Since a Gold-winged Warbler flew across the Atlantic and attracted 3000 people in one day to a supermarket car park, identifying rarities has become the birdwatching activity of the 1990s. "Twitching", as it is called, now has over 15,000 dedicated people, with magazines, telephone hot-lines and Internet sites spreading information on what has been seen, when and by whom. This text catalogues the events and problems involved in identifying the first and subsequent sightings of the rare birds that have appeared in Britain and Ireland. It brings together information on the weather conditions, the problems involved in seeing each particular bird, who saw it and how many times that species has reappeared and where. This is the information that is of interest to twitchers, as it gives them a unique insight into when the species might reappear, and thus when they should organize their trips.