Published: Dec 12, 2019Find out more about our amazing bar headed geese...
Paignton Zoo is full of wonderful plants and exotic animals. It’s home to many beautiful, colourful and fascinating birds, although they often get overlooked in favour of the mammals. There’s a breed of bird that makes its home on the lake, quietly swimming amongst all the other birds, that has superhero powers…
Bar headed geese are amazing. They’re capable of achievements that humans can only dream about. They are the highest-flying birds - their migratory path takes them to 26,000 feet. They fly over the Himalayas and above Mount Everest, the tallest mountain in the world.
Over the years, Edmund Hilary and other Everest explorers told of seeing geese flying above them; their stories were put down to oxygen starvation hallucinations. The air over these tall mountains is so thin that helicopters struggle to fly and human hearts can barely beat, let alone exert themselves. How could geese be flying so high?
And yet they were. These resilient birds make the journey year after year. They travel from their breeding grounds in Central Asia to winter in South Asia as far south as India. How they are able to do it has been investigated recently with the help of a woman called Jessica Meira, a NASA astronaut no less.
She raised bar headed goslings who imprinted on her so that they’d follow her anywhere. She taught them to fly, first using a bicycle - when they couldn’t catch her by running, they took off and flew – then, as they got stronger and faster, graduating to a motorbike.
There were a few adventures during training when they got spooked. One landed in a hockey game and ran after players; another found a supermarket and started following people in and out of the automatic doors looking for its human parent.
When they reached adulthood they trusted her enough to fly in a wind tunnel at a research centre, even wearing masks and backpacks. This was a remarkable achievement, and a show of the trust these birds had in her. Geese can’t be bribed with food like other animals, but 7 of the 12 cooperated, and the data was invaluable, as previous studies had had to rely on geese on treadmills or at rest.
It had already been demonstrated that these geese have more capillaries around individual cells in their pectoral muscles than other related species that don’t fly at such high altitudes. These cells are dense with mitrocondria, which use oxygen to supply energy to the body.
By flying them in a wind tunnel, the conditions of their migration could be replicated. It was found that, when flying in such oxygen-limited conditions, the geese slowed their metabolism and the temperature of their blood reduced. In mammals, exertion makes blood warmer, but when blood is cold it can carry more oxygen. As the temperature in the veins near their lungs drops, they can circulate more oxygen to the chest muscles to enable them to endure the arduous flight.
Human organs can be damaged in low oxygen conditions, but the geese can fly for hours. The birds evolved over millions of years to fly over the mountains; as the mountains were pushed up by geological forces, they made the birds fly higher still.
If we can understand how bar headed geese are able to deal with these conditions, we might be able to help people suffering from problems related to oxygen starvation, for example as a result of strokes or during childbirth.
So, next time you spot a pretty and unassuming grey and white goose with distinctive black bars on its head coming up to the feeding station on the decking beside the lake, think about just what that species can achieve.