First published as: Beaugrand, Jacques P. (1976). An Attempt to Confirm Magnetic Sensitivity in the Pigeon, Columba livia. Journal of Comparative Physiology, 110, 343-355. ------------------------------------------------------------ An Attempt to Confirm Magnetic Sensitivity in the Pigeon, Columba livia Jacques P. Beaugrand Centre de Psychologie ExpØrimentale et ComparØe, UniversitØ de Louvain, Pellenberg, Belgium, and DØpartement de Psychologie, UniversitØ du QuØbec. MontrØal H3C 3P8, Canada Journal of Comparative Physiology - A by Springer-Verlag 1976 Received June 9, 1976 Summary. An attempt was made to test the sensitivity of homing pigeons to weak magnetic variations of the order of the ones naturally occurring on earth. Pigeons were first subjected to a cardiac orienting reflex test to 50 magnetic stimuli and to 50 control stimuli presented alone and randomly interdigitated. They were then subjected to a differential nociceptive conditioning procedure using the same magnetic and control stimuli for 100 trials under each stimulus condition. Cardiac activity was used as an index of reactivity throughout the study. The tests were performed in uniform magnetic fields using l to diameter Helmholtz coils. Results indicate that the magnetic stimuli presentations did not evoke a cardiac orienting reflex when compared to the cardiac orienting response of control pigeons to a neutral luminous stimulus. Moreover, results from the conditioning tests indicate that the magnetic stimuli were not used by the pigeons as a cue presaging the forthcoming shock. It is concluded that, in the present experimental situation, homing pigeons did not respond to small changes in the ambient magnetic field with changes in autonomic functioning. Results are discussed in the context of the inappropriateness of the stimuli and tests used to show magnetic sensitivity in birds. Introduction There is a growing literature suggesting that the earth’s magnetic field might be a source of directional information for some migrants and homing pigeons (Wiltschko and Wiltschko, 1972; Southern, 1972; Keeton, 1974x, 1974b; Walcott and Green, 1974). Evidence of this influence is mainly derived from research on the European Robin (Erithacus rubecula) and two species of European warblers (Sylvia communis and Sylvia borin) (Wiltschko, 1972, 1974; Wiltschko and Wiltschko, 1972, 1975x, 1975b) and on the Ring-Billed Gull (Larus delawarensis) (Southern, 1970, 1972). The results of research on the homing pigeon appear contradictory. Yeagley (1947) had reported one test release in which homing pigeons carrying magnets were disoriented when compared to a brass-carrying group. Subsequent attempts to repeat this experiment failed to confirm these preliminary results (Yeagley, 1951; Matthews, 1951; Bochenski et al., 1960). On the other hand. Keeton (1974a, 1974b) has shown that pigeons carrying bar magnets were disoriented at unfamiliar test sites when released under total overcast than under clear sky. Supportive evidence also comes from Walcott and Green (1974) who found that pigeons wearing a small Helmholtz coil around the head tended to fly in a direction opposite from home, when the artificial field produced had its axial inclination reversed (North up). Although magnetic sensitivity and its use by some invertebrates and lower vertebrates is known (Brown, 1962; Schneider, 1963; Barnothy, 1964; Ratner and Jennings, 1968; Martin and Lindauer, 1973) laboratory experiments using conditioning techniques have failed to show the existence of such a sensitivity in the pigeon (Orgel and Smith, 1954; Meyer and Lambe, 1966). One exception is the report of Reille (1968) on pigeons responding by heart rate accelerations to variations of an experimentally manipulated local magnetic field. However, responding level is low when compared to what is usually obtained in similar conditions using visual or auditory stimuli, leaving open the question of the biological significance of this form of sensitivity in the behavioural repertoire of the pigeon.