Everyone can recognize ducks: They are the birds that swim. In fall and winter, we have lots of ducks, along with geese and swans, their similarly easy-to-recognize relatives. But here’s the trick: ...

In my last column, I posed a question that went something like this, “when is a duck not a duck.” The answer is when it is a merganser. Then I wrote about the common merganser, which is a member of ...