Me thinks someone is trying to pull a fast one.
Unless I'm mistaken, that looks like cypress knees and rot under a missing board in the dock.
You dont know a beaver nest when you see one do you lol.
Nope! Too bad you didn't get a picture of the eggs in it.
Luckily I don't have beavers at my place. The only thing that I've seen is muskrats, and they are treated with extreme prejudice.
The beavers had to be pretty desperate to chew cedar (I think). Around here they won't touch the stuff.