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Mysteries of the flyways
Siba Mohanty
First Published : 06 Feb 2010 12:30:00 AM IST
Last Updated : 05 Feb 2010 07:37:22 PM IST
Centuries ago, Aristotle had obse*rved the cranes and their seasonal disappearance with great curiosity; in 1970, Richard Bach created out of a gentle seagull a modern day classic on man?s quest for the never-ending pursuit of excellence. It was a yellow-throated sparrow that gave India its legendary ?birdman? Salim Ali.
Down the ages, mankind has looked up to birds for inspiration. They have remained a metaphor for mysticism.
Their migration has confounded them all ? writers, philosophers and scientific community alike. Do they use the magnetic field of the earth to find their way across the continents? Or is it their olfactory nerves which help them with a map of the earth? What explains the trait of ?homing?? Do they return to the same wintering ground showing a trait which the ornithologists call ?habitat fidelity??
In fact, scientists sometimes have found more questions than answers. A Manx Shearwater, a sea bird seen on the shorelines of UK, was ringed in 1953 and found to have lived for over 50 years, one of the oldest living sea birds. One of them was reported to have flown a mindboggling five million miles during its lifespan, as recorded by British ornithologist Chris Mead in 2002.
Not surprising that the birds have been under intense scrutiny over the years for their uncanny ability to fly long distance. A few years ago when the deadly avian influenza broke out, the scientists decided to go to the birds again. This time, the idea was to observe if the H5N1 virus was being transmitted by the wild birds of Asia.
In the Qinghai lake of China, in 2005, large scale mortality of wild birds alerted the scientific community because the wetland was a hunting ground for thousands of migratory species. This soon was followed by avian influenza outbreak among poultry in Xinjiang Autonomous Region and an alarm was raised when research detected, from viruses isolated from dead birds in Qinghai lake, a new H5N1 strain that could be fatal for wild birds. The FAO and US Geological Survey (USGS) with their global partners then decided to launch satellite tracking of migratory birds in 2008.
As part of the project in India, a team of international scientists gathered at Chilika lagoon in Orissa which happens to be amongst the largest wintering grounds for migratory birds in the subcontinent where they sampled water birds and marked them with satellite tags in December the same year. Similarly, birds from Koothankulam Bird Sanctuary, near Tirunelveli in Tamil Nadu, were sampled too. The researchers then tracked the 70 satellite-collared birds to understand if there exists a correlation between the locations of these marked birds and the avian influenza outbreak along their migratory pathways, known as flyways.
?The objective was to understand both ? movement of avian influenza viruses and other diseases in the Central Asian Flyway and improve understanding of the ecological habits of water birds. Also the interaction among wild and domestic birds could be understood,? says Dr Ajit Kumar Patnaik, Chief Executive of Chilika Development Authority.
A year later, the first available results have thrown light not only on the pathways of the wild birds and the H5N1 virus connection but contributed to the existing pool of study on migration behaviour of the winged visitors in this part of Asia. It was also for the first time that birds at Chilika were made part of such a project.
?The study established linkages between Chilika and the breeding grounds in China and Mongolia where avian influenza outbreak was reported. From here, they travelled to those farthest northern places where the virus had been detected,? says Dr S Balachandran of Bombay Natural History Society (BHNS). Seven of the 15 bar-headed geese released from Chilika and six out of 10 collared at Koothankulam reached their breeding grounds in the next few months.
In their northward direction, the geese covered a distance of over 5,670 km with a non-stop flight of about 1,144 km over an 89 hour period. Stopping over Andhra Pradesh, Orissa, Chhattisgarh, West Bengal, Bihar and Sikkim along their way, they also hopped at Nepal, Bangladesh, Bhutan, Tibet and China. Over the Himalayas, they achieved a flying height of 21,400 ft. In the past, these geese have been reported to be flying over the highest peak of 29,000 ft and the current study comes close to establish it.
