Pigeon Powder

A wood pigeon, I think, has flown into the window. I didn't find a body so I'm hoping that it survived the trauma. The mark on the window is the bird's powder down. Pigeons don't have a preen gland and clean themselves by spreading the waxy dust from crumbling special down feathers. I can just about make out the shape of the bird from the window splodge. I blipped a much better example in 2014.