Which bird flies the highest?

The highest-flying bird on record is the Ruppell griffon vulture, an African vulture. In 1973 one was tragically struck by an aircraft over West Africa at an altitude of around 11,300 metres, higher than Mount Everest and near the cruising height of commercial jets. These vultures can survive at such extreme altitudes thanks to a special form of haemoglobin that absorbs oxygen very efficiently in the thin air. Other high fliers include the bar-headed goose, which crosses the Himalayas at altitudes above 7,000 metres during migration, and the common crane. Birds fly high to cover long distances efficiently, catch strong winds, or migrate over mountain ranges. The air at these heights is bitterly cold and holds little oxygen, so only specially adapted species can endure it.