Supplementation of eastern swamp deer in Manas National Park, Assam, India

Summary

The eastern swamp deer (Rucervus duvauceli ranjitsinhi), Vulnerable and numbering only 300-500 animals concentrated almost entirely in Kaziranga National Park, had dwindled to a small remnant in Assam's Manas National Park, a UNESCO World Heritage Site seeking to restore lost species. The Wildlife Trust of India, with the Assam Forest Department, developed a national translocation protocol at an expert workshop, opting for passive mass capture over chemical immobilization, using a screened, adjustable tarpaulin boma at Mihimukh, where deer were already habituated to elephant-riding visitors. In December 2014, after an elephant-driving approach failed, handlers let about 60 deer move voluntarily into the boma before securing them; 19 deer were captured, sedated only if antlered, and driven 400 km by padded, ventilated trucks to Manas, all surviving the journey and released into a 15-hectare acclimation boma. Five fawns were born in the boma by May 2015, but prolonged confinement caused forage scarcity, refusal of supplementary feed, worsening health and endoparasite buildup, and the death of two females; poor health also ruled out fitting radio-collars before the eventual June 2015 release, after which two males were killed straying from the park and one female was taken by a leopard, with the rest tracked daily on elephant back in small dispersed groups rather than one herd as in Kaziranga. The project rates capture and translocation a clear success given past high-mortality operations elsewhere in India, but monitoring less successful, concluding that collaring animals at the source would have avoided the loss of tracking capability caused by their declining health in the boma.