A duck's nest on an artificial island

Since when do ducks build artificial islands for their nests? Well, they don't.

What you are looking at is the winter lodge of muskrats (Ondatra zibethicus). They aren't really rats at all, they are more like small beavers, and, like beavers, they can build such lodges.

Apparently, a duck decided it would make a good place for a nest. I'm not sure the muskrats agree, but I have not seen a fight yet.

^{Olympus Stylus 1s, 240mm, ISO200, f8, 1/400s}