The face at the window

Was just on my way into Tesco on Duke St when I noticed this feller sitting on a window ledge at the top of the building opposite (3 floors above the Lioness of Leith). Definitely seemed to be waiting for something - or someone. I know people do feed the gulls occasionally, but on one's own windowsill? I wouldn't fancy that vicious beak and cold hard stare that close.....