Flight physiology and adaptations/limitations for high altitude flight

Lucy Hawkes

University of Exeter, UK

Among vertebrates, birds undertake the longest, fastest and highest migrations of any taxonomic group, largely owing to their unique cardiorespiratory system, which permits for very large rates of gas exchange. This has helped them to function particularly well at altitude – where other taxa reduce energy expenditure, birds have not needed to, and can maintain dynamic flight across even the highest altitudes in the world, in the Himalayas. The physiological mechanisms that make this possible are common to all birds, but some species have enhanced capacity to acquire oxygen, even at extreme altitude. Importantly, this physiological capacity interacts with some major challenges and opportunities for the future of biodiversity. First, this enhanced physiological capacity alters the range over which birds can spread disease, and may interact with their ability to respond to climate change-driven range shifts in their predators and prey. Second, during migration, avian physiology is very dynamic, and birds have “solved” the major medical challenges of hyperglycaemia, obesity and sarcopenia that now probably account for the majority of global healthcare spending. Finally, pushing into medical spaces, a new frontier of ‘physiologging’ is emerging, making use of biologging technologies that have been developed for medical use, but that provide novel parameters for better understanding the biomechanics, energetics and ecology of a range of species.