They can get terribly annoyed if you're not quick enough feeding them, can't they? Mine have a routine of flying back and forward past the window to attract my attention. They're feeding chicks at the minute.
Mine clucks as well! Seems to be very fond of fruit such as apples that have gone soft. Their favourite Snacks are grapes. The robins are doing courtship feedin, passing sunflower seeds to one another. Had a juvenile dunnock today. The great spotted woodpecker dropped in and was foraging in the moss on the dry stone wall.