From The Raptor:
On arrival at the property I approached slowly and immediately saw the window owl tucked up on an upstairs window ledge, head turned and watching my every step. The owl I noted as being a tawny owl, not a daytime flier unless disturbed. So, could this bird be breaking the tawny owl rule book or had it decided that this very open window ledge was its daytime roosting spot? This is very unusual as, being a predator, they are harried at every turn by the wee birds who would be in fear of loosing young or their own lives to a tawny owl.
Luckily I had permission to enter the building so I very quietly climbed the creaking stairs and peered into the bathroom in which the window was situated. The owl was unaware of me getting to within three feet of it on the other side of the glass, but my luck ran out in two ways. One, this double window was clean and clear on one side and all fogged up on the other. I wondered which window the owl was behind - yes, it was the fogged up window. Two, I snapped one picture, took another step and a floorboard gave the game away with a loud creeeeeeek. The owl was off in an instant, leaving the ledge empty apart from one feather stuck to the concrete.
Many thanks to The Raptor for pictures and story.