Software glitch in tiger count


KOLKATA: Flooded with more than 300 tiger images from the Sunderbans Tiger Reserve (STR) area, the software being used in the phase IV monitoring has so far been unable to give a minimum count of big cats in the mangroves.

Meanwhile, the WWF-India officials while doing a manual exercise - matching of stripe patterns to identify unique individuals - have predicted the minimum number of tigers in National Park East range of the mangroves, comprising forests of Bagmara, Chamta and Gona, to be around 22.

"More fine-tuning needs to be done before we come to a conclusion. Our officials have left for Wildlife Institute of India ( WII) in Dehradun to procure an updated version of the software - ExtractCompare," said Anurag Danda, the Sunderbans chapter head of WWF-India, which is doing the camera-trap exercise in three ranges of the Sunderbans - National Park East, Sajnekhali and Basirhat - at a project cost of Rs 36 lakh.

According to Danda, after scrutinizing, selecting photos and entering the camera-trap data and their associated photo images into a database with other information like location, date and time, the ExtractCompare software is used for automated matching to find individuals.

"However, the software couldn't handle the rush of images - more than 100 per range. We are now manually drawing the stripe patterns after taking printouts of the images," added Danda.

Moreover, two tigers have so far been photo captured in both the National Park East and Sajnekhali ranges. "So, instead of focusing on a range-specific minimum tiger number, we might give a minimum number for the entire Sunderbans," he added. A forester said taking into account the minimum 20 tigers in South 24-Parganas forest division, the entire mangroves may well have at least 100 big cats.

However, Danda is not ready to relate the rush of images to a possible rise in tigers' number in the Sunderbans at the moment. "More than 100 images don't mean more than 100 individuals. At National Park East, a male tiger was captured in 12 camera trap stations moving over more than 194 square kilometres area in the forests of Bagmara, Chamta and Gona. But the tiger will be counted once. So, we are waiting for the updated version of the software which is expected to give a close match," he said.

According to Danda, the WWF officials have encountered a similar problem in the Nilgiri landscape, where they are doing the phase IV tiger monitoring with the help of trap cameras.

"We could so far undertake the manual identification exercise for the National Park East only, spread over almost 650 square kilometres. As of now, we expect a presence of at least 22 tigers here," he said, adding that the entire exercise will take at least another month to end.

An official said the exercise in South 24-Parganas forest division last year didn't encounter any software problem since the tiger number was comparatively less there.

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