Pigeon Homing in the Meteorological and Solar‐geomagnetic Environment: what Pigeon Race Data say

AbstractIn this statistical analysis, the fastest 25% of homing speeds in 5955 races conducted in West Germany on 194 days in 1973–1990 and the return rates in 18 pigeon races held in 1932–1957 in Italy were examined with respect to distance, cloud cover, wind, sferics, solar and magnetic variables. 1. Under sun, the speeds rapidly increased with distance from 120 up to 240 km and slowly declined beyond 240 km. 2. Correlations between race and wind speeds were maximized by rotating clockwise and extrapolating the local surface wind linearly according to the average wind profile (difference between the mean surface and mean 900 m‐height wind vector). The best predictors indicated the speeds of the winds the birds encountered aloft, which were blowing at lower heights in headwinds than in tailwinds. 3. The air speeds correlated negatively with the effective wind forces roughly in agreement with Pennycuick's theory of bird flight. 4. Rates of atmospherics (2.8–38 kHz, 0.02–0.4V/m recorded in Berlin) correlated negatively with the speeds. 5. Under sun, the difference between the fastest and slowest speed correlated with sunspot numbers (R) in a very active solar cycle (1979–1987), but not in the preceding and following cycles which had lesser activity. 6. Under sun, the speeds correlated directly or indirectly with solar and magnetic activity (25% and 21 % of the samples per year and per homeward direction, respectively), but did so only in 9.9% and 6.9% of samples (respectively) when races to the same home area were sampled over the years. Under overcast, most of the correlations were negative. 7. While magnetic disturbances appeared to coincide with higher speeds inconsistently under sun, they appeared to interfere with the speeds consistently under overcast. Under sun, the seasonal median speeds, unlike the daily median ones, correlated negatively with magnetic activity. 8. Hourly variations of the geomagnetic field components correlated negatively with the speeds in 1973–1975 in western, but positively in eastern and southern, homeward directions. 9. The return rates in Italian pigeon races were best predicted by hourly variations of the horizontal intensity of the regional geomagnetic field and second‐best by sunspot numbers. 10. The significance of the results for understanding the role of the meteorological and solar‐magnetic environment in pigeon homing is discussed.