But during the breeding period, they spread out over a much larger region, including over diverse habitats like farmlands, semi-arid areas and marshlands.Ĭuriously, the birds didn’t necessarily visit the same place every year to breed. Those birds that spent their post-breeding season in and around Delhi restricted themselves to a smaller area, mostly in the vicinity of rubbish dumps, abattoirs, slaughterhouses and other animal-processing facilities. The researchers also recorded the spread of the breeding area and the region where black-eared kites spent the winter. So if they had chosen to cross the Himalaya directly, along the shortest route, they might have been forced to fly continuously over mountain ranges and desert for about 1,500-2,000 km. The paper describing their study noted that the south-westerly winds could displace the birds farther east. The researchers have reasoned that the birds took this somewhat circuitous route to avoid harsh weather and for the favourable winds. However, the researchers found that three kites travelled even further west, through eastern Pakistan, Afghanistan, Tajikistan and Kyrgyzstan, to reach the same destination. Many even flew by the K2 peak – the second-highest in the world. Most birds crossed over the Himalaya by the Karakoram range at over 6,500 m above sea level. It is adjacent to western Kazakhstan, southern-central Russia, western Mongolia and north-western China. These made up a large swath of land in and around the Altai mountain range, some 85-times larger than the area the birds covered in and around Delhi. ![]() ![]() The migration routes the birds took were largely similar before and after breeding.Īt the start of their breeding season, these raptors travelled northwest from Delhi, crossed the Himalaya over their western portion – between Punjab and Jammu & Kashmir – and soared through or circumvented the Taklamakan desert and China’s Tian Shan mountain range, to reach their breeding grounds. So in two to seven weeks, they could fly 3,300-4,800 km. The kites roosted at night and travelled during the day, from 150 km to 240 km before nightfall. ![]() Most notably, the researchers found that the kites used the Central Asian Flyway, a route that has been well-appreciated for some flapping birds like ducks and geese, but not for soaring birds. Yossi Leshem, a professor of zoology at Tel Aviv University, studies the migration of soaring birds, and he said the quantitative work and separation between immature and adult birds was quite impressive. “It is notable for two reasons, to my mind – the large number of individuals systematically tracked, and that this is one of the very few studies of a species other than waterbirds in India.” “This is a remarkable study that adds tremendously to our knowledge of bird migration,” Suhel Quader, a senior scientist at the Nature Conservation Foundation, Bengaluru, told The Wire Science. This way, the researchers found, the kites seem to cross over the Karakoram range. The researchers tagged 19 kites – 14 adults and five pre-adults – with GPS trackers to reveal their routes. In a recent study published on September 29, scientists from the Wildlife Institute of India (WII), Dehradun, the University of Oxford and the Doñana Biological Station, Seville, tracked the migration of black-eared kites to and from Delhi, flying over nine Asian countries. In fact, scientists continue to be intrigued by how and where these birds cross the Himalayan barrier. While some ornithologists have studied the migration of waterbirds that flap across the Himalaya to get to India, the raptors’ routes have been less known. One of them is the black-eared kite, a bird of prey, also called a raptor, that breeds in central-northern Asia, and spends its winter in multiple parts of South Asia, including in and around Delhi. Over 229 species of migratory birds spend their winters in the Indian subcontinent. These migrants journey along one of the world’s nine major flyways – the patterned routes in the sky that birds take – to reach their destinations. ![]() Now is quite the season for bird-watchers in the tropics, as they welcome thousands of migratory birds flying towards their winter homes. Photo: nubobo/Wikimedia Commons, CC BY 2.0. A black kite, of which the black-eared kite is a subspecies, takes flight somewhere in Japan, January 2014.
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