I saw these first Common Mergangers in the Susquehanna River, downstream of the Conowingo Dam, in Susquehanna State Park, MD, on December 17th, 2005. They flew away shortly after I got this photo, so I couldn't get into position to get a clearer shot.

I saw several Common Mergansers from Perryville Park in Cecil County, MD on March 1st, 2008.

This female bird was on the lake at the Susquehanna State Park picnic area. It was swimming around with a male Mallard.

These Common Mergansers were near Chestertown, MD on January 16th, 2012.

I saw this one at Swan Harbor Farms on February 22nd, 2013.

This bird flew over the Susquehanna River near Port Deposit, MD on March 20th, 2013.

I saw several young birds at Swan Harbor Farms on June 21st, 2014.

I saw these birds at Bombay Hook NWR, DE on January 18th, 2021.