This is a white-white-footed mouse, trying to return to the bluebird nesting box from which it was just evicted. I cleaned boxes Sunday, pulling old nests, and propping open the doors so mice won’t spend the winter there, as this one intended. I found six mice, two in one nest, four in the other. The boxes were stuffed with grass and acorns. Mice are bad housekeepers, urinating in the nest until they leave in the spring. It fouls the box, a mild description; the wood becomes soaked. Last year I had to fill a box with sand, trying to absorb the wetness. It works if you wait long enough. On my rounds Sunday, I found half a dozen bluebirds on the golf course where the boxes are kept. The species often migrates late, waiting until weather drives them south. They don’t leave the country, just moving south until they find milder conditions. Right now, here, they’re living on berries. If you have nest boxes yet to be cleaned, best do it before it snows. Clean the house, prop the door open, go back in April to close it up for next spring's nesters.
An update on the Green Heron we've seen almost daily for over two weeks: it returned Sunday, briefly. I learned that it is not the late migrant we believed. Average departure time for birds in southern Minnesota is Oct. 23. There are records of Green Heron sightings in the metro area for late November and December.