50 years of Project Tiger: How are tigers counted in the wild
In Short
- Tigers form the top predators in the ecosystem
- Their role in the balancing act of nature is critical
- India launched Project Tiger in 1973
Today on 9th April 2023, we had a fresh count of the number of tigers present in India right now. Prime Minister Narendra Modi released the latest figures of India’s big cat population as the country celebrates 50 years of Project Tiger on April 9. The tiger population in India has been rising since the launch of the half-a-century-long conservation campaign across the country.Today the Population figure of Tiger has reached to 3167 .
Tigers form the top predators in the ecosystem and their role in the balancing act of nature is critical. India launched Project Tiger in 1973 to begin a concerted effort toward saving the big cat, which had been facing extinction at the time. Over the last 50 years, their numbers have gone up thanks to concentrated efforts under the campaign. According to the 2018 tiger population survey — the last such carried out — India had 2,461 individual tigers.
SCIENCE OF COUNTING TIGERS
Counting tiger numbers is not an easy process and when it all began in 1973, forest staff would use glass and butter paper to track tiger pugmarks. Every tiger has a unique and individual footprint — like human fingerprints — that helps in tracking. Rangers would trace the joint marks off the foot and trace it on butter paper to draw and record the footprint with the idea of using it to track that particular tiger in the future.
However, it’s not that simple. The fact that the pugmarks differ when a tiger is standing, resting, or running adds discrepancies to the process.
CAPTURE MARK RECAPTURE
Over the years the practice evolved into a statistical method of counting. Forest staff turned to the capture-mark-and-recapture method, which is largely used to estimate the population based on a sample.
According to Northern Arizona University, the basic idea is to capture a small number of tigers, place a harmless mark on them, and release them back into the population. “At a later date, you catch another small group and record how many have a mark. In a small population, you are more likely to recapture marked individuals, whereas, in a large population, you are less likely. This can be expressed mathematically.”
Tiger reserves and national parks use the camera trap method to estimate the tiger population by photographing the tigers across the length and breadth of the parks. Camera trapping methodology involves photographing individual tigers who uniquely identifiable by their stripe patterns — just like pugmarks, tigers have unique stripe marks on their body that help in identifying individuals.
Watch how tigers in India are tracked|
Data on individual tiger photo-captures is used in combination with data on prey, habitat, and anthropogenic factors to arrive at tiger population estimates for each landscape.
According to the National Tiger Conservation Authority, the camera traps are set up in areas known to be frequented by the big cat such as animal trails, nullahs, riverbeds, and car tracks. The cameras are placed at knee height concealed from the general view of the animal camouflage to blend in the environment. The camera traps are set in pairs to capture both sides of the tiger.
ASSESSMENT COMPLETE
India is divided into five zones for the survey – Gangetic Plains, Central India and Eastern Ghats, Western Ghats, North Eastern Hills and Brahmaputra Flood Plains, and Sundarbans. During the 2018 assessment, a total area of 381,400 square km was surveyed with 26,838 camera trap locations in 141 sites.
“The tiger numbers are significantly higher than what the reports indicate since camera traps are only set up in the protected areas. With the increasing numbers of the big cat, they do venture out beyond the limits of national parks where we don’t have camera traps,” wildlife conservationist Latika Nath told IndiaToday.in.
With the latest assessment complete, Prime Minister Narendra Modi HAS released the new tiger census data at a mega event to mark the completion of 50 years of Project Tiger in Karnataka’s Mysuru on April 9.
From dense jungles to the Himalayas, tigers are an elusive species—hard to find and hard to count. But, thanks to the use of camera traps, the movements, and behaviors of tigers are now less of a mystery.
Tracking tigers through camera traps has fast become the standard method for countries to count their tigers, and India is currently using this important tool. India is home to over 60% of the world’s tiger population which makes its counting efforts the world’s largest camera-trapping exercise.
How are camera traps used to count tigers?
Camera trapping has evolved from earlier methods of counting tigers by using their footprints—or pugmarks—which provided inaccurate population estimates.
Before setting the camera traps, teams survey an area for the presence of tigers and other wildlife. This helps them to identify promising locations to set up camera traps.
Teams then head out to these pre-identified locations that are often remote and difficult to access. The cameras are loaded with a memory card and batteries and then attached to a tree or post where they will be left for two to three months before being retrieved. They have an infrared beam and will start recording photos and/or video when a tiger—or other wildlife—passes in front of it, breaking the beam.
After the team retrieves the memory cards, they analyze the data. It’s not uncommon to get thousands of photos and videos to sift through!
The cameras are set up in pairs to capture both sides of the tiger to see all of its stripes. A tiger’s stripe pattern is like a human fingerprint—unique to the individual. This helps experts to identify and count the tigers in an area and ensure they aren’t counting the same tiger twice.
Why is India counting its tigers?
Estimating an area’s tiger population informs the conservation measures WWF-India takes in partnership with local communities and the State Forest Department. The Indian government conducts the All-India Tiger Estimation every four years to determine the number of tigers roaming its forests. These surveys are critical for tracking tiger population trends, documenting encouraging stories of success, and highlighting areas of concern where populations are declining.
Two thousand twenty-two is the Year of the Tiger and the 12-year anniversary of the first Global Tiger Summit in 2010 during which tiger range governments made an ambitious goal to double the number of tigers in the wild. In September of this year, Russia will host the second Global Tiger Summit at which a new tiger population estimate will be released.
India, like all other tiger range countries, is counting its tigers to provide an updated population estimate, which will be released by the Summit in Russia this year.