Similar was the tracking result of the Brahminy Shelduck. Released from Chilika on December 10, 2008, it was tracked all along till it reached China a good nine months later in the next September. Two other species ? Northern Shoveler and Garganey ? too made to their breeding grounds in Tibet and were tracked successfully by the researchers when they passed through Kyrgyzstan and Tajikistan.
Since the birds were marked with GPS with solar-powered platform terminal transmitters (PTTs) programmed to record the location every two hours, the study revealed that the northern migration route of the Chilika birds consists of extremely dry regions. ?We found out that birds such as Gadwalls and Eurasian Wigeons use Chilika as their moulting ground while the bar-headed geese gained weight upto 705 grams (stored fat) so that it could survive the long flights to the northern hemisphere,? Balachandran points out.
While there have been debates over the return migration route of the birds, the satellite tracking saw the geese taking a similar pathway on their way back the next winter in 2009. The return migration also proved that the migrating birds have a ?habitat fidelity? which means they return to the lagoon year after year taking the same flyway, using the similar route and utilising the same wetlands on their way.
Interestingly, when they had started their farthest north sojourn in 2008, en route the northern hemisphere the bar-headed geese had found their way to West Bengal?s Malda and Purulia where avian influenza outbreak was reported. It clearly establishes that these birds moved through the avian influenza outbreak regions. However, no migratory has been tested positive for H5N1 yet.
What?s the Central Asian flyway
The CAF range is essentially centred on one of the three major wintering areas of waterfowl in the Old World, namely the Indian subcontinent, the other two being Africa, in territory of the African-*Eurasian Flyway (AEWA) to the west, and South-east Asia in the East Asian-Australasian Flyway (EAAF) to the east. These wintering areas are geographically separate, and present entirely different ecological, historical and cultural situations.
The flyway covers 30 countries of North, Central and South Asia and Trans-Caucasus. The northern catchment area of CAF inevitably overlaps, and considerably overlaps, with both those of AEWA and EAAF, mostly within a single country, the Russian Federation, though sixteen of the 30 countries encompassed by the CAF are located in the AEWA area.
? sibamohanty@expressbuzz.com
Mysteries of the flyways
Siba Mohanty
First Published : 06 Feb 2010 12:30:00 AM IST
Last Updated : 05 Feb 2010 07:37:22 PM IST
Centuries ago, Aristotle had obse*rved the cranes and their seasonal disappearance with great curiosity; in 1970, Richard Bach created out of a gentle seagull a modern day classic on man?s quest for the never-ending pursuit of excellence. It was a yellow-throated sparrow that gave India its legendary ?birdman? Salim Ali.
Down the ages, mankind has looked up to birds for inspiration. They have remained a metaphor for mysticism.
Their migration has confounded them all ? writers, philosophers and scientific community alike. Do they use the magnetic field of the earth to find their way across the continents? Or is it their olfactory nerves which help them with a map of the earth? What explains the trait of ?homing?? Do they return to the same wintering ground showing a trait which the ornithologists call ?habitat fidelity??
In fact, scientists sometimes have found more questions than answers. A Manx Shearwater, a sea bird seen on the shorelines of UK, was ringed in 1953 and found to have lived for over 50 years, one of the oldest living sea birds. One of them was reported to have flown a mindboggling five million miles during its lifespan, as recorded by British ornithologist Chris Mead in 2002.
Not surprising that the birds have been under intense scrutiny over the years for their uncanny ability to fly long distance. A few years ago when the deadly avian influenza broke out, the scientists decided to go to the birds again. This time, the idea was to observe if the H5N1 virus was being transmitted by the wild birds of Asia.
In the Qinghai lake of China, in 2005, large scale mortality of wild birds alerted the scientific community because the wetland was a hunting ground for thousands of migratory species. This soon was followed by avian influenza outbreak among poultry in Xinjiang Autonomous Region and an alarm was raised when research detected, from viruses isolated from dead birds in Qinghai lake, a new H5N1 strain that could be fatal for wild birds. The FAO and US Geological Survey (USGS) with their global partners then decided to launch satellite tracking of migratory birds in 2008.
