Hunting disturbs waterbird communities in Tamil Nadu wetlands

As dusk falls upon the wetlands in Kanchipuram district in Tamil Nadu, a diverse array of waterbirds, from storks to ibises to pelicans, congregate by the edge of the water. Some of them do not live to see the dawn. Hunters gather their locally crafted single-barrel, muzzle-loading guns and dauntlessly venture out in groups to capture waterbirds.

There are a few hundred hunters who hunt during the weekends from December to April, during dawn and dusk when the waterbirds are highly active. Each hunter gets about 21 birds on each foray—the bigger the better. Most of them know hunting is illegal, but none of them has ever been caught.

These hunting patterns were revealed in a recent study on illegal waterbird hunting in South Asia. Researchers found that hunting overrides habitat factors, reduces waterbird diversity, density, and pushes the community towards smaller-sized birds. The motive for hunting was not subsistence, but commercial as demand for waterbirds has risen dramatically over the past few years.

The study “exposes illegal hunting to be a serious emerging threat to waterbird conservation and human health as well,” said Ramesh Ramachandran, lead author of the study who was a student with the MSc in Wildlife Biology & Conservation programme, at the National Centre for Biological Sciences, Bengaluru during the study.

Hunting has already threatened bird and mammal populations across tropical forests. In Southeast Asia, overhunting is one of the main causes of drastic declines in wildlife. According to India’s Wildlife Protection Act of 1972, hunting of wild animals and trade in game is prohibited. Yet it continues unabated in the inland water bodies of the east coast of India, but the scale, motivations and impact on waterbird communities was unknown.

Hunting has more influence than habitat

Ramachandran and his team surveyed 27 agricultural wetlands ranging from 0.05 to 0.35 hectares in area, in the district of Kanchipuram in the southern state of Tamil Nadu where half of the population is engaged in agriculture, mainly paddy. These included two protected areas, Vedanthangal and Karikilli, with strict enforcement, for comparison. During February to April 2014, they counted birds and noted the species and sizes of the birds that gathered around the wetlands during dawn and dusk.

After repeated visits and trust built over a period of three months, Ramachandran interviewed 272 active hunters through questionnaire surveys to understand their motivations for hunting, the intensity, and the species targeted. To estimate habitat factors, seven habitat variables were measured, which included area of water-spread and surface vegetation. In addition, the team conducted market surveys in five open markets as well as 681 local roadside eateries to see if they served waterbirds.

Over 8000 birds were counted and a total of 53 species of waterbirds were recorded, out of which 47 were targeted by hunters. The waterbirds included not only resident species, but also migratory species that use the wetlands as habitat during the winter months.

Hunters preyed on large-sized waterbirds, such as black-headed ibis, Asian openbill, great egret, painted stork, and spot-billed pelican. Each season, around 1745 waterbirds were caught per wetland.

“The scale of hunting was both surprising and hugely disconcerting,” said K.S. Gopi Sundar, director of the SarusScape programme of the International Crane Foundation and scientist with the Cranes and Wetlands programme at the Nature Conservation Foundation, Mysore. “This is very serious, and needs to be curtailed if we are to sustain waterbird populations in our region.”

Encouragingly, one of the protected bird sanctuaries, Vedanthangal, remained free from hunting, but five claimed to have hunted in Karikilli, indicating weak law enforcement. Many of the species caught fall under Schedule IV of India’s Wildlife Protection Act, and their hunting is a punishable offence.

Hunting exerted a greater effect than habitat in shaping the community of waterbirds by lowering species richness, the density of fish-eating species, and skewing the community towards smaller bodied species because the larger birds are selectively targeted.

From subsistence to commercial hunting

Over 21,000 birds belonging to 47 taxa (valued at Rs. 8,199,320 or US$127,289) were put up for sale in the open markets. Contrary to expectations, hunting was not for subsistence as is often assumed. Rather, it was a commercial activity driven primarily by market demand, most likely due to changes in food preferences. Over time, the researchers believe, subsistence hunting has transformed into a commercial activity.

“Hunters, in large part, appear to be hunting for extra money,” said Sundar. “They already have other livelihood options, and they hunt illegally because of the ready extra money they can make over the weekends and holidays.”

Hunters earned on an average Rs. 12,600 (US$196) from their hauls—two-thirds more than the average monthly per capita income in India. Ramachandran points out that “this makes hunting really lucrative.”

While almost 75% of the hunters claimed to have to sold the birds to 426 eateries, only eight of the 681 roadside eateries admitted to serving wild waterbirds. Pond heron meat was the most frequently traded species. “This led us to presume that most of the eateries, to reduce costs, substituted wild birds for chicken,” said Ramachandran.

With the huge amounts of wild waterbird meat sold, Ramachandran warns that the possibility of zoonosis—a disease transmitted from animals to humans—is high. He points out that “pinpointing the origin of a possible zoonotic disease outbreak [would be] impossible as the consumers would be unaware that they were actually eating wild birds.”

Conserve across the landscape

Around the world, wetlands have been threatened primarily due to conversion and habitat deterioration, making them unsuitable for waterbirds to use as habitat. But this study demonstrates that even human-managed wetlands can support biodiversity and are refugia for waterbirds.

“This means that attention to waterbird populations only in reserves will be hugely inadequate as a mechanism to conserve them,” said Sundar. He emphasizes that we need to “take wetlands seriously for not just for generating economic benefits but also for being essential to conserve waterbirds.”

Instead of protecting isolated and large natural wetlands, the researchers propose the protection of wetlands stretching across entire landscapes for conservation of waterbirds in the long-term. Sundar also suggests enhanced law enforcement, which involves joint action with the forest department, police, and also village panchayats and farmers. Even though hunting is an ancient practice, making consumers more aware that it is illegal will be important.

The forest department officials responsible for the district say that in response to the recent reports on hunting of waterbirds, they have increased patrolling and have booked hunters in the recent months. They have also been spreading awareness about the ecological consequences of hunting and punishing offenders to deter hunters.

Citation:

• Ramachandran, R., Kumar, A., Gopi Sundar, K.S., & Bhalla, R.S. (2017). Hunting or habitat? Drivers of waterbird abundance and community structure in agricultural wetlands of southern India. Ambio, 46:613-620. doi:10.1007/s13280-017-0907-9