SEVERAL investigators (Riviere, 1929; Kramer and St. Paul, 1950; Matthews, 1951; Hitchcock, 1952; Riper and Kalmbach, 1952; Pratt and Thouless, 1955; Michener and Walcott, 1966, 1967) have all reported that when pigeons trained to fly in a single direction were released from points off the training line, the birds continued to fly in the training direction. Wallraff (1959) and Graue (1965) both...