The method of bat-banding contributes significantly to the study of the migratory behavior of bats. It was discovered by banding that Big Mouse-eared Bat (Myotis myotis) fly over 100 km to their winter quarters. Other species such as the rough skin bat (Pipistrellus nathusii), the Small Noctule (Nyctalus leisleri) and the noctule (Nyctalus noctula) fly even over 1000 to 2000 kilometers between summer and winter habitats. The small mammals are crossing state borders of course. In summer in the northeast German lowlands ringed rough skin bats were reported from the Netherlands, Central and West Germany, Switzerland, Italy and southern France.
The cross-border flight activity of bats also makes the cross-border protection of animals very important. For this reason, the "Agreement on the Conservation of European bat populations" in 1991 (UNEP / EUROBATS) was signed by now comprising 26 European countries. In Germany all bat species are protected by the Federal Nature Conservation Act.
In the 70 years long history of bat-banding approximately 350,000 bats were individually marked in Germany and neighboring countries (eg Netherlands, Poland and Austria). The rediscoveries by the persons who ringed the bats themselves because of the quarter fidelity of bats is very high and can exceed 25%. In contrast, only about 1% of the rediscoveries are real remote findings in greater distance from the location of banding.