I learned on Rarebird.org that there were Horned Grebes in the area.
Sure enough, I started seeing them on the river, too; nothing looks quite like a Grebe, except a Grebe. The trouble is, they don't stay in one place long. They float down river and when they aren't floating they're diving.
After many failed attempts, I was finally able to get enough of a shot to correctly identify them this evening.
If you'd like to see a better photo, click here.
I've never seen a Horned Grebe here before.
They spend their winters on the Atlantic Ocean and breed in Canada.