Kaustuv Chatterjee
18-03-2014, 01:14 PM
The summer habitat is high-altitude lakes where the bird grazes on short grass. The species has been reported as migrating south from Tibet, Kazakhstan, Mongolia and Russia before crossing the Himalaya. The Bar-headed Goose is one of the world's highest-flying birds, having been heard flying across Mount Makalu – the fifth highest mountain on earth at 8,481 m (27,825 ft) and apparently seen over Mount Everest – 8,848 m (29,029 ft) – although this is a second-hand report with no verification. This demanding migration has long puzzled physiologists and naturalists: "there must be a good explanation for why the birds fly to the extreme altitudes... particularly since there are passes through the Himalaya at lower altitudes, and which are used by other migrating bird species." In fact, bar-headed geese have never been directly tracked (using GPS or satellite logging technology) flying higher than 6,540 metres (21,460 ft), and it is now believed that they do take the high passes through the mountains. The challenging northward migration from lowland India to breed in the summer on the Tibetan Plateau is undertaken in stages, with the flight across the Himalaya (from sea-level) being undertaken non-stop in as little as seven hours. Surprisingly, despite predictable tail winds that blow up the Himalayas (in the same direction of travel as the geese), bar-headed geese spurn these winds, waiting for them to die down overnight, when they then undertake the greatest rates of climbing flight ever recorded for a bird, and sustain these climbs rates for hours on end, according to research published in 2011.
Shot with the Nikon D 90, Nikkor 300mm f4 + 1.4 TC, at 420 mm, ISO 400, 1/800s - F/7.1, -0.3EV.
Shot with the Nikon D 90, Nikkor 300mm f4 + 1.4 TC, at 420 mm, ISO 400, 1/800s - F/7.1, -0.3EV.