Conowingo Dam

On the lower Susquehanna River, only 10 miles upstream from the Chesapeake Bay, stands the Conowingo Hydroelectric Generating Station. The Exelon Power Company owns the masonry gravity dam, which has been operating since 1928. At the time of its opening, the dam was second in size only to the hydroelectric dam at New York's Niagara Falls. 

At 94-feet tall and 4,648-feet wide, the Conowingo Dam is four times wider than the Hoover Dam. It spans the Susquehanna connecting Cecil and Harford Counties in northern Maryland. As the state's largest producer of renewable energy, the dam has 11 turbines that can generate 572 megawatts of electricity. Hailed as a stunning feat of engineering at the time of its construction, the Conowingo is now equally famous as a busy feeding ground for birds–especially American bald eagles.

The dam creates unique feeding opportunities for bald eagles and other fishing birds. The turbines' intake valves suck water and fish through the dam, often stunning or killing the fish and depositing them downstream for easy capture. Additionally, migrating fish attempting to travel upriver get stuck below the dam and gather in its tailrace. During the winter months, fish remain readily accessible to the birds because the water flowing through the dam does not freeze. The dam's tailrace is a smorgasbord that attracts feeding birds from miles around.  

Over 200 species of birds have been observed and documented in the area. Herons, egrets, gulls, osprey, vultures, and waterfowls all gather at the Conowingo Dam to feast, but the bald eagles are the true stars of the show. They engage in aerial acrobatics as they dive to capture fish in their enormous yellow talons, with their wingtips and tail feathers brushing the water. Airborne battles ensue as other eagles try to steal a successful eagle's catch. The flashing red lights and sirens indicating when the dam is about to release water often trigger a Pavlovian response in the birds. The eagles chirp and position themselves for a fresh deposit of fish.  

An estimated 250 eagles live within 25 miles of the dam and travel there regularly to eat. Some of the eagles who visit the dam are nesting pairs with established nests along the river. Eagle parents may be observed teaching their offspring to fish by dropping their catch and letting the juveniles retrieve the fish. When not snatching fish from the water, bald eagles can be seen perched on surrounding rocks, trees, and nearby power scaffolding. 

Bald eagles fish the Conowingo tailrace year-round, but their numbers increase during the winter months when eagles travel even longer distances to feed in the dam's never frozen waters. It's possible to see as many as 250 to 300 bald eagles at the dam on any given winter day. The best viewing is from Fisherman's Park on the dam's Harford County side in Darlington, Maryland.