Unexpected have been the findings with a common, small migratory bird, along with an insight on maturity and experience versus young and brash! It is an extraordinary tale of endurance, taking on the formidable Himalaya mountain range with its extreme elevations, without conveniently flying around it, by two innocuous Brown-headed Gulls, when usually this challenging [...]
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Unexpected have been the findings with a common, small migratory bird, along with an insight on maturity and experience versus young and brash!
It is an extraordinary tale of endurance, taking on the formidable Himalaya mountain range with its extreme elevations, without conveniently flying around it, by two innocuous Brown-headed Gulls, when usually this challenging journey is undertaken only by a few large bird species.
Adult ‘Hima Kumari’ and sub-adult ‘Sherpa Tenzing’
This tale is of mature adult ‘Hima Kumari’ (Snow White) and brash sub-adult ‘Sherpa Tenzing’, laughs Professor Sampath Seneviratne of the Avian Sciences and Conservation Laboratory of the Department of Zoology and Environment Sciences of the University of Colombo.
He revealed these findings at a lecture to the Sri Lanka Natural History Society on June 11.
While Snow White is the main character in the famous fairy tale, Sherpa Tenzing has been named after the Nepali-Indian Sherpa mountaineer who with Edmund Hillary became the first to set foot on the summit of Mount Everest back in 1953.
Earlier, it had been thought that only bigger birds such as the Bar-headed Goose (2-3kg) usually flying high at 23,000ft; the Demoiselle Crane (2-3kg) at around 26,000ft; and the Steppe Eagle (2.4-3.9kg) at around 23,600ft, took on the mighty Himalayas.
Prof. Sampath Seneviratne and Dr. Gayomini Panagoda with 'Hima Kumari'
This was an incredible contrast – Hima Kumari weighing only around 500g and Sherpa Tenzing around 490g did cross the arduous elevations.
Brown-headed Gulls, about ¼ in weight compared to the other species which undertake this quest, are likely to be one of the “lightest” species to cross the Himalayas, says Prof. Seneviratne.
Hosting the highest peaks on earth including the awe-inspiring Mount Everest, the Himalayas are a massive, active mountain system stretching around 2,500 km across Asia. It forms a natural border between the Indian subcontinent and the Tibetan Plateau, spanning Pakistan, India, Nepal, Bhutan and China (Tibet).
Before talking about these amazing findings with regard to ‘flights’ over the Himalayas, Prof. Seneviratne looks at why these flight paths are necessary…….This is the range that the birds in the Northern Hemisphere have to overcome in their search for warmer climes during the bitter cold winter and is part of animal migration. It is the long-distance movement of individual animals – found in all major animal groups including birds, mammals, fish, reptiles, amphibians, insects and crustaceans – usually on a seasonal basis.
This records how Brown-headed Gulls travel between their breeding grounds in Tibet and their wintering grounds in Mannar
Birds enjoy the massive and lush land mass with little human habitation in the Northern Hemisphere during the summer months with 18-20 hours of daylight. It is here that they breed and raise their families. During this period, the Southern Hemisphere is cold. However, as the sun moves south and the Northern Hemisphere is covered by a mantle of darkness and snow, the birds move to the Southern Hemisphere, in search of warmer climes, fresh water and food, using specific routes, says Prof. Seneviratne.
Dubbing ‘Bird Migration’ as the greatest dance on the planet, he explains the main global migratory routes as: Pacific Americas; Central Americas; Atlantic Americas; East Atlantic; Mediterranean Black Sea; East Asia/East Africa; Central Asian; and East Asian-Australasian flyways.
Next he focuses on the landlocked ‘Central Asian Flyway’ with its series of ecological barriers for migration – the Central Siberian Plateau (CSP), the South Siberian Mountains (SSM), the Tien Shan (TS), the Steppe & Desert (S&D), the Qinghai Tibetan Plateau (QTP) and the Himalayan ridge.
Creating the image of birds “funnelling” down to Sri Lanka, he talks of how this country gets lots of migrants because “we are the southern-most terminus” and beyond is the driest, windiest, coldest Antarctica, covered in thick ice.
Immensely proud of Sri Lanka’s strategic position in the Central Asian Flyway, similar to the Silk Road of yore, this Zoologist says that Eurasia holds 2/3rds of the world’s migrant birds, around 1,600 species. The total number of species in Sri Lanka is 500, with 250 ‘residents’ (35 endemics) and a sizable 250 ‘migrants’.
