While cleaning out nest boxes yesterday at the Fletcher Wildlife Garden, I came across several mouse nests (they usually make winter nests in the boxes in autumn). This box had four little guys in it, and at one point three of them were lined up along the back ventilation opening, peering out. Unfortunately, I wasn't quick enough to get a photo, but wish I had! This is likely a white-footed mouse, but the deer mouse, also found here, is very, very similar.