Feb. 4, 2026 under clear skies, wind W 5mPH, temp 29F; sunset time 5:02PM

Another memorable winter evening unfolded along the Merrimack River corridor as crows moved through familiar staging areas and built steadily toward an overnight roost. The patterns were classic, dynamic, and endlessly engaging. TheCrow Patrol began with a slow progression along Merrimack Street, continuing down to the O’Leary Bridge on Broadway. Large numbers of arriving crows gathered in trees near the south end of the bridge, creating an immediate sense of energy. Vocalizations were loud and persistent, with birds calling continuously as new arrivals dropped in, reshuffled, and repositioned in nearby trees.

Just west of the dam, huge numbers of crows assembled on the river ice, offering outstanding views from the bridge. As wave after wave of incoming flight streams arrived, these ice-bound groupings expanded dramatically. Birds lifted off in short bursts, circled, and settled again, creating a constantly shifting mosaic of movement against the pale winter ice.

As darkness settled in, the focus shifted to the south side. Crows began perching in long lines of trees along the south side of the Merrimack River, particularly behind the Lawrence Experiment Station. The Lawrence Experiment Station was a pioneer engineering laboratory dedicated to research on the treatment of water supply, sewage and industrial waste and has been recognized nationally and internationally for contributions to the environmental engineering field. Activity remained high, with steady vocalizations, frequent short flights, and continual settling as birds tested roosting spots.

The overnight roost then filled in rapidly along this same stretch of riverside trees, extending from Broadway up toward Rowe Street. Numbers increased quickly as late arrivals poured in, and the line of trees became densely packed with perched birds as seen in the dynamic thermal aerial image below. Even as movement gradually slowed, reshuffling and calling continued well into the evening. Another dazzling winter crow show along the Merrimack, rich in sound, motion, and scale.

For the 2025 National Audubon Christmas Bird Count (CBC) for the Andover Circle (MAAN), the dedicated crow roost count totaled 14,025 crows, including both American Crows and Fish Crows. By comparison, the Andover Circle crow count was 12,550 in 2024 and 11,600 in 2023. Many thanks to Mark Morroni and Donna Cooper, who coordinated and compiled the Andover Circle CBC this year. Craig serves as the designated sector leader for the Lawrence winter crow roost count.

The counting methods developed by the Crow Patrol for the Lawrence roost were formally reviewed and approved in January 2021 following a detailed evaluation of field notes, images, and group discussion with Wayne Petersen, New England Regional Editor for the CBC, with full support from Geoff LeBaron, National Director of the CBC, and Donna Cooper as local compiler. After this comprehensive review, the 2020 CBC American Crow count was finalized at 15,200, a figure fully supported by field documentation and consistent with long-term observations by experienced local birders.

Building on guidance from the National CBC leadership, we now use enhanced, field-based counting methods tailored to large winter crow roosts. These include multiple direct block counts of birds in flight, during staging, and once perched, conducted entirely on foot around the roost. Counts are later cross-checked using still images and video, supported by modified open-source counting software. This multi-layered approach significantly improves accuracy and repeatability. A detailed overview of these methods is available in the Winter Crow Roost Counting Guide (PDF) on the main page.

All images are captured using professional low-light mirrorless camera systems and fast-aperture lenses, allowing for reliable documentation under the very challenging lighting conditions at dusk and after dark typical of winter crow roosts.