Calcutta: The Bengal tiger is looking to Assam to help it survive a massive population erosion in one of its erstwhile strongholds.

The plan is to relocate a male and two females from Kaziranga or Orang in Assam to Buxa Tiger Reserve in north Bengal before 2020. The next batch - again a male and two females - will be released when the first three settle down in their new home in Alipurduar sub-division of Jalpaiguri district.

The tiger relocation project, conceived in 2016, is a collaborative effort involving the forest department, the National Tiger Conservation Authority, the Wildlife Institute of India and the Global Tiger Forum.

The strategy of relocating tigers to repopulate dying reserves had been first tried out at Sariska in Rajasthan in 2008. Panna in Madhya Pradesh benefited from a similar initiative in 2010, followed by some other parks. But all these relocations were intra-state. The first inter-state relocation happened on June 21 this year, when a big cat from Kanha was shifted to Satkosia in Odisha.

The Buxa reserve spans 760sqkm and shares its borders with Assam and Bhutan. Buxa used to have high tiger density because of its abundant prey base. Over the years, the habitat has deteriorated and led to a depletion of the prey base, directly impacting tiger survival.

Trap cameras have not recorded a single tiger anywhere in Buxa over the past three to four years, although scat and remains of prey indicate there are still a couple of them left. "These tigers are possibly restricted to the northern hilly terrains," a forest official said.

The forest department decided on a tiger augmentation plan sometime in 2016. A detailed project report was prepared in consultation with the Wildlife Institute of India and the Global Tiger Forum. "We gave the in-principle approval last year. The plan involves habitat improvement, prey augmentation, protective mechanisms and working with local stakeholders to negate human-tiger conflict," said a member of the National Tiger Conservation Authority.

The primary budget for the project is around Rs 45 crore.

"Since January, more than 200 deer brought from different sanctuaries in the state have been release into the park. We plan to release sambars in the next phase," Subhankar Sengupta, field director of the tiger reserve, told Metro.

Habitat improvement is also being done in the form of creating more grasslands and open areas, Sengupta said.

The overall success of the project hinges on the relocation of some villages inside the park and rehabilitation of the villagers. There are around 40 forest villages in the reserve, around 15 within the core area.

A team from the Wildlife Institute of India is currently stationed at Buxa. Along with forest department officials and frontline staff, they have opened discussions with the villagers to persuade them to shift . Around six settlements have to be relocated in the first phase.

"Shifting will have to be a completely voluntary decision and there will be no forceful eviction. The forest department will pay for the rehabilitation," said Ravi Kant Sinha, the chief wildlife warden of Bengal.

According to Sinha, Assam was looked at as a viable option in the relocation plan because big cats there are demographically, genetically and behaviourally suitable for Buxa.

The tigers will be tracked, tranquillised and radio-collared before being transported to Buxa. The post-release phase will involve constant monitoring of how the tigers adapt to their new environment.