18 December 2024

Winter crows are incredibly persistent. Year after year they return in large numbers to the same city, even if the city harasses them. Some cities harass their winter crows, some celebrate them. This is a Tale of Two Cities from the winter crows’ perspective — Rochester, New York and Lawrence, Massachusetts.

But First. Large roosts of 10,000 to 100,000 birds is normal behavior for crows. Dr. Douglas Wacker described why at his Olympic Peninsula Audubon presentation in Nov 2024 (see below, parentheses added). Large Crow Roosts have:

• Safety in numbers (low odds of predation)
• Early warning system (many eyes on the lookout)
• Thermoregulation (warmth)
• Exploit a resource (we all share)
• Share information (catch up with your friends).

Once crows find a good location, described here, they all come together in the same place.

Thousands of crows come to Rochester, New York every winter where they prefer to roost in Washington Square with its well lit, mature trees.

The city doesn’t like the crow mess so every year they hire USDA to harass the crows for three nights. USDA’s goal is to “break up the roost” into smaller units. Rochester made the New York Times this week for their harassment techniques.

From the crows’ perspective, smaller units won’t provide safety in numbers so the crows will reconvene somewhere. But where? Will the new location cause trouble, too?

Rochester could choose a middle way to solve their problem. In 2010 Penn State picked a location away from people where they wanted the crows to roost. Knowing that crows want to sleep with the lights on, they floodlit a remote set of trees and harassed the crows away from the center of campus. The crows moved to the floodlit site. Ta Dah! Read more at Penn State relocates its winter crows.

Meanwhile thousands of crows visit Lawrence, Massachusetts every winter but as far as I can tell they have never been harassed there. Instead the roost is celebrated as a tourist attraction, described on the Winter Crow Roost website and YouTube channel.

Nov. 18, 2024: Join us for an unforgettable evening on Crow Patrol under clear skies (55°F, NW winds at 15 mph) as we explore the Merrimack River staging area east of Rt. 495. Witness the incredible sight of American and Fish Crows vocalizing and converging into tree tops in a wild, dramatic display at the east end of Island Street.

Don’t miss this breathtaking show of nature in action! Watch now and share with friends who love the beauty and mystery of wildlife.

— description of video at Winter Crow Roost on YouTube

So from the crows’ perspective, you’d rather choose Lawrence, MA over Rochester, NY.

(*) p.s. Rochester’s crows are never going to switch to Lawrence MA. They come from different parts of the continent: Lawrence = Atlantic coast. Rochester = interior and south of Hudson Bay.