Patna: Valmiki Tiger Reserve is home to 42 tigers, including 32 adults, which have been photographed during the internal annual census conducted by the reserve management earlier this year.

A year ago, the number of adult tigers was 31, and in 2015-16 Bihar's only sanctuary for India's national animal had 28 adult big cats.

"Our camera trap data show presence of at least 32 adult tigers and 10 cubs in Valmiki. We would, however, release the figures only after getting the data cross-checked by the Wildlife Institute of India (WII), Dehradun," principal chief conservator of forest D.K. Shukla said on Sunday, which happened to be global tiger day -observed on July 29 every year since 2010.

He said that the cross-checking of data at the WII helps in substantiating the figures because the Institute gets such data from across the country and thus it rules out the possibility of duplicity as experts there cross-check it with data from adjoining tiger reserves also. The WII uses a special software - in which stripes of the photographed tigers are matched - for cross-checking. Every tiger has a unique stripe pattern, which also means the national repository data help in identifying the reserve whose tiger is poached or whose skin is found.

According to new norms, all tiger reserves are supposed to carry out the internal census work every year using the camera trap method. At Valmiki, which is located around 290 km northwest of Patna, 300 pairs of cameras were used in the survey.

Attributing the growing number of big cats at Valmiki to better habitat management, Shukla said that one of the key focus areas had been increasing the availability of grasslands inside the reserve as it provided a conducive environment for herbivores - prey base for tigers.

He said that better protection measures too were playing an important role in keeping the activities of poachers under check.