How do bats cover distances?

Birds navigate using the Earth’s magnetic field. This can often be confusing because of the variation in the Earth’s iron crust deposits. In such cases birds rely on the sun. A study found that bats might be nocturnal but the sun is also their migratory compass. Researchers took a group of bats north of their home caves during sunset. They altered the magnetic field of the area from north to east for half the bats. The bats did not know which way was south and could not find their way back. The rest of the bats flew back home. After the sun set completely, the researchers again altered the magnetic field for another group of bats from north to east. In this case all the bats knew which way to fly south. The bats did not depend on the magnetic field this time. They aligned their journey with the direction of sunset.

Source: Down To Earth, May 2010