I have three garbage cans by my back door. About a year ago a possum caught himself in one of them.
Yesterday evening, when I came home from an errand, I noticed that the middle can was tilted at an angle--not an easy thing to do--so I straightened it up and moved the first one against it to prevent anymore unexplained movement.
When I did that, I noticed a small gray bird (probably a house sparrow) in the bottom of the empty middle can, and he was breathing. I didn't know if he was dying or resting (strange place for either one). I just left him there, because there didn't seem to be anything else to do. Later, when I was locking the doors for the night, I checked the bird again. Still breathing.
This morning I went to get my clothes out of the dryer, by the back door, and when I glanced out the window in the door, there was a gray and white cat sitting on the welcome mat as though he belonged there. He made no move to leave, so I opened the back door, and he ran away.
Then I peeked into the middle can, but it was empty. And my other garbage can, the one with trash in it, was tipped over.
The evidence isn't irrefutable, but I blame the cat, who has never darkened my doorstep before. Bad bird-killing, garbage-can-knocking cat!
Update (Friday afternoon):
When I got home from having a reunion lunch with a bunch of people I worked with when I first started at my last job, I didn't see the cat. But I heard a fluttering sound in the back garbage can, where I have some cardboard boxes. I couldn't see anything, but the fluttering would come and go, so I pulled out the top box and put it in the empty trash can. That's when I noticed some bird doodee on a couple of the boxes.
The bird was under an upended box, and when I lifted the box, the bird started flying, but his wings kept hitting the side of the garbage can, and he couldn't get out. So I took out the rest of the boxes and gently tipped over the garbage can.
The bird flew out of the box in such obvious panic that he ran into the wall of the house next door and dropped into their grass. He flew away a couple minutes later, and I expect he's now safe from the evil cat.
All's well that ends well...