The Bar-Headed Goose Flying over the Himalayas

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The bar-headed goose， one of the most common waterfowls on the Qinghai-Tibet Plateau， is named after the two black stripes on its head. A bar-headed goose looks quite stupid. Their images can be found everywhere， no matter whether they come from the Changtang Plateau in northern Tibet， the valley from midstream of the Yarlung Zangbo River in winter， the crop fi elds of the suburbs of Lhasa， or in the Dzongyab Lukhang Park downtown.

Though a waterfowl， a bar-headed goose lives mainly on land but often haunts around the waterside and shoals. It walks clumsily like a duck. The bar-headed goose living on land does not mean that it is not a swimmer. It actually swims well and fl ies second to none， a genuine model of the birds which develop well in the all-around fi eld of land， air， and water.

The bar-headed geese like living together. No matter if it is in winter， the breeding season， or during the days of migration， they move in fl ocks. The flock gathers gradually from a dozen birds to hundreds and then thousands. The biggest flock of barheaded geese can be seen in the crop fields near the Lhasa River in winter when they look for seeds left after the harvest. Bar-headed geese feed mainly on plant seeds.

The bar-headed goose is migratory. Every September and October， the creature flies south to spend the winter in areas of low altitude like India， Pakistan， Nepal， the midstream of the Yarlung Zambo River， and the grassland and shoals in Yunnan. They then come back to the Qinghai-Tibet Plateau the next March， April， and May to mate and breed. What interests biologists most is that they can fly over the himalayas during migration.

The bar-headed goose can fly as high as 6，000 to 10，000 meters and eagles and falcons can fl y only 3，000 to 7，000 meters high， with it being needless to say that most birds fl y no more than 1，000 meters. The oxygen content over the peak of Mt. Qomolangma is no more than 30 percent of that at sea level， but how are the bar-headed geese able to fl y over the highest mountain in the world？

First， the bird has a physiologic structure that fi ts to the life on the highland. Study results show that the bar-headed goose has a variant hemoglobin that combines oxygen faster， and it has more blood capillaries than other birds. Its stronger respiratory function helps it increase the net oxygen content into the blood. You cannot but admire that parent bar-headed geese have the foresight to breed and bring up their off spring on the Qinghai-Tibet Plateau at altitudes of more than 4，000 meters， and the younglings win at the starting line before they are born.

Second， the bird receives benefits from “its roller coaster flight mode”， speaking of when it flies over the Himalayas and comes close to the earth， across the peaks and valleys like a roller coaster running through its ascending and descending track. A research team from Bangor University has tracked the flock migration and finds that the heart of a bar-headed goose beats faster as the altitude gets higher， and it therefore concluded that compared to high-altitude fl ight， this roller coaster flight mode saves physical strength.

Besides this， the earlier study shows that bar-headed geese often feed in the day and fly at night， maybe because it is colder with denser air at night.

Compared to star species like the Tibetan antelope and wild blacknecked crane on the Qinghai-Tibet Plateau， the bar-necked goose is not that attractive， so much so that the bird’s population has been prosperous since long before. However， as tourism has started to develop on the highland， some herdsmen， driven by profit， have begun to snatch up their eggs and sell them to restaurants as a special food to cater to tourists. It is requested that you do not eat them if you come to the Qinghai-Tibet Plateau， because each egg contains a fl uff y bar-headed goose chick within it.