Waterfowl are just beginning to migrate through Pennsylvania so now's a good time to learn the name of an important fieldmark on ducks.
It's a useful fieldmark when trying to identify mallards and American black ducks. The speculum on mallards is blue with white borders. On black ducks it's purple without white borders. Unfortunately mallards and black ducks can hybridize and the result can be confusing!
(photo by Chuck Tague)