Many studies have dealt with the spectacular bird losses during migration that occur in the eastern United States at airport ceilometers (Spofford 1949, Howell et al. 1954, Johnston 1955, Johnston and Haines 1957), TV towers (Tordoff and Mengel 1956, Brewer and Ellis 1958, Kemper 1958, 1964, Kemper et al. 1966, Stoddard and Norris 1967, Graber 1968, Taylor and Anderson 1973) and tall buildings (Overing 1936, 1937, 1938a, 1938b, Pough 1948). From these have come an increased knowledge of the biology of migratory species and, in certain cases, suggestions leading to a decrease in the number of birds killed (Tordoff and Mengel 1956, Cahalane 1966).