It’s relatively easy to identify ducks on water because they look like the pictures in the field guides.

Even when the female is boring, the male is usually colorful as shown in this pair of American wigeons (Mareca americana).  He’s the one with a green nape, white crown, white butt, and black tail.  The black and white features are unique, even from a distance.

But in flight it’s another story.  Here are three American wigeons in the air.  I’m stumped!

Why are they so hard to identify? Because we see two body parts that aren’t visible when they’re swimming — bellies and underwings.  Who knew that wigeons have white bellies?

The best way to identify ducks in flight is by using black-and-white drawings.  This Washington Department of Fish and Wildlife brochure is the closest thing I’ve found online:  Ducks at a Distance.  See pages 50-51.

(photos from Wikimedia Commons; click on the images to see the originals)