The verified record no other bird matches
The bar-headed goose holds the verified altitude record for a bird crossing a mountain range under its own power. Radar tracking published in Science in 2011 by researchers at Bangor University recorded individual geese flying at 6,400 metres above sea level during their Himalayan crossing, some potentially higher, though 7,290 metres remains the most-cited upper estimate from historical field reports. At that height, the air contains roughly 50 percent of the oxygen available at sea level. A human without supplemental oxygen at that altitude loses consciousness within minutes.
