Night Watch Curtain

Night shadows swallowed the branch. Chilly air stirred outside. Freeze. Scan. Clear. A brittle curl of birch bark rested just outside my knot hole. I darted forward, grabbed the edge in my jaws, and hauled it inside. Heavy drag. Pushed it upright across the hollow entrance with my snout. It wedged neatly between two rough ridges of tree bark, blocking the dark draft. Safe shelter sealed. Only a sliver of moonlight trickles through the seam.