Flying High: The Unique Physiology of Birds that Fly at High Altitudes

Birds that fly at high altitudes must support vigorous exercise in oxygen-thin environments. Here we discuss the characteristics that help high-fliers sustain the high rates of metabolism needed for flight at elevation. Many traits in the O2 transport pathway distinguish birds in general from other vertebrates. These include enhanced gas-exchange effectiveness in the lungs, maintenance of O2 delivery and oxygenation in the brain during hypoxia, …