India's tiger population is set to record a rise as nearly 1,700 big cats have been captured on camera traps across 46 of the country's 50 reserves in the latest annual estimation. After pugmarks and scat samples are analysed and figures of manual monitoring are also in, the overall number is likely to cross the current tiger population figure of 2,226 officials told DNA.

The heartening development comes against the backdrop of global reduction in tiger population. Not to forget, 122 tigers died across India in 2016— the highest in the past five years.

No camera-trap data has come in from Dudhwa, Indravati, Bor and Rajaji reserves, and officials are also analysing the photographs to know the number of adults and cubs, sources in the National Tiger Conservation Authority (NTCA) said.

A comprehensive tiger population estimation — across three phases — is done once in four years. This is combined with the annual process called the Phase-IV. The next countrywide population estimation is set to begin in a month and will end in December 2018. Officials are enthused by the numbers because the previous Phase-IV estimation was incomplete and did not include data from more than 10 tiger reserves.

India had registered a rise of 30 per cent in its tiger population with the estimated numbers across reserves going up to 2,226 in 2014 from 1,706 in 2010. The increase made us home to 70 per cent of the world's tiger population.

"The camera-trapping method helps prevent duplication and we are able to establish a minimum number of individual tigers. From the data that has come in from all tiger reserves, the overall picture looks positive. We are hopeful that the 2018 population estimation would reinforce and reconfirm these positive results," said an NTCA official.

The quadrennial tiger population estimation uses a double-sampling method. This combines field surveys where tiger pugmarks, scat and DNA are collected and analysed. The individual tiger numbers from photos and data from ground surveys are used to extrapolate and arrive at a final tiger population estimate. This way, maximum possible forest areas are covered and it also prevents duplication.

Experts and officials said that tiger population has increased at a rate of six per cent per annum.

A total of 3.78 lakh sqkm of forest area had been surveyed across 18 tiger-bearing states for the 2014 estimation and the highest number of tigers — 406 — had been found in Karnataka.