The tiger population in the country has risen to 1706 compared to 1411 in 2006 -- a 12 per cent increase that excludes the big cats of Sundarbans, the latest Tiger Census said today, thanks to sustained conservation efforts.

Environment minister Jairam Ramesh, who released the All India Tiger Estimation Exercise for 2010, said that "the mid-point range" of tigers in the country is 1706.

"The previous census in 2006 did not cover Sundarbans. ...That is why I am comparing 2006 and 2010.... When you compare the like with the like, 1411 in 2006 increases to 1636 in 2010. But if you include 70 estimated population in Sundarban, the total estimated population--there is a lower limit and there is an upper limit--the mid-point range is 1706 tigers," the minister said.

Ramesh said when the Sundarban figure is excluded, the total estimated tiger population figure stands at 1636.

"This figure at 1636 is a 12 per cent increase of 1411 and is welcome news," Ramesh said.

Admitting that there have been higher than normal tiger mortality figures in 2009 and 2010, he said, "But we don't report tiger fertility.

"Tiger mortality is headlines. But when it comes to tiger fertility nobody bothers about it. And remember, this camera trap method has captured 615 photographs of tigers which are more than one-and-a-half years old," Ramesh said.

He said tiger occupancy has fallen in tiger reserves in central India especially in northern Andhra Pradesh and in part of Madhya Pradesh corridor.

"The most positive news has been reported from Maoist-affected Nagarjuna Sagar Tiger Reserve in Andhra Pradesh. We have estimated the number of tigers there to be 60," the Minister said.

He also said there is positive news from other Maoist affected reserves including Indravati (Chattisgarh), Simlipal (Orissa), Valmiki (Bihar), Palamau (Jharkhand).

The census, which was the most comprehensive and scientifically conducted exercise so far, used cameras installed at strategic points like water bodies in forests, as also in respective territories of big cats.

Computers were used to analyse and collate the data.

The 2006 census had shown a sharp fall in the number of tigers in protected areas - reserves, national parks and wildlife sanctuaries - in 19 states across the country.