Smithsonian.com

Bar-headed goose with a Mount Everest-simulating air mask. Photo: BBC

Next time you’re cruising on a short flight in Mongolia or Tajikistan, take a peep out the window and see if you can spot any bar-headed geese sharing the air space. The birds soar up to 20,000 feet on their migration routes between Central and South Asia where they have to scale pesky obstacles like the Himalayas. In order to figure out how the extreme geese achieve those heights, researchers from the University of British Columbia strapped them into wind tunnel test flights simulating the stark atmospheric conditions experienced at the peak of Mount Everest.

The BBC reports:

During “test flights”, birds wear masks they are trained to wear as goslings, which provide them with oxygen levels that simulate high altitude.

The masks also collect gas that the birds breathe out, measuring how much precious oxygen they use in flight.

In order to find out just how high the birds could fly, Dr Meir and her colleagues recreated the oxygen and nitrogen levels that the birds would receive at 6,000m and at 9,000m above sea level. This is approximately 10% oxygen and 7% oxygen respectively.

While the wind tunnel results are being analyzed, the researchers provided this cool slow motion video to tide over the goose-curious.

More from Smithsonian.com:

The Goose that Flies Over the Himalayas  

Inside the ER at Mount Everest