Patna, Nov. 15: Valmiki Tiger Reserve officials would begin the annual tiger census work at the sanctuary from the first week of December.

This would be the second such census conducted at the reserve.

A total of 200 pairs of camera traps would be installed over an area of 899sqkm in the reserve, around 289km north of Patna, for collection of data for the census.

The World Wildlife Fund, India, would provide the VTR officials technical assistance. The work would be carried out simultaneously with Chitwan National Park in Nepal.

Santosh Tiwari, the VTR conservator-cum-field director, told The Telegraph: “According to directives from the National Tiger Conservation Authority (NTCA), we have started preparations for the annual census. While we are awaiting funds for 75 camera traps from the NTCA, a proposal has been sent to the state environment and forests department for funds for another 125 cameras. We expect the groundwork to be complete by the end of this month so that the monitoring work can start from the first week of December.”

The National Tiger Conservation Authority, in 2011, mandated the country’s tiger reserves to conduct the census work annually on their own.

According to the census conducted with camera traps in 2010, eight tigers were spotted over 440sqkm of VTR’s core area. The count rose to 22 during the 2013 annual tiger census, the first one conducted by the state’s tiger reserve.

Explaining the camera-trap method, VTR field director Tiwari said: “The new camera traps use advanced technologies, including digital cameras, infrared rays and sensors. Once the sensors detect the movement of a tiger, the camera automatically captures photographs with the infrared rays. Duplication (of tiger count) under this method is ruled out, as every tiger has unique stripes.”

The upcoming census at Bihar’s only tiger sanctuary would be done over a period of 45 nights.

In the Terai region of the Himalayas, the tiger reserve has the Chitwan National Park and Parsa Wildlife Sanctuary (Nepal) in its north and Uttar Pradesh to its west.

Tiwari added: “Each pair of camera trap would monitor an area of 1sqkm around it. If the monitoring work starts as planned in the first week of December and continues for 45 days, we expect the work to be completed around mid-January. Once done, the census report would be sent to the Wildlife Institute of India, Dehradun.”

Till 2006, tiger census in the country used to be conducted through the monitoring of pugmarks.

Sources said the NTCA, after consultation with the other tiger reserves in the country, introduced the system of annual census by tiger reserves in November 2011. It was introduced to ensure better estimates of the number of tigers on a regular basis.