Apparently the commonest finch and the second commonest bird in the UK, nonetheless the humble Chaffinch deserves some page time here. Wikipedia is a mine of information, and from it I learn that it's so called a "Chaff finch" because of its habit of picking through the grain left out in farmyards amongst the chaff. As with all finches it has a robust beak for picking out and cracking seeds and you can see it has one in its beak here.