Many diving ducks are attracted to Lake Ontario because of the abundance of zebra mussels, a much sought after food source for water fowl and an invasive pest for marine biologists allergic to shellfish. Scoters are well-equipped to handle cemented clusters of zebra mussel because of their large mouth and strong serrated bills. I've seen Scaup swallow clusters of mussels too. I'm not sure how warmer lake waters through climate change will affect the mussel population and the number of winter water fowl the lake will host in subsequent years.