Migratory habits of 3I species of vagrants from North America and 73 candidate species not recorded In elther Bntain or Ireland during the 30 years 1947-76 were analysed by multiple regresslon. There was a sIgnificant correlation between the number of British and Irish records and the west-to-east component of normal migration, standard deviation of body weight, mlgratory dIstance, and abundance on the west coast of the North Atlantic. The candidate specles were ranked in order of likelihood of successful transatlantic flight based on the four Input variables (table 2).