Related Topics:
bird
migration
flight

The majority of birds fly at altitudes of about 150 meters (around 500 feet) or lower. During migration, however, many species fly at higher altitudes, often around 610 to 1,525 meters (2,000 to 5,000 feet). Exceptions include Rüppell’s griffon vulture, which has been recorded flying at an altitude of 11,300 meters (37,000 feet)—higher than the cruising altitude of many commercial airplanes. Birds fly at high altitudes as a result of migratory patterns that involve navigation over mountain ranges or other geographical barriers.

Birds can fly at high altitudes owing to certain physiological adaptations. For instance, they have a highly efficient respiratory system that allows them to extract more oxygen from air than mammals, which is critical at high altitudes. Birds also are lightweight, having pneumatic bones that enable them to soar effortlessly. In addition, some species have unique adaptations. The bar-headed goose, for example, which has been observed flying over the Himalayas, can reduce its metabolic rate to match limited oxygen availability and avoids flying in strong winds to further optimize energy consumption at high altitudes.

Birds also often take advantage of air currents to reach higher altitudes. Soaring birds, such as eagles and vultures, use thermal updrafts to gain elevation without expending much energy. These birds have broad wings with slotted tips that help them catch and ride these currents.

The Editors of Encyclopaedia Britannica