Animal of the Issue: Chimney Swifts

A group of Chimney Swifts can be called a “flock,” a “box,” a “swoop,” or a “screaming frenzy.” Photo Courtesy / John Schwarz
A group of Chimney Swifts can be called a “flock,” a “box,” a “swoop,” or a “screaming frenzy.” Photo Courtesy / John Schwarz
A group of Chimney Swifts can be called a “flock,” a “box,” a “swoop,” or a “screaming frenzy.”
Photo Courtesy / John Schwarz

By Briana Magistro
SC Staff Writer

Imagine walking around campus and seeing hundreds of flying animals circling the big smoke stack on the Facilities Management Complex. This is what Thomas Counterman, a plumber on campus, saw one night at work.

“It was right at dusk, and I saw what I thought were bats flying out of the main chimney of the facilities plant. At last two or three hundred circling the top of the chimney,” Counterman said.

He continued, “My partner and I, Matt, walked down toward the chimney and then we realized they were birds.”

He decided to talk to Dr. Master, the ornithologist on campus, about what he saw.

“The following night, I made it a point, right at dusk, to watch them come back again. I thought it was a bat fly-out, and here it was a bird fly-in. They were coming to roost in the chimney. It was almost like a scene in a crazy horror movie! I didn’t realize there was anything that could live in a chimney like that!”

Dr. Master was able to identify these birds, called Chimney Swifts, which roost on campus.

Chimney Swifts are in a group of birds called aerial insectivores, which gather their insect prey while in flight. Barn swallows and whippoorwills are other examples of birds in this group.

“There are about four or five of these birds that live around here, and the Chimney Swift may be the most common,” Dr. Master pointed out.

The Swift’s main food source comes primarily from beetles and flies, and they feed a few hundred meters off the ground.

They are most common above cities, due to the air currents, which lift insects high into the air. “If you look at maps of Pennsylvania, concentrations are located mostly above cities,” he commented.

Chimney Swifts typically roost inside chimneys, hence the name Chimney Swift, which makes it normal for them to be seen in cities.

“The original resting sites were things like caves, or abandoned woodpecker holes. By 1770, they were virtually all roosting in chimneys,” Dr. Master said.

He continued, “This is a species that benefitted from settlement in North America. They almost exclusively nest in chimneys, cisterns, and smoke stacks.”

Although Chimney Swifts originally benefitted from human development, new agricultural techniques may be causing the start of a decline.

“The thought is that insecticides are reducing insect populations,” Dr. Master stated about the species’ decline. It is possible that the development of wide-use insecticides, which were produced in the 1970s, may only have just begun affecting the bird’s population.

This same decline has also been documented in other aerial insectivores.

Another reason for their decline is the disappearance of chimneys in modern architecture.

“There’s been a change in heating from coal and oil to electric, which is more efficient,” Dr. Master said.

Chimney Swifts are one of the smallest and lightest birds of its group. They are most closely related to hummingbirds. The bend of the wing is close to the body, so that the birds can hover.

“It also increases their speed,” Dr. Master added.

In early May, Swifts arrive in our area, as well as on the entire eastern US, after having traveled across Mexico from their winter roosts in South America.

“Males and females build the nest together. They go in and hang in a spot together. This becomes the nest site. They build a nest with tiny twigs that they apparently break off by flying through branches,” Dr. Master explained.

A typical Chimney Swift nest contains four to five eggs.

On their way down to South America in the winter, Chimney Swifts have been known to venture right across the Gulf of Mexico.

When asked about the Swifts’ natural predators, Dr. Master said, “They’re pretty fast!” Some hawks, like the Sharp-Shinned Hawk, and owls, some of which we have on campus, are natural predators.

If you are out around dusk on campus, keep a lookout for the population of Chimney Swifts returning to their nests in the stacks.

Before long, they will make their big trip to South America, and we won’t see them again until the spring.

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