From RSPB site:Fieldfares are large, colourful thrushes, much like a mistle thrush in general size, shape and behaviour. They stand very upright and move forward with purposeful hops. They are very social birds, spending the winter in flocks of anything from a dozen or two to several hundred strong. These straggling, chuckling flocks that roam the UK’s countryside are a delightful and attractive part of the winter scene.
via Flickr http://flic.kr/p/hZFXDS