Small, brown, diving. That can only mean one thing – a dabchick. Sure enough, when a bird bobs up a few feet away, my hunch is confirmed by the dark crown and back, and paler buff cheeks, of a little grebe (Tachybaptus ruficollis) in winter plumage. Its generic name means “fast-sinker” as the UK’s smallest grebe is a dab hand at diving. Unlike me, it can plunge into the lake without any fear of cold-water shock due to its dense, waterproof plumage.