New Delhi, May 23: The threat to the big cat is bigger than estimated.

Tiger population has plunged in several reserves in central India, home to one of the largest concentrations of the national animal, according to the preliminary findings of a census.

The overall picture confirms the trends that have been trickling out over the last few weeks but the first glimpse of the reserve-by-reserve figures reveals that the crisis is more grave than previously assumed.

Individual figures for all states have not been given but it appears that in Madhya Pradesh, which has a third of the country’s tigers, the feline population has more or less halved.

The findings of the survey, done by the Wildlife Institute of India, are all the more alarming as the margin of error is narrow.

Armed with an improvised technique that combined different methods of counting tigers, the institute has enhanced accuracy.

Till the last census in 2002, tigers were only counted by pug marks. But this time, the institute also employed thousands of cameras in jungles to count tigers’ stripes.

The findings were cross-checked with other indicators — tiger sightings, the quality of prey base and the dung count. Like finger prints, pug marks and stripes are unique to a tiger and help in error-free identification.

The findings cover only some states — Madhya Pradesh, Rajasthan, Chhattisgarh, parts of Maharashtra, Andhra Pradesh and Orissa — but experts said they could be an indicator to the trend prevailing in other tiger territories.

Rajesh Gopal, member-secretary of the National Tiger Conservation Authority, said tigers had vanished from 80 districts.

In Madhya Pradesh, the number of tigers in protected areas is around 250, down from 710 in 2002, according to Y.V. Jhala and Qamar Quereshi, scientists at the wildlife institute.

Environment secretary Prodipto Ghosh attributed the fall to the new counting methods. “It is pointless to compare the new numbers with the last census because the methods are different,” he said.

Experts sniggered at the explanation. “What does it mean? That the previous census was wrong?” asked P.K. Sen, the former director of Project Tiger, the campaign launched to protect the species.

He said it was time conservation strategies were revamped. “The tiger is not the property of the environment ministry.”

Former environment minister Maneka Gandhi saw things getting worse. “Give it five more years and tigers will vanish altogether.”

However, trends from Corbett National Park in Uttarakhand offered some comfort. “Results from Corbett National Park arrived only yesterday. Our cameras have found 112 tigers,” said Jhala.

The number in Ranthambore stands at 32, but many had expected it to be even lower. “Going by the Sariska catastrophe (all 22 tigers reported in the 2002 census vanished), this is good news,” a forest official said.