Who are you?..

First I heard whistles in my hotel room in Westhill Aberdeen I thought kids were playing nearby or somebody has just learned how to whistle and was enjoying his/her new skill just by my window. I poked through the window and saw this bird looking very curiousely at me. Our eyes met and we were staring at each other for a while. I had no problem with the pic, but the name of the bird remains unknown to me. If you know who this bird might be, I'd appreciate your tip.