A case of highly pathogenic avian influenza (H5N1) has been confirmed on a free range turkey farm in Norfolk, marking the start of the bird flu season in Britain. All birds on the farm will be culled, and a 3km protection zone and 10km surveillance zone have been established. The UK government has increased the avian influenza risk level in wild birds from 'medium' to 'high', and in poultry with suboptimal biosecurity from 'low' to 'medium'. Bird keepers are advised to report any signs of disease immediately, and in England and Wales, all bird keepers, including those with a single bird, are required to register with the government to prevent future outbreaks.