Troublesome Scaup

Photos and text by David Roemer profess to illustrate how to differentiate between Greater (Aythya marila) and Lesser (A. affinis) scaup. Maybe so, but I'm still confused.

In light of my recent efforts to identify scaup in the field in southwestern Michigan, I've about reached the conclusion that separating these two species with any degree of confidence is nigh impossible under any but the most favorable viewing conditions.

My thanks go out to Roger Everhart, the self-proclaimed Minnesota Birdnerd, for bringing Roemer's contribution to my attention (here).