There are birds that eat wasps; robberflies will kill wasps. I watched one of my hens snatch wasps out of the air and eat them, although just one, she might be a little crazy.
Little story - dh has a shop that he hasn't yet turned into his workshop. Every winter, the mice move in and so do the wasps. Interestingly, when dh makes a periodic inspection, he will find thousands of wasp wings lying on the floor. We think the mice must eat the wasps and leave the wings.
Can't think of another explanation.
Edit to remove picture - wrong picture and wrong thread.
