Correlation between magnetic storms due to solar spots and pigeon homing performances

The biological action of magnetic field variations has been clearly pointed out in the last years particularly on migratory birds. They have seen that it is possible to change the direction of preflight excitement in the experiments with registration cages, as well as of the mean vanishing point in homing pigeons during the flight with appropriate magnetic artificial stimuli. More recently deviations of migratory behaviour correlated to magnetic storms of solar origin have been also reported. Our observations con cern the decrease of the "homing efficiency" in pigeons during races, with the increasing of solar spots. This is shown by a negative correlation between the Wolf nos. of solar spots and the two tests used: the % of arrivals within the first nightfall and the speed of the first arrival in each race.