The Conowingo Dam on the Susquehanna River in Maryland is a 4,648 foot long power plant with 11 turbines capable of producing 572 MW of electricity when running at peak capacity. Also known as the Conowingo Hydroelectric Generating Station, when it was constructed in 1928 it was the second largest hydroelectric project in the United States, bested only by Niagara Falls. With a maximum height of 94 feet, it consists of four distinct…

“WAIT!” you’re saying. “This is supposed to be a nature blog! Why are we talking about a DAM? What could possibly be of interest to us there?”

Well…

This:

And maybe this:

And even this:

Five Bald Eagles in one shot? (And there’s a sixth in the picture somewhere. Can you find it?) Yes, folks, this was taken just downstream of Conowingo Dam, and those eagles represent maybe 5% of the eagles present there on the Saturday after Thanksgiving. 154, by one very approximate count. Every fall, in November and December, eagles gather downstream of the dam in large numbers. 50, 100, sometimes even more.

“What for?” you ask. Fish, of course. When the turbines are running, fish get sucked through the intake tubes and are discharged below the dam, stunned or dead. Easy picking for piscivorous (fish-eating) birds like Bald Eagles.

“Why late fall?” you ask. The dam only operates when electricity demand is high. In other words, late fall and winter. By January, most eagles are returning to their nesting sites to raise a new family, and they will be tied to those sites through the summer. But in the fall, they are free to go where the fish are, and in my area, that’s Conowingo.

Birders in the know flock to Conowingo to watch the spectacle. Photographers, too. All the cold weather gear was necessary; it was 25 degrees. Definitely not for the faint of circulation. I lost my feet after the first hour.

You have to be prepared to wait a long time; it’s not non-stop action. Even though several turbines were running when I arrived at 8 AM, the eagles were very quiet, content to perch on trees or rocks across the river and wait. One or two were obliging enough to perch in trees directly behind us and pose. Or maybe they were amusing themselves watching all the stupid humans shiver.

The wait paid off after more than an hour when more turbines started up. Fifteen minutes later it was like someone had thrown a switch: suddenly it was a Bald Eagle Bonanza. There were eagles catching fish. Eagles dropping fish. Eagles fighting over fish. Eagles stealing fish from other eagles. Sometimes I didn’t know which bird to follow. Other times they flew so close overhead I couldn’t zoom out fast enough.

Bald Eagle diving on a fish in the Susquehanna River. Note the four other Eagles in the tree in the background, waiting for their chance.

           Approach                             Landing gear down                 In-flight food service.

And away we go with dinner.

Conservation Piece: This bird looks worried. About the American shad, perhaps?  This migratory fish lives in the ocean, but returns to freshwater rivers like the Susquehanna to spawn, usually during the spring or summer. Their numbers have been seriously depleted by fishing, water pollution – and the construction of dams like Conowingo, which block passage to their spawning grounds. Exelon, who operates the dam, has been working to restore the American shad to the Susquehanna River through the operation of two fish lifts at Conowingo Dam. The company has also built a Fisherman’s Park at the foot of the dam, for fishing, bird-watching, and photography. They even run an annual Bald Eagle Photo Contest!

Coming up: The Kids’ Table