Thermal & Infrared Reveal!

Dec. 20, 2025 under mostly clear skies, wind W at 5MPH, temp 36F; sunset time 4:13PM

The first stop on this year’s Christmas Bird Count Crow Patrol brought us to the southern shore of the Merrimack River, just east of the Route 495 bridge, to watch the early staging unfold. About ten minutes after sunset, the first incoming flight streams appeared from downriver, announcing their arrival with loud, boisterous vocalizations. Long, elegant strands of crows crossed the river and began dropping into the trees, marking the quiet transformation of this stretch of river into an overnight roost.

As the light continued to fade, numbers built quickly in this same secondary roost location. Crows poured into the trees on the north side of the river, landing, shuffling, and settling as branch after branch filled in. What began as scattered silhouettes soon became dense clusters, each arrival adding to the growing sense of anticipation and energy in the roost.

Incoming flight streams continued in what felt like an almost endless series of waves. From the southeast, both thick and thin lines of crows advanced steadily over the Merrimack River, threading their way toward the roost trees. Watching these successive waves arrive was a powerful reminder of the scale and coordination involved in a winter crow roost.

At intervals, the steady flow gave way to bursts of swirling flight overhead. Raucous vocalizations filled the sky as groups lifted, circled, and resettled, creating moments of dazzling motion against the darkening backdrop. These brief eruptions of activity, occurring after arrival at the roost, are a normal and fascinating part of the settling-in process before nightfall finally takes hold.

About fifty minutes after sunset, we moved west to the primary overnight roost near the brick New Balance factory building. From the Duck Bridge, looking west-southwest, the view revealed crows well settled into the riverside trees along the Merrimack. Soft ambient lighting from the building reflected off the water and branches, highlighting the quiet order that follows the earlier chaos.

The evening concluded with a final aerial perspective over the primary roost, captured using special low-light settings. Looking down the line of riverside trees, the full scope of the roost came into focus with treetops and branches thoroughly occupied, with crows spaced in remarkably even, equidistant positions. It was a striking and satisfying end to a night of dazzling action—an unforgettable way to experience the 2025 Christmas Bird Count.

From a CBC perspective, evenings like this also provide an opportunity to pair careful block counting in the field with later cross-checks using still photos and video footage, helping to refine estimates and better appreciate the true scale of these remarkable winter roosts.

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.