Thiruvananthapuram: On International Tiger Day, Kerala seems to be in a position to boast of its tiger conservation exploits. There has been a dramatic increase in the state's tiger population. From 71 in 2010, the number of tigers in the state has shot up to 180, a population growth of 153 per cent in about five years.

Fact is, 180 is an old number, the figure arrived at in 2016. The state's tiger population in 2018 will be clear only after two months, after the latest camera-trap images are processed.

However, 180 is not the number of tiger images that the state's camera traps had captured during a five- to six-month period. “That would be somewhere near 10,000,” said Georgi P Mathachen, the field director of Periyar Tiger Reserve. “From those surfeit of images, after a laborious identification process, we had identified 180 distinct tigers,” he said. One tiger is differentiated from the other on the basis of the yellow and dark stripes on its body. Like the whorls on a human thumb, each tiger has a unique stripe pattern.

Nonetheless, Mathachen concedes that 180 is an approximation. “Among the 180 there could be tigers from other-state reserves,” he said. This cross-border movement is especially high in Wayanad Wildlife Sanctuary that borders the Bandipur national park and Nagarhole national park in Karnataka, and Mudumalai Tiger Reserve in Tamil Nadu. This, in a way, could explain why Wayanad has 84 tigers, the largest in the state. Periyar Tiger Reserve has 29 and Parambikulam, 31.

“But even if you subtract some saying they had crossed over from the borders, it will be more or less made up if we consider the fact that the camera-trap system is not that strong in ordinary forest divisions were tiger sightings have increased in the last few years. So where we have estimated just one or two tigers, the actual population could be somewhere around 10,” Mathachan said. In short, the field director said that 180 was a very close approximation.

A national trend

The increase in tiger population seems to be a national trend. “Preliminary indications from the on-going countrywide tiger census point to the possibility of an increase in the number of tigers,” union minister for environment, forest, and climate change Dr Harsh Vardhan said at a function to mark the Tiger Day in New Delhi on Sunday. The 2016 figures show that India has 2,226 tigers, 1,793 tigers more than Russia, the country with the second highest population of tigers in the world. India also holds nearly 60 per cent of the world's tigers.

However, the PTR field director plays down the dramatic growth in tiger numbers. “I think, at least in Kerala, the population has been steady over the years. It is just that our process of estimation has become more accurate,” Mathachen said. Before the Sariska controversy erupted in 2005, pugmark census was the in thing. Tiger numbers were ascertained on the basis of the pugmarks found on forest soil. The method was found utterly unreliable after all the 18 tigers in Sariska Tiger Reserve in Rajasthan vanished without a trace in the last five months of 2004.

From then on, camera traps were adopted as a more scientifically and logically sound mechanism of assessing tiger numbers. Since Kerala has a forest area of nearly 20,000 sq kms, it is not possible to have camera traps installed at all crucial points. So camera traps are not permanently fixed, they are moved around.

It is a three-day process to identify the place where the traps have to be mounted in the first place. First, a random block is selected and field officers move around the place looking for telltale tiger signs like pugmarks, poo or scat, and scratch marks on tree barks. It is based on the density of these marks that a decision is made to install camera traps in a particular area or not. A week later another block is found, and the traps are moved to that place.

Read more: Latest Kerala news