Common Cranes (Grus grus) usually gather in late October or early November to travel to warmer areas. They leave northern Europe for a long journey of 1,553 miles (2,500 km) to the south and the Mediterranean, along a corridor almost 124 miles (200 km) wide. Some populations even go as far south as Sudan and Ethiopia. They regularly stop to rest. They sometimes fly at night to benefit from cooler, denser air that better regulates their body temperature during exercise.