Last week I happened upon this nesting Canada Goose (Anseriformes: Anatidae: Branta canadensis) keeping a watchful eye on a passing group of Ring-necked Ducks (Anseriformes: Anatidae: Aythya collaris). This particular goose chose to make her nest on top of a muskrat nest (Rodentia: Cricetidae: Ondatra zibethicus). In wetlands muskrats build these structures, known as “push-ups,” to protect themselves and their young from predators and the elements. Constructed from local vegetation, they feature underwater entrances and internal cavities above the water line to keep the muskrats warm, dry, and safe.
Canada Geese will often nest on top of muskrat push-ups because they provide elevated, open views of the surrounding area. Geese like to be able to see in all directions, always vigilant against intruders. I have to wonder what the muskrats think about the geese hanging out on their rooftops all day, however.