One of the sure signs of spring is nest building. I have been watching a lady mink work at building a nest since I got up this morning. Every five minutes (on average) she goes out to the edge of the ice and dives. Shortly thereafter, she pops back up with weeds in her mouth. She swims into the crib dock and ripples can be seen under the boathouse as she must be moving around. When the ripples stop, she heads back to the edge of the ice. I would think she would be tired by now but the urge to build a nest must be stronger than fatigue.
And some people think there is nothing to do at the lake during the winter. All you have to do is open your eyes and you'll see plenty of interesting things.