An imprint of an owl is seen on the window of a house in this handout photograph received in London on July 12, 2011. The homeowners returned from holiday early in July, 2011 to find the imprint on the window of their house in Kendal, north west England. Experts at the Royal Society for the Protection of Birds (RSPB) said that the marks on the window would have been left by 'powder down', a substance that helps many birds protect new, growing feathers. REUTERS/Sally and Duane Arnold/RSPB/Handout (BRITAIN