Expensive radio collars with in-built mortality alert, global positioning system (GPS) and very high frequency (VHF) systems used to track the movement of tigers have come under fire from conservationists after the seven-year-old tiger Jai went missing from Umred Karhandla Wildlife Sanctuary near Nagpur in April.
Well known tiger conservationist Valmik Thapar has questioned the usability of collars after scientists of Wildlife Institute of India (WII) lost track of Jai.
“I am worried about Jai. Why was a radio collar fitted on the tiger and why is it not functioning?” Thapar had asked on August 20 and asserted that the Wildlife Institute of India, which radio collared Jai, should be held accountable for defunct collar.
Thapar, who worked extensively on tiger movement and its conservation, said he was against of radio collaring of tigers.
But, scientists at WII have backed up the methodology that has proved instrumental in re-introduction of tigers in Sariska and Panna.
“The collars are used to study tiger movement and not to control them. There have been only half a dozen cases in past where collars didn’t yield the kind of result we expected because of various reasons - fighting, battery drain, damage to collar, tough terrains and others. All in all, the methodology is the best available - Sariska and Panna have already proved it,” VB Mathur, director WII told Hindustan Times.
The collars don’t come cheap. Each collar with both GPS and VHF facility cost nearly Rs 3.50 lakh. Available only with selected merchants, these collars are mostly imported from Germany. There are some collars that come with ‘drop off’ feature that can be easily detached from a growing tiger’s neck through a signal to avoid suffocation. This type of collar is even costlier with price tag of Rs 5 lakh. Scientists avoid these collars unless there’s emergency because it means replacing a collar if it drops off.
GPS provides satellite based movement of tigers (that can spread across several hundred sq km), while movement through VHF can be studied through ground links up to a distance of 2-5 km.
The major drawback with the collars is its battery life. Each of the collars has a battery life of nearly one year because of which scientists cannot track the movement of tigers 24X7. Scientists can remotely switch on or switch off the battery in the collar. A longer duration time limit is thus set (generally from 5-8 hours) when the tiger is inside a protected area and shorter duration (1-3 hours) when it is outside such an area.
Jai was fitted with a German-made GPS vectronic collar. Bilal Habib, a scientist at WII who fitted the collar on Jai, told Hindustan Times that high tension wires and limited space in Umred led to losing track of the animal.
“Umred has high tension power lines that have electromagnetic fields. Similarly, GPS and VHF collars too have the same fields. When both coincide, we fail to get signals. That’s how Jai’s collar showed irregular behaviour,” Habib said. He said that the collar was fitted with mortality alert that hasn’t given any signal till date.
Jai was collared in September 2015. But barely two months later on November 25, scientists realized the GPS had stopped working. But they continued tracking the big cat through VHF signals for the next five months. On April 18, the VHF signals also stopped, prompting an intensive search for the tiger.
Habib said Jai had extended his territory from 380 sq km when he was collared, to 580 sq km when the last VHF?signals were recorded. Umred is spread across only 189 sq km area. There are 13 tigers in Umred of which 7 are male including Jai.