I've reading the loon discussion that my question started with
interest. M. Price asked: What plumage do you think this bird was in?
How would you describe it?

It had a bright yellow bill, and it's plumage seemed bright, too. It
had those fetching loon speckles. I haven't mastered the art of plumage
i.d. yet. The Yellow-billed loon was with a more confusing loon... on
the second one, the bill seemed a lot darker, and the plumage seemed
muddier. They both swam far away when we got back with the scope, so it
was rather frustrating. They were doing a behavior I hadn't seen
before. They were putting just their heads in the water and scoping
along. They looked like they were skimming the surface to feed, with
their heads completely under water.
Kristi Streiffert
Coulee Dam