Camera, collars, mark count of Sundarban tigers

Sundarbans, the largest estuarine mangrove forest in the world, also boasts of the highest number of tigers in the country. Now enumerators are carrying out the arduous task of counting the big cats in nearly 1,600 sq km of inhospitable forest terrain.

With access to the Sundarban forests being problematic -- the islands are separated by tidal creeks -- wildlife scientists asked for a separate census in the region involving the use of advanced techniques like camera trapping, satellite tracking and radio telemetry, whereby tigers are radio collared.

“Sundarbans is a very difficult terrain and tiger scats (droppings) would be collected for DNA sampling to arrive at a more accurate count,” Pradeep Vyas, the director of the Sundarban Biosphere Reserve, told IANS.

The DNA sampling of tiger scats is being used for the first time in Sundarbans.

The tiger census in Sundarbans began in early March with a preliminary round of data collection, using more effective counting methods. The exercise is slated to continue for three to four months more.

The 2006 census, the results of which were declared in 2008, put the country’s tiger population at 1,411. But Sundarbans were left out of that survey.

The 2001 census had put the number of tigers in the mangrove forests at over 200 -- the highest among all 28 reserves in the country.

The census area is divided into 100 compartments to be covered by over 250 personnel in 35 teams.

With data analysis to follow the census, the fresh tiger count in Sundarbans will not be known before the year-end.

Traditionally, tiger censuses have depended heavily on distinctive pug marks, but the method has faced much criticism for being error-prone.

The National Tiger Conservation Authority has laid down an improved counting system using the latest technology like satellite tracking and camera trapping of tigers.

In fact, one reason cited for the alarming drop in tiger numbers in 2008 is that the earlier counting methods may have resulted in inflated figures, which have been corrected subsequently.

Sundarbans’ uniqueness, stemming from its geography, presents unique challenges.

A Unesco World Heritage site and a Global Biosphere Reserve, here fresh water from the Ganga and salt water from the Bay of Bengal join together to create a special topography that is continuously in evolution.

The Royal Bengal Tiger of the Sundarbans too has developed unique characteristics.

Unlike tigers elsewhere, the ones in Sundarbans have become almost amphibious in nature, easily swimming the large tidal creeks separating the many local islands.

A good part of the Sundarbans tiger’s diet comprises aquatic creatures like fish, crabs and water lizards.

And it is Sundarbans’ distinct geography -- with features like tides, salt water and mangrove forests -- that is throwing up new challenges for the enumerators.

“We found that even the new technology for enumeration like radio collars on tigers and cameras trapping became useless when exposed to the salt water of Sundarbans,” says Vyas, who has been administering the precious eco-system for close to a decade.

Even as the census is under way, a torn radio collar detached from a tiger was found in the forests last month serving as a reminder of the difficulties.

“Our conservation tasks are particularly difficult because, unlike other forests, we cannot move around on foot but have to depend on boats to reach impenetrable swamps.”

“Another aspect of the difficult terrain is that nowhere else does the tiger defend its territory quite as aggressively,” says Vyas. This is a characteristic that has perhaps contributed to the “man-eater mystique of the Bengal tiger” acquired through the ages.

The Bengal tiger attacks aggressively, but from his experience, Vyas says, it is not a man-eater.

“Only one such case has been reported in Sundarbans -- more than 15 years ago,” he said.

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Printable version | Mar 2, 2021 4:10:59 AM | https://www.thehindu.com/sci-tech/energy-and-environment/Camera-collars-mark-count-of-Sundarban-tigers/article11875512.ece

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