Photo: Torsten Prohl
Many soaring birds, including the Egyptian vulture, migrate mostly over land and avoid the open sea. The air immediately above the ground heats up and raises in warm air currents (thermals); the birds use them to gather height. Thermals do not form over open seas and there the vultures have to fly actively, thus losing a lot of energy. Exhausted by the long flight, many birds find their death in the waves. The young and inexperienced birds are the most frequent victims of the water. The migrants often rest on vessels, and even a small island can provide enough warm air for the formation of thermals which aid the vultures in their flight over the water barrier.