April 22, 2024: under clear skies, wind NW 6MPH, temp 52F; sunset 7:35PM

Out on Crow Patrol after being away. The overnight roost has shifted back to the north side of the New Balance building along the Merrimack River. The same seasonal shift was noted in my eBird posting on 4.12.23 last spring. The remaining Crows tend to move back and remain in this location over the summer months as the numbers fall off further. These tend to be younger Fish and American Crows. The Fish Crows are not cooperative breeders, so they refrain from being helpers around the nest. About 40% of the 116 species in the crow family (including jays, magpies and nutcrackers) are cooperative breeders. It’s estimated that across all bird species, only about 9% are cooperative breeders.

In an effort to take in all the action, made my way out to the middle of the Duck Bridge, and remained in place on the west side of the bridge. By 8 minutes after sunset time, Crows were flying in and lining up along the roof edges on both side of the Merrimack River. This image shows the Mill240 building, the Pacific Mills stack, the Verizon Tower, and the gorgeous sunset sky colors over the river.

About 10 minutes past sunset, a continuous flight stream of Crows was seen coming in from downriver to the east, over the bridge and onto the rooftops by the extended roost area. This image below shows the flight stream coming as far back as the Marston Medical building and beyond!

By 30 minutes past sunset time, the roost trees along the Merrimack River started to fill up with Crows. The largest concentration was towards the west end of the New Balance building and behind the National Grid substation. This image was also captured from the Duck Bridge.

A few minutes later, due to a very loud truck rumbling southbound over the bridge, the Crows lifted off in flight out over the river. These flight bursts are always fascinating and entertaining. The Crows will often loop out from the roost and return to the trees moments later. As the season winds down, still a nice night out!

For the 2023 Audubon Christmas Bird Count (CBC) for the Andover Circle, this separate Crow Count was 11,600 total Crows, including American Crows and Fish Crows. In 2022, the CBC Andover Circle Crow Count was 13,750. Many thanks to Donna Cooper who coordinates and compiles the Andover Circle each year!

Note on counts/estimates: we are now using improved methods for counting the large number of Crows while streaming, staging, and in the roost. For all images, we use both a modified open source counting software program, as well as a hand count approach, while outside next to the roost, to carefully document our observations and to significantly increase reliability and accuracy of the presented numbers. Please refer to our new roost counting guide on main page.

The Canon mirrorless cameras with the RF 50mm f/1.2 lens and the RF 28-70mm F2 excel in low-light conditions, blending versatile focal lengths with an ultra-wide aperture. Both focal lengths work extremely well in very low light conditions, while the f/1.2  and F2 aperture settings ensure exceptional performance in low light conditions, offering stunning clear, and aesthetically pleasing images, making them ideal for the challenging very low light conditions around the overnight roost.

Remember to check out the latest Crow Patrol Podcast with John Macone (Merrimack River Watershed Council): wintercrowroost.com/podcast/

Photo gear used for most outings:

Canon EOS 80D with Canon EF-S 18-135mm f/3.5-5.6 IS 

Canon EOS 80D with Canon EF-S 18-135mm f/3.5-5.6 IS (Infrared)     

Canon EOS R6 Mirrorless with Canon RF 28-70 f/2 L IS USM 

Canon EOS R6 II Mirrorless with Canon RF 50 f/1.2 L USM 

Sony AX700 4K HDR Camcorder

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