When I was a kid we had a great big snowey owl flopping around behind our house, it puked up a mouse and sat very still for hours at a time, we called the game department because we were worried about our dogs, it would not fly away and we had bird dogs that were wanting to retrieve it. they came out and took the bird and the mouse. the bird was treated and nursed back to health at a bird refuge in canada. the mouse was full of Decon (pestiside). How close to any houses were you (as a crow flys, in this case how a owl flys) maybe it was sick from poisen...DJ