Flocks of the 2,000-plus avid bird watchers who have spent December heading for north Norfolk are expected back again from Sunday - if an extremely rare visitor decides to spend the new year in the county.

Each will be armed with their brand-new 'British list', to record species seen throughout 2012.

And they will be hoping to start the new year by ticking off a little North American wader called the western sandpiper which has made Cley Marshes nature reserve its home since November 28.

A western sandpiper has never before been seen in Norfolk and there have only been about eight previous records of its appearance anywhere in the British Isles, according to a spokesman for the Norfolk Wildlife Trust-run reserve.

'It should be wintering in the Caribbean but it probably got blown off course and got caught up in a jet stream,' he explained.

Identifying the juvenile bird, which measures 15cm (16in) from bill tip to tail, initially caused problems and it took 48 hours of swapping information with experts across the Atlantic before it was confirmed as a western, rather than a not-as-rare semi-palmated, sandpiper.

Confirmation sent the bird world into a flutter and visitors have travelled from as far as France, Germany, Belgium, Holland, and Ireland to see it.

Their arrival has boosted sales of day permits to non-trust members, and takings in the reserve's visitor centre shop and cafe, according to the spokesman.

'Occasionally it flies off but most of the time the bird is roosting and feeding and can be seen from the hides.'

It was unlikely to return to North America and, if it survived the winter, it would probably get the urge to migrate north sometime in March.

The spokesman added: 'It is exciting to see it and it underlines Cley's importance as a reserve for residents and migrants.'