|A tiger caught on camera during the study.
Picture courtesy WWF-India and Sunderban Biosphere Reserve
The early findings of a tiger study in the Sunderbans based on the advanced camera-trapping technique suggest that there could be at least 100 Royal Bengal Tigers in the mangrove forest, more than the figure a previous sample count had thrown up.
“The camera-trapping study is continuing since November. Early trends indicate that the Sunderbans must be having at least 100 tigers,” said S.B. Mondal, the head of the forest force and former chief wildlife warden.
The national tiger census in 2010 had put the Sunderbans count at 64-90 — 70 being the most likely figure.
Of the four Sunderbans ranges, WWF-India is conducting the study in three — Sajnekhali, National Park East and Basirhat — and WII (Wildlife Institute of India) in the fourth, National Park West.
“The study in Sajnekhali and National Park East is over. The final figures will be collated in another two months, once the count from the other two ranges comes in,” a forest official said.
The organisations were using one of the most advanced techniques — camera trapping — to get an authentic tally. At least 55 pairs of cameras have been installed at strategic locations in each of the four ranges.
The cameras have heat and motion sensors to detect and film an object moving between a pair of cameras installed around 30 feet from each other. When the sensors detect a motion, the cameras take still photographs. If the object remains within the sensor range, a 30-second video clip is taken.
“It is expected that the number of cameras and the area covered will enable us to locate most of the tigers as well as other animals. This will also help us get a fair idea of the number and variety of prey for the big cats,” the official said.
“Chances are the maximum number quoted in the 2010 census (90) can be the minimum this time, though we have yet to receive and analyse all the data covering the entire reserve,” Anurag Danda, the head of WWF-India’s Sunderbans chapter, said.
A similar study carried out last year by WWF in the South 24-Parganas stretch of the Sunderbans — not within the tiger reserve — found 20 tigers.
The 2010 census used camera trapping but in select areas. The results were expanded to cover the whole of the tiger habitat on the Indian side. The 2000 and 2004 censuses, in contrast, followed the traditional and tedious exercise of counting pugmarks.
The 2000 count was 274 tigers and the next one, 271.
The stills and videos from the current study challenged the latest assumption that Sunberbans tigers have shrunk in size because of dwindling prey. “It’s a misconception. The photographs are proof that the animals are of normal build. In fact, some are quite huge,” Mondal said.
It has also been found that a wide range of tiger food such as spotted deer and wild boars was available. This contradicted the opinion that lack of prey in the forests was forcing tigers to stray into human habitation.
Danda said overlapping of tiger ranges has forced the old and weak tigers to enter human settlements in search of easy prey such as livestock and people. “A detailed study can find out the exact reasons for tigers turning maneaters.”