5 March 2014

The frozen Great Lakes have prompted a lot of gulls and waterfowl to visit Pittsburgh’s rivers this winter.  Bird reports for the past month often mention long-tailed ducks, white-winged scoters, red-breasted mergansers, redheads and canvasbacks.

These photos by Steve Gosser reminded me that of all the birds listed above, redheads and canvasbacks are the most confusing.  Both are diving ducks with red heads, black breasts, dark butts, and white or gray backs.   Both could be named “redheads,” so what is the “canvas” back that makes the difference?

Despite their names the “canvas back” is not the easiest way to tell them apart.  The best way is to look at their heads and bills in profile:

• Canvasbacks have long sloping foreheads and bills that make a straight line from forehead to tip.
• Redheads have round, bulbous heads and an angle where the bill meets the face.

If both birds are present, the canvasback is the larger one.  If the light is good you’ll see additional distinguishing features.  Let’s take a closer look.

Redheads have pale bills with a black tip.  The males’ backs are gray and eyes are yellow.  Up close you can really see the bulbous head.

Canvasbacks have black bills. The males have red eyes and white backs with a faint pattern like woven canvas, but that’s something you’ll never see unless you’re a duck hunter.  The sloping face and forehead are really evident up close and are the main way to identify female canvasbacks who are basically brown.

It’s easy for me to tell the two ducks apart but my brain gets in the way sometimes when I have to name them.  I may look at a canvasback and think, “That duck has a red head so it’s a … redhead.”    Nope!

The hardest part is mentally finding the right noun.

(photos by Steve Gosser)