There are many waterfowl identification pairings that can be confusing to sort out. One such example is male ring-necked ducks and male lesser scaup. Both of these divers have dark heads, chests, and rear ends combined with light sides. One difference between these two, which you can see from quite a distance, is their back color. Ring-necked males have a dark back and by “contrast”, male lesser scaup have a gray back. Not a huge difference, I know. I have a silly hook which helps me remember the difference. I think of the word scrape when I see a scaup. Like the color on the scaup has been scraped off, leaving gray. It’s goofy, granted, but it helps me remember the difference. If it helps you next time; great.