I once visited a castle ruin in lower Austria. Of course with my camera. There I found a little kitchen with a window and this bird coming over and over again to this window, not daring to fly in because of me. I was wondering, because the bird was carrying a grasshopper in it's mouth and suddenly I understood. After looking around I found a nest in the wall just behind where I was sitting, with at least two hungry baby birds in it... :)