxury apartments. We need affordable housing,” he said in an email.

“The chimney swifts have long been a local delight — and losing them to luxury apartments no one who lives here is asking for — well, we as a community are losing a beloved public, common attraction for private profit,” Ray said.

Chimney swifts are protected under the federal Migratory Bird Treaty Act, which makes it illegal to kill the birds and destroy or move their nests or eggs without a special permit, said Paul Kyle, a project manager with the Chimney Swift Conservation Association. They are classified as “vulnerable” on the International Union for Conservation of Nature’s Red List of Threatened Species. Their numbers have declined rapidly in recent years, Kyle said.

Greely-Nelson’s meticulous records for the Baltimore Bird Club show that the numbers of swifts roosting in the bookbindery chimney have plummeted over the 36 years she has been tracking them. In 2003, club members recorded more than 7,400 birds roosting in the chimney on one night. This year, the highest count came on Tuesday, when 2,540 birds headed into the chimney, Greely-Nelson said.

(L to R) Libby Erickson, Alice Greely-Nelson and husband David Nelson gather to watch the chimney swifts gather for the night  in Hampden's old bookbindery as they journey from Canada to South America. This year, could be the last as the building has been purchased and possibly slated for demolition.

The birds evolved to sleep in hollow trees or caves, but in recent centuries, as forests were cut down, they adapted to roost in chimneys. Their unique bodies make them unable to perch on branches like most birds. They are shaped like boomerangs, with egg-shaped heads and narrow tails. The pointy spines of their tail feathers enable them to prop themselves up when clinging to a vertical surface, such as a chimney. At dawn, the birds crawl back up the chimney and rush into the air.

Chimney swifts fly with their beaks open, startling insects into their wide mouths as they swoop through the air. They are “completely benign and beneficial birds,” said Kyle of the Chimney Swift Conservation Association. Each bird eats thousands of small insects, such as gnats, mosquitoes, flying termites and flies each day, he said. “We should all be happy to have them in our skies and do whatever we can to protect them and their nesting and roosting sites,” he said.

It is unclear how chimney swifts choose their roosting sites, but once a flock finds a spot, they return for many generations, he said.

“Demolition of the old bookbindery … would have a tragic impact on the birds that use it,” Kyle said. “It would also be a great loss to the community which has monitored and cherished the birds that use it for as long as I can remember. I believe that this particular chimney is host to one of the largest Chimney Swift roosts in that part of the country.”

Other popular spots for migrating chimney swifts in Baltimore include the Druid Hill Park Conservatory, Roland Park Country School and St. Michael the Archangel Church in Overlea, according to the Baltimore Bird Club.

If the bookbindery chimney is demolished, the birds, already weary from their journey, will be forced to track down a new roosting place — if a suitable location even exists. “Migration is already such a taxing event for them,” said Libby Errickson of Hampden, the Baltimore Bird Club’s citizen science chair, pointing out that some birds will inevitably die without the roost.

Schreter, a retired social worker from Mount Washington, said she is continually amazed by the birds’ interactions. “This is a social phenomenon that is amazing. They fly independently all day and then come together at night.”

For Greely-Nelson, who lives in nearby Stone Hill, the birds’ chittering calls are a “reassuring sound of summer.”

“There’s no other bird that gathers in such great numbers in a chimney,” she said. “It’s magical to me.”

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