The sound starts first, like an overture to a opera. The music is eerie, resembling an enormous chorus of high-pitched, frenetic chittering.
On a September evening, near dusk, thousands of migrating chimney swifts swoop around a square brick industrial chimney in Hampden on a secluded edge of the Jones Falls Valley. It’s a spectacle of sight and sound. Some evening as many as 100 people congregate to watch this semi-annual ornithological exhibition.
The chimney swifts seem to prefer the stout smokestack at the Free State Bookbindery on Elm Avenue in Hampden.
Its owner, Richard Wimbrough Jr., said the bindery employs 18 workers. His clients include the Naval Academy and the University of Maryland. The building is 64,000 square feet on three floors. Free State has been operating here since May 1, 1984.
No one knows when the swifts started calling, but local birding records go back 30 years.
The factory at 3110 Elm was constructed during the summer of 1930. The chimney where the swifts retire nightly stands about 60 feet high and was part of the original plant. Its first owner was the English-American Tailoring Co., a firm that still custom-makes suits and other garments in Westminster. The chimney vented the boiler that produced the steam for heating and the clothing pressing machines.
About the time the tailoring firm was moving in at the onset of the Great Depression, workers were bottling Noxzema skin cream on an adjacent street, Fallscliff Road. That concrete structure has been converted recently into apartments. Some of its residents watch the chimney swifts from its parking lot.
To the east is the old Florence Crittenton Home property, where new three-story rowhouses are being built. The stone mansion at the center of the property, which slopes into the Jones Falls Valley, was the residence of prominent 19th-century mill owner David Carroll.
About 2,000 chimney swifts made their way inside the Free State Bookbindery chimney late this week. They arrived at 7:24 p.m. just as the streetlights were coming on.
Joan Cwi, an ex-president of the Baltimore Bird Club, describes the chimney swifts: "In flight they make continual chittering vocalization. They have speed, agility and superior eyesight and catch insects in flight. They swoop and swirl and seldom fly in a straight line. They fly at 60 miles per hour.
“It is a gregarious species and is seldom seen alone,” she said. “They hunt in groups of two to 20 and migrate in flocks of six to 20. But in May and September, when they migrate, up to several thousand can roost in a large commercial chimney."
Chimney swifts breed along the eastern United States and Canada. In the late summer and early fall, they migrate to South America. In spring they return. The migrating chimney swifts will spend some time in Baltimore on each of their long-distance trips.
The tiny birds use their feet to cling to the sides of the chimney walls. They exit the chimney at dawn and return at dusk.
The Baltimore Bird Club keeps records of the chimney swifts’ fall and spring visits. Not all years do the swifts spend the night at the book bindery. At times, they have chosen the chimney at the Rawlings Conservatory at Druid Hill Park. They also have spent the night at chimneys at the Scottish Rite Temple at Charles and 39th Streets, the Johns Hopkins University security headquarters on Remington Avenue or the St. Michael the Archangel parochial school in Overlea.
“The chimney swifts are aerial insectivores and constantly seek out bugs in the air," Cwi said. "When the temperature changes and the bugs disappear, the chimney swifts are gone.”