If you’ve been in the city of Burlington around sunset this past winter, you might have found yourself in a Hitchcock film. Eerily large flocks — or murders — of crows dominate downtown areas, flocking from one perching location to the next in massive swarms estimated to contain between 2,500 and 3,000 crows.
It’s not uncommon for these gatherings of crows to draw flocks of curious humans out onto the city sidewalks, snapping photos of the treetops as the sun begins to set.
Naturalists say there are a few different theories about this bird behavior, but Burlington's mantel as a crow hot spot is likely due to a combination of factors — the Queen City's lower elevation, proximity to the lake, the comfort that city light provides, and that by flocking together the crows can work together to find food.
"When winter comes, all the leaves fall off, the insects start dying down, and there’s much fewer food resources," said Jacob Crawford, an AmeriCorps member specializing in community science serving at Vermont Audubon. "So, that’s when birds need to start working together to help them find food, and that’s one reason why crows flock together."
More from Outdoor Radio: A Mega-Roost Of Crows
It's a change, Crawford says, from regular crow behavior. In the spring and summer when food is abundant, crows can be found in pairs or even solo.
Another hypothesis involves body heat. On colder nights, the crows band together, squeezing hundreds of birds roosting in just a handful of trees.
“There are some studies that are thinking that it’s actually providing a little bit of thermal cover for the crows," Crawford says. "It’s like penguins huddling together, but instead, you’re in the trees.”
It’s like penguins huddling together, but instead, you’re in the trees.Jacob Crawford, an AmeriCorps member specializing in community science serving at Vermont Audubon
There’s also strength in numbers. Crows are common prey to larger birds, namely the great horned owl. It’s the largest and heaviest of its species, it's essentially the great white shark of owls. But with a large flock of crows, these predators tend to keep their distance.
The pack life seems to be quite the draw. Crawford says in recent years, a surprise visitor has started to join the party.
“Most of the crows in the crow roost in Burlington are American crows, and they are very much native to the Vermont landscape," Crawford says. “But we have a newcomer to the scene, and that’s the fish crow.”
Fish crows began popping up in Vermont in the late 1990s and early 2000s. Today, there's an estimated 30 to 40 fish crows in the area. The Burlington clan represents one of the northernmost breeding populations of fish crows.
Fish and American crows look nearly identical, but if you listen closely to a downtown roost, you might be able to pick them apart.
The American crow has a loud and classic ‘caw’ while the fish crow’s call is more nasally with a muted pitch.
In folklore across cultures, crows take on the roles of tricksters, omens of change, and messengers between the dead and the living. Crawford describes them to be incredibly intelligent creatures, great problem solvers, with impressive memories and hyper-observant eyes. He says when a crow looks at you, it really looks at you.
As the temperatures begin to warm, the Burlington roost will slowly break down, and many crows will keep to their daytime address in Charlotte or Shelburne.
But Crawford says there’s even more to look forward to.
“Spring migration is one of the most amazing bird spectacles, in my mind, just because the landscape is filled with song, all these birds are in their beautiful breeding plumage, they’re all freshly brightly colored and flashy," he says.
In May, Crawford says you can spot birds you wouldn’t normally see. The marshy shores of Lake Champlain and its surrounding areas make for a prime pit stop for birds migrating north to summer in Canada. Some feed for a matter of days or weeks before continuing northward.
Crawford describes them as "a wave of birds that hits Vermont all May long." That includes red-winged blackbirds, brown-headed cowbirds and common grackles among them.
You can think of them like birds that won’t stick around through summer, the vacationers passing through, and the migrators towing winter suitcases in their beaks.
This story is a collaboration between Vermont Public and the Community News Service. The Community News Service is a student-powered partnership between the University of Vermont’s Reporting & Documentary Storytelling program and community newspapers across Vermont.
