The rise in tiger population in India is news to cheer for. But do you know how these ferocious and elusive wild cats are counted?
It is quite an uphill task involving tracking of tiger signs such as pug marks and scratch marks, using hi-tech cameras, DNA analysis and satellite telemetry.
The whole estimation process was conducted in three phases over one year between December 2009 and December 2010 and it involved more than 4.7 lakh forest officials, wildlife activists and volunteers.
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According to the Ministry of Environment and Forests, the “positive” results of the All-India Tiger Estimation study is the outcome of a tiresome enumeration exercise undertaken through a “best-in-class” scientific process.
Phase one of the Rs 9.1 crore-tiger estimation project included collection of field data at beat-level by trained personnel using a “standardised protocol“.
More than 45,000 sq km forest area of the country, including 39 designated tiger reserves, was divided in 29,772 beats or primary patrolling units.
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According to official data, a total of 4,76,000 forest personnel were involved in the data collection in phase one.
Besides trained forest officials, a number of wildlife activists and volunteers have also helped in the estimation exercise, said Dr Y B Jhala, senior wildlife biologist at the Wildlife Institute of India (WII) in Dehra Dun.
“In every beat, the officials had to walk at least 15 to 20 km a day to collect tiger habitation signs such as pug marks, scratch marks, their prey signs to assess the presence of the big cats,” said Dr Jhala, who coordinated the tiger census.
According to the ministry, the officials walked a total distance of 6,25,000 km for data collection.
The second phase of the estimation process involved analysing tiger habitat status by using satellite data.
In the third phase, hi-tech cameras were installed at strategic points like water bodies in the forests to collect information about the presence of the wild cats.
Through the camera trapping method, individual tigers were identified from photographs based on their unique stripe patterns and this information was analysed using “a well established scientific framework“.
Camera trapping was carried out by teams of wildlife biologists and local forest personnel and 880 camera traps were used covering an area of 10,500 sq km resulting in trapping 550 individual tigers during the whole process.
Satellite telemetry was used to track the beasts which were previously tagged with radio transmitters.
Among the other techniques involved in the counting process were DNA analysis, biometric data analysis, digital pug-mark prey base indicators, etc.