As part of the project in India, a team of international scientists gathered at Chilika lagoon in Orissa which happens to be amongst the largest wintering grounds for migratory birds in the subcontinent where they sampled water birds and marked them with satellite tags in December the same year. Similarly, birds from Koothankulam Bird Sanctuary, near Tirunelveli in Tamil Nadu, were sampled too. The researchers then tracked the 70 satellite-collared birds to understand if there exists a correlation between the locations of these marked birds and the avian influenza outbreak along their migratory pathways, known as flyways.
?The objective was to understand both ? movement of avian influenza viruses and other diseases in the Central Asian Flyway and improve understanding of the ecological habits of water birds. Also the interaction among wild and domestic birds could be understood,? says Dr Ajit Kumar Patnaik, Chief Executive of Chilika Development Authority.
A year later, the first available results have thrown light not only on the pathways of the wild birds and the H5N1 virus connection but contributed to the existing pool of study on migration behaviour of the winged visitors in this part of Asia. It was also for the first time that birds at Chilika were made part of such a project.
?The study established linkages between Chilika and the breeding grounds in China and Mongolia where avian influenza outbreak was reported. From here, they travelled to those farthest northern places where the virus had been detected,? says Dr S Balachandran of Bombay Natural History Society (BHNS). Seven of the 15 bar-headed geese released from Chilika and six out of 10 collared at Koothankulam reached their breeding grounds in the next few months.
In their northward direction, the geese covered a distance of over 5,670 km with a non-stop flight of about 1,144 km over an 89 hour period. Stopping over Andhra Pradesh, Orissa, Chhattisgarh, West Bengal, Bihar and Sikkim along their way, they also hopped at Nepal, Bangladesh, Bhutan, Tibet and China. Over the Himalayas, they achieved a flying height of 21,400 ft. In the past, these geese have been reported to be flying over the highest peak of 29,000 ft and the current study comes close to establish it.
Similar was the tracking result of the Brahminy Shelduck. Released from Chilika on December 10, 2008, it was tracked all along till it reached China a good nine months later in the next September. Two other species ? Northern Shoveler and Garganey ? too made to their breeding grounds in Tibet and were tracked successfully by the researchers when they passed through Kyrgyzstan and Tajikistan.
Since the birds were marked with GPS with solar-powered platform terminal transmitters (PTTs) programmed to record the location every two hours, the study revealed that the northern migration route of the Chilika birds consists of extremely dry regions. ?We found out that birds such as Gadwalls and Eurasian Wigeons use Chilika as their moulting ground while the bar-headed geese gained weight upto 705 grams (stored fat) so that it could survive the long flights to the northern hemisphere,? Balachandran points out.
While there have been debates over the return migration route of the birds, the satellite tracking saw the geese taking a similar pathway on their way back the next winter in 2009. The return migration also proved that the migrating birds have a ?habitat fidelity? which means they return to the lagoon year after year taking the same flyway, using the similar route and utilising the same wetlands on their way.
Interestingly, when they had started their farthest north sojourn in 2008, en route the northern hemisphere the bar-headed geese had found their way to West Bengal?s Malda and Purulia where avian influenza outbreak was reported. It clearly establishes that these birds moved through the avian influenza outbreak regions. However, no migratory has been tested positive for H5N1 yet.
What?s the Central Asian flyway
The CAF range is essentially centred on one of the three major wintering areas of waterfowl in the Old World, namely the Indian subcontinent, the other two being Africa, in territory of the African-*Eurasian Flyway (AEWA) to the west, and South-east Asia in the East Asian-Australasian Flyway (EAAF) to the east. These wintering areas are geographically separate, and present entirely different ecological, historical and cultural situations.
The flyway covers 30 countries of North, Central and South Asia and Trans-Caucasus. The northern catchment area of CAF inevitably overlaps, and considerably overlaps, with both those of AEWA and EAAF, mostly within a single country, the Russian Federation, though sixteen of the 30 countries encompassed by the CAF are located in the AEWA area.
? sibamohanty@expressbuzz.com