I heard a knock at the window frame. Thump thump. I got up from the kitchen table and looked out the window. No one was there. Just a chickadee picking seeds from the bird-feeder. Then I heard it again. Thump thump. I noticed some movement out of the corner of my eye. A downy woodpecker gripped the edge of a brick with its feet and tapped at the wooden window frame with its beak. Apparently, it was hunting for insects.