I discovered Smooth Alder, Alnus serrulata, along the shore, one after another until I realized that this bush was all over the place! I'd been walking right by it without noticing the catkins or cones. It's a beauty, isn't it?
I'm not absolutely sure on the ID. It's definitely an alder, but it could be Speckled and maybe even Mountain although the bud shape leans toward either smooth or speckled. Once it leafs out, I'll have a better idea.