Certain species of eagles and hawks prefer the Khyber Pass or other low- altitude areas while migrating from their breeding grounds in central Asia and Russia to their wintering grounds in India and other Asian countries across the Himalayas and the Hindu Kush ranges, a study by the Sasan wildlife division of the Gujarat forest department has revealed.
The findings have been reported in a research paper published in the latest issue of Birds, a peer-reviewed international journal published by Basel-based MDPI.
There are 557 known species of raptors or birds of prey such as hawks, eagles, vultures, kites and falcons of which 18 per cent species face extinction, while the population of 52 per cent are on the decline. Most of the threatened species of raptors occur in Asia and many of them use the Central Asian flyway (CAF) for migrating to warmer climes (a country with a particular kind of climate) of South Asia during the winter, to escape the harsh weather of their breeding grounds in central Asia and Russia. They undertake their spring migration or return migration in March-April at the onset of summer in south Asia to avoid the extreme heat.
To study the raptors’ breeding and wintering grounds and their migration routes and patterns, the Sasan wildlife division of the Junagadh wildlife circle tagged four birds— greater spotted eagle (GSE), a male pallid harrier (PHR), Indian spotted eagle (ISE) and tawny eagle (TWE)—in February-March last year with solar-powered satellite tags. While GSE, ISE and PHR were tagged as they were wintering in Junagadh, the TWE was tagged in Kutch.
The tagged GSE flew 5,696 kilometres in 13 days to go to its breeding grounds in Kazakhstan via Pakistan, Afghanistan, Tajikistan and Uzbekistan. In its return migration, it flew to Pakistan via Uzbekistan, Turkmenistan and Afghanistan and established a winter home in Pakistan, covering 2,450 kms in just three days.
Similarly, the tawny eagle flew 3,740 kms in 11 days along a similar route to reach Kazakhstan and 2,740 kms in 22 days to return to Rajasthan. The pallid harrier undertook the longest migration—flying 11,999 kms to reach Russia in 34 days via Pakistan, Afghanistan, Turkmenistan, Uzbekistan and Kazakhstan. It flew back 9,021 kms along the same route and reached Pakistan in 52 days before its satellite tag stopped transmitting data from October 10, 2021.
ISE, on the other hand, flew 1,565 kms in two days to go to Punjab province in Pakistan and 1,365 kms in a day to return to Gujarat. The Himalayas and the Hindu Kush form the great natural barrier between central Asia and the Indian subcontinent and species like bar-headed goose and some cranes are believed to fly over the peaks of Himalayas during their annual migrations. However, while analysing the telemetry data transmitted by the satellite tags, Mohan Ram, deputy conservator of forests (DCF) of Sasan wildlife division, and other researchers observed that the tagged raptors avoided the high-altitude Himalayas and Hindu Kush mountain ranges while migrating from their wintering grounds and back.
The researchers observed that the tagged GSE and TWE used the Khyber Pass for crossing the high Himalayas in north-east Pakistan and the Hindu Kush in east-central Afghanistan.
Once past the great barrier, they flew north-eastward to go to their breeding grounds in Kazakhstan. Both species used almost similar paths for their autumn migration to arrive in the Indian sub-continent, the researchers observed.
On the other hand, pallid harrier, the bird of hawk sub-family and the smallest of the four tagged species, preferred to skirt the western tip of the Hindu Kush in the north-western Afghanistan before diverting north-east to go to Russia and returned to Pakistan through the same route, the researchers observed.
ISE was also observed to be spending the summer in Punjab province of Pakistan from late April while returning to Bikaner in Rajasthan in late November.
Besides Ram, others who were part of the study include Shyamal Tikadar, then chief wildlife warden of Gujarat, Aradhna Sahu, the chief conservator of forests of Junagadh wildlife circle, Devesh Gadhvi, deputy director of Corbett Foundation, Tahir Ali Rather, Lahar Jhala and Yashpal Zala. “Our study also reports the first record of the winter and summer home range of the Indian Spotted Eagle in Pakistan. The tagged raptor used low elevation flyways than the straighter northern flyways over the Himalayan Mountain range, as found in another earlier study,” the paper quotes the researchers as reporting.
T Ganesh, a raptor researcher with the Bengaluru-based Ashoka Trust for Research in Ecology and the Environment (ATREE) and who has been studying migrating grassland raptors, said the Gujarat government’s research is a good “indicative” study. “There is no tracking of birds that pass through the Khyber Pass and that way, this particular study is quite novel. There have been some anecdotal records of the birds using the Khyber Pass for crossing the Himalayas,” he said.
However, he said the sample size is an issue. “If you really want a scientifically rigorous study, you need to increase the sample size because one bird might have used the Khyber Pass, another bird of the same species could probably go the different way. So, it’s difficult to generalise on the basis of movement of just one individual. Nonetheless, this study is indicative of the routes these might be taking.”