How Far Can Bats Travel In Search Of Food Supplies?

           Some species of bat avoid the need to hibernate in winter by flying off to regions where food is more plentiful. Bat migrations were first suspected when observers noticed that many species of bats that were common in summer disappeared during winter, and were not to be found in any of the likely hibernation sites.


           The first research into these migrations was carried out in the same way as with birds - by marking individuals with rings on their forelimbs. Later, small ear-tags were used, but the principle remained the same: by recording the numbers on the tags whenever bats were recaptured, zoologists were able to build up a picture of each animal's movements.


           It becomes apparent that some species travels a long distance in search of better conditions. The noctule bat, a large bat equipped for fast, direct flight, regularly travels 900 - 1 100 km to its winter quarters. The migratory journeys of some of the smaller bats are even more remarkable. A common pipistrelle, for example, is recorded as having travelled 1 500km between Russia and Bulgaria.