This was posted by Jerry Ulett on the groaners listserv.
One warm afternoon an owl was flying around and needed to rest so he purchased on a window sill. As luck would have it, it was the open window of a hospital where an operation was in progress and the owl got a whiff of the anesthetic, causing him to fall into the building and onto the floor.
The surgery had just ended and the doctor, hearing the sound of the owl hitting the floor, picked up the bird, checked it’s throat and removed what he deemed to be bad tonsils. He then examined the other end of the owl, excised its hemorrhoids and returned the owl to the window sill.
Two days later, the owl was talking to another owl who had asked him what he had been doing lately. He answered, “I’m not sure what happened, but day before yesterday I stopped for a rest on a window sill and ever since I haven’t been able to hoot worth a shit, nor shit worth a hoot!”