Twitchers were delighted by the arrival of a Pallas's rosefinch on North Ronaldsay, Orkney, in June 1988; a Mugimaki flycatcher near Patrington, Humberside, in November 1991; and a brown flycatcher on Fair Isle, Shetland, in July 1992. Many travelled hundreds of miles to add the birds to their 'life lists'.
But the British Ornithologists' Union Records Committee (BOURC), the establishment body of eminent ornithologists, has decided against adding them to the official list of wild birds seen in the British Isles.
Some twitchers are so angry that they are talking of setting up a breakaway body to decide which birds are genuine new arrivals and which are not.
'It would be an understatement to say twitchers are incensed,' Ian Mills, one of Britain's leading twitchers, said this weekend. 'Many regard the decisions with contempt.'
They consider the sightings to be genuine first arrivals of birds which have drifted thousands of miles off course during migration. However, the committee thinks they may have escaped from captivity in Britain or on the near Continent.
Mr Mills, a Tyneside headmaster, said that some twitchers 'feel just as qualified to consider all the arguments for and against and come up with decisions which are more in touch with common sense'.
Recently there have been large-scale imports of exotic birds from China and the former Soviet Union despite the protests of conservationists who fear for the future of native populations. In the June edition of British Birds magazine, David Parkin and Ken Shaw of the BOURC say this has led to 'many more species that are potential vagrants to Britain turning up in cargoes here - and subsequently escaping'.