Which goose species migrates over the Himalayan mountains?

The bar-headed goose migrates over the Himalayan mountains.

This Central Asian goose breeds around high-altitude lakes on the Tibetan Plateau and in parts of Mongolia, Kazakhstan and Russia. It migrates south to winter in South Asia, crossing the Himalayas between its breeding and wintering grounds.

Its high-altitude journey has attracted scientists because the air contains less oxygen and flight becomes more demanding. Bar-headed geese have unusually oxygen-efficient lungs, blood and muscles, including hemoglobin with a high affinity for oxygen. They also tend to cross at night or during cooler periods, when dense air can make flight somewhat easier.

Older accounts sometimes claimed that these geese routinely flew directly over Mount Everest. Tracking studies indicate a more nuanced picture: many birds use valleys and passes, and most recorded flight occurs below the highest Himalayan peaks. Even so, the species remains one of the world’s highest-flying birds.