Pretty much any sapling within 5 yards of the water on our property has been beavered. After punching holes in one of their dams, I have to say that they're impressively clever. They anchor Y branches with the lower leg into the mud on the downstream side, using the V to hold the lateral members of the dam. They also seem to interlock the branches and select them by appropriate size and use natural features to assist the structure. It all adds up to a good amount of work to punch a hole useful enough to equalize the ponds before they patch them up overnight. We've even had cheaters installed and they just build a dam farther downstream. As frustrating as they are, while a lot of people would hate them for the trouble, I respect their capability and they're just living their lives. Plus, the ponds that surround our property like a moat are down to their engineering in the first place.