Biologists from the Patuxent Wildlife Research Center are studying the sea ducks that spend the winter in the Chesapeake Bay. The current project requires capturing ducks on the Bay with nets to check their health. Researchers want to know whether the decline in food availability in the Bay places a limit on the numbers of scoters and long-tailed ducks.
Sea ducks depend on mussels and clams for food. Unfortunately the crash of the oyster population appears to affect the supply of other shellfish as well, since they thrive in the same oyster beds.
He points to the canvasback and redhead ducks as a parallel. Before water pollution killed most of the bay's underwater grass beds in the 1950s and 1960s, as many as 1 million canvasbacks and redheads migrated to the bay. Now, with bay-grass acreage only a fraction of earlier levels, the number of canvasbacks found on the bay is about 50,000. Redhead numbers have dropped to a couple of thousand.
As for sea ducks, no one knows how many winter on the estuary. Perry estimates there might be 50,000 surf scoters, as many as 20,000 black scoters and probably 50,000 long-tailed ducks.
A biologist who flew a series of parallel flights up and down the length of the bay in 1994 in a search for sea ducks estimated from his findings that the number is more than 400,000.