From 2020 in Mannar, Prof. Seneviratne and his team including Dr. Gayomini Panagoda have been carrying out GPS/GSM tracking of migrant birds to characterize Sri Lanka’s role in global migration under a collaborative project with the Research Center for Eco-Environmental Sciences, the Chinese Academy of Sciences, Wetlands International, Palmyrah House and the Field Ornithology Group of Sri Lanka (FOGSL).
GPS or Global Positioning System is a satellite-based navigation system, while GSM or Global System for Mobile communications, is digital mobile network technology. The tracking devices used were Druid, Debut Mini, Debut Lego, HQXS and HQBG tags.
Of the 70 tags deployed, one each was for Hima Kumari and Sherpa Tenzing.
The data collected were: Location-based data – latitude, longitude, altitude, speed & course (interval of collection – 2 hrs); Environmental data – temperature, light intensity & voltage (interval of collection – 30 mins); and Animal behaviour data – ODBA or Overall Dynamic Body Acceleration, used to quantify an animal’s physical movement and energy expenditure (interval of collection – 30 mins).
Looking back, Prof. Seneviratne says they tracked the Brown-headed Gulls Hima Kumari and Sherpa Tenzin (in April 2021 and March 2022 respectively) and the Heuglin’s Gulls Manike, Megha and Mary (the first two in April 2021 and the other in March 2022 respectively). The team had also tracked the Crab Plovers, nicknamed Ali, Kira, Raja and Sindbad.
All these were among a diverse group of 11 species of water birds which also included 1 Arctic Skua; 2 Caspian Terns; 2 Lesser Crested Terns; 2 Eurasian Wigeons; 1 Grey Plover; 1 Common Redshank; 1 Whimbrel and 1 Eurasian Curlew.
The taggings have given the team valuable insights into the patterns of migratory water birds’ local movement in areas such as the Adam’s Bridge Marine National Park; the Urumalei mudflat & Rama’s Bridge; the Erukkalampiddy lagoon; the Vankalei Sanctuary; and the Wedithalathive Nature Reserve.
They have also mapped major movement corridors within the Palk Bay-Gulf of Mannar; among the critical wetlands in Mannar; and within Sri Lanka.
“The Central Asian Flyway connects Sri Lanka to the world and this is how an estimated 15 million birds come to us – it’s a great gathering, a place where two hemispheres interchange,” adds Prof. Seneviratne.
Mature Hima Kumari is the first known Brown-headed Gull to cross this range on her northward journey to her breeding grounds in Tibet’s Angzicuo Lake. She had departed Mannar on April 25, 2021 and reached the Tibetan Plateau by May 3. Flying over 18,000ft, she had made the Brown-headed Gull the lightest species to reach such extreme altitudes. The distance covered was 2,786km, with no stopovers except resting along the Ganges in Bihar for 32-42 hours.
Her maturity and experience, as opposed to the daredevil Sherpa Tenzing is seen in that Hima Kumari flew between the peaks of Manaslu (26,800ft) and Nemjung (23,500ft) rather than over them.
In her southward migration later in 2021, Hima Kumari had departed the Tibetan Plateau on October 6, with two stopovers in India – 8 days in Alibag beach, Maharashtra, and 5 days at the Kali river estuary in Karnataka. She had arrived in the north of Sri Lanka on December 19.
“This is loop migration,” says Prof. Seneviratne, explaining how Hima Kumari used a circular travel pattern to come down to Sri Lanka and instead of using the same route took a different one back to her breeding grounds.
Brash Sherpa Tenzing, meanwhile, crossed the Himalayan peaks just 20km west of Mt. Everest, on the way to his Tibetan breeding grounds of Gerencuo Lake. It took him just 4.5 days during which he flew 4,840km, from the sea level in Mannar to 24,930ft up in Tibet.
Not for him the fainthearted flying in-between peaks, as he scaled the Peak of Cho Oyu, crossing an altitude of 19,500 ft, very close to Everest, earning his name from the team.
Prof. Seneviratne raises a point of interest – long haul passenger jets fly at around 30,000ft but have oxygen in the cabins, while humans who scale Everest carry their own oxygen. These birds, however, overcome the issue of getting hit by a lack of oxygen by flying quickly to reduce the time duration. Share This Post Tweet Facebook Twitter Email × Send Email to Friend
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