Wirkung des Mondlichtes auf die Nachtaktivität von Zugvögeln. — Lotsenversuch an Rotkehlchen (Erithacus rubecula) und Gartenrotschwänzen (Phoenicurus phoenicurus)

Summary

8 Robins (Erithacus rubecula) and 3 Redstarts (Phoenicurus phoenicurus) were maintained in registration cages in autumn 1965. Locomotor activity was registered continuously under natural light conditions, temperature remaining fairly constant. All but one bird developed nocturnal restlessness (‘Zugunruhe’) at least during the migratory season (Figure 1). 8 out of 10 birds showed a higher mean activity at night during full moon phases than during new moon phases; 2 birds showed roughly equal activity during both phases of the cycle (Figure 2). Since the measurements of nocturnal activity at least partially correspond to migratory motivation, it is reasonable to assume that free-living individuals of the species investigated are more active during nights in the full moon phase and possibly fly farther than at dark nights.