The BBC reports that Kingfishers seem to have survived last year's harsh winter and in fact are booming, if popular reports are to be believed. An annual British Waterways survey showed a 217% rise in reports by members of the public, which is a surprise result given Kingfishers' susceptibility to very cold weather. Of course it's possible that people are more tuned into them recently after high-profile TV and general media coverage, such as Halcyon River Diaries, and are reporting them more readily whilst the actual wild numbers aren't much changed, but I would hope that their survey tries to accommodate such phenomena.

Read all the way to the end of the BBC article for an interesting aside on how the RSPB was originally formed, and what it has to do with Kingfishers specifically.