28% rise in Indian Bison population in Odisha forest

The forest cover in Odisha’s Hirakud Wildlife division has re-established itself as an ideal habitation corridor of Indian Bison, enjoying protection as scheduled-1 species under the Wildlife Protection Act, with their population logging 28% upward graph as per the findings of the latest census of these animals, an official said on Saturday.

The latest census that concluded on 7 January found the overall population at 848, including 235 Juveniles (27% of total population). 848 Gaurs were spotted in as many as 69 herds. The last census of these animals conducted in November 2024 had found the population at 659.

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Herd size in the sanctuary varies from 6 to 25. The age-sex classification could not be ascertained because of difficulty in identifying the seen animals due to dense forest area and presence of tall grasses. But detection probability was around 80% for estimation of total population, this implies 20% of the population could have been missed due to restricted visibility and group movement creating hurdles in detection, said Anshu Pragyan Das, the Divisional Forest Officer.

As many as 73 Census Units covered 353 Sq.km Debrigarh Sanctuary and recorded the presence of 848 Indian Bison.

Increase in population may be due to species specific habitat management in Debrigarh focusing on feeding and other behaviours of Bison.

At Debrigarh, meadows with bamboo brakes have been developed for grazing and browsing of this animal with emphasis on grasslands.

To ascertain the breeding pattern of Bison (the flagship species of Debrigarh), census is being conducted every 6 months from November 2024. It’s not a seasonal phenomenon in this sanctuary unlike few other pockets of India where their breeding is seasonal. Every Range of Sanctuary is maintaining a monthly register of the number of new born bison

Debrigarh is widely regarded as the ‘Land of Indian Bison’ due to good sighting of big herds in the tourism zone as well as in the eco-sensitive zone on edges of Hirakud Wetland. Bison can migrate long distances too, but in Debrigarh they are seen to display seasonal movement of 5 to 15 kilometers per day keeping their territory mostly constant.