So this is why the bird seed hasn't been going down today.

Our one-legged Cooper's Hawk has staked out the place.

Notice he has only one leg. He was resident in our area a few years ago as a fledgling and had a broken leg at the time. We kept an eye on him and talked to the local raptor rescue group a few times. They said as long as he seems to be feeding himself, just let him be. We were happy to give him an area with plentiful sparrows, mice and snakes. I just watched him attempt (and fail, but feathers were lost) to take down a sparrow.

Clearly, he's made his way in the world. We're happy for him.