It could be getting mud to help build whatever it's building. Is there a dam or a beaver house on the pond?
I'd be very tempted to be laying on the bank where the camera is positioned with a .223.
No beaver dam or other beaver structure that I have seen. I would not even know they were present except for the cameras on the wood ducks.
I am in the city limits, so I'm nervous about a rifle. I guess I could get out my 410, but the only hiding area is on the dock where the cameras are between 100 and 150 feet away.