The sanctuary was established in 1987 and census began in 2010, where more than 70 animals were recorded and their number has been steadily rising. In the previous census in December 2013, the number was above 124.

This year, 120 volunteers, mostly college students, participated in the census. They were separated into five teams and at the end, data from all five teams were collected and compiled.

The officials claimed that the numbers had definitely risen by at least 20 per cent, though the exact figure would be released only by the Wildlife Institute of India by compiling the data from across the country.

Nellai Nayagam, Forest Ranger of Srivaikuntam Division, who was in-charge of the exercise, claimed that by seeing the data, they can sense a 20 percent increase in numbers. Apart from blackbucks, they have also collected data of spotted deer, sambar deer, fox, jackal and so on claimed Nayagam. When asked about the reason for the increase in numbers, he claimed that the conservation measures adopted by the Forest Department was the prime reason. The first measure taken was to demarcate the boundary and lay fence around the sanctuary to protect the species from external contact, claimed Nayagam.

The antelope were able to move about freely in a secured environment. Another important reason is the appointment of six anti-poaching guards who guarded the sanctuary round the clock, he said. Nayagam further added that another reason was the creation of suitable environment for the animals. Before his arrival, there were only three water tanks for deers, but now there are 18 large tanks.

They have also dug 2,500 small water bodies that is recharged during rains, which increases the water table. Developing grass lands are other features of suitable environment whereby the blackbucks would have sufficient food inside the sanctuary. They have also taken measures to stop forest fire by coordinating with the locals and are working tirelessly to increase the numbers, he added.