Wild boar culling method decided
Animals to be rounded up, sedated then euthanized through injections
By Grace Chua and David Ee
The National Parks Board (NParks) has decided on a method to control the wild boar numbers in Lower Peirce.
It told The Straits Times that it will round them up before vets sedate them with dart guns and euthanise them with drug injections.
But it did not say when the culling will begin or how many animals will be involved.
The wild boar population in Lower Peirce has been getting out of hand, said NParks, as the animals root around for worms and insects, snap off saplings for use as nest materials and pose a safety hazard when they cross roads.
They have been in the spotlight this year – in June, two animals attacked a security guard and a boy.
There are at least two herds of about 40 animals each in Lower Peirce, a population that NParks said is unsustainable.
Its decision to cull them, first publicised in June, has upset conservationists and animal welfare groups that are calling for relocation or sterilization instead.
They said there is not enough data to show that the boars are causing long-term damage to the forest.
NParks conservation division director Wong Tuan Wah said that while studies of long-term forest damage have not been done here, wild pigs have been shown to slow forest regrowth in other countries. By the time data is collected here, he pointed out, the unchecked population might be too much for local forests.
Nature Society Singapore (NSS) president Shawn Lum agreed, citing research by ecologist Kalan Ickes of Clemson University in the United States. The latter’s work on wild pigs in Malaysia’s Pasoh forest reserve shows wild pigs’ nesting habits were responsible for 29 per cent of young saplings deaths and that the pigs specifically targeted the economically and ecologically important family of hardwood trees called dipterocarps.
The NSS is doing surveys to find out whether boar activity is linked to the availability of food sources such as oil palm and sea apple. The surveys will go on until at least next month.
If the link is confirmed, the answer is to clear out exotic species like oil palm, said Mr Tony O’Dempsey, chair of the NSS’ vertebrate study group.
In fact, this is what NParks wants. It aims to reforest Lower Peirce with dipterocarps and other native species, Mr Wong said. But as long as wild pigs are rooting up turf there, the native trees will not stand a chance.
In the most recent draft of the NSS position paper on wild pigs, it said that, even as the number in Lower Pierce needs to be “substantially reduced immediately”, long-term action must be taken to stop the number from increasing.
It recommends studying wild pig populations in the central catchment nature reserve to work out optimal population density for its secondary forest
In the early and mid-1990s, NParks surveys did not record any wild boar in mainland forests but it has made a comeback in the last decade. Over-population put in on the NParks radar two years ago and, for the last year, two conservation officers have kept watch on the Lower Peirce herds. One has been chased up a tree for his pains.
So why have the numbers grown? The boars may have swum over, driven out of neighbouring Johor’s wild areas by development projects.
Over here, they lack predators like tigers, have rich sources of food such as oil palm and are seldom hunted or poached, said Mr Ong Say Lin, who studied the animal last year as a student at the National University of Singapore.
The boars often travel in herds of up to 40 and have been sighted in Upper Bukit Timah, Pulau Ubin and Lim Chu Kang.
Most opponents of culling believe the animal is not aggressive but it can be unpredictable if humans wander into its area.
“A better understanding of these animals and interpretation of their behaviour would reduce any hysteria or sensationalisation,” Mr Ong said.
Tales of boar hunts and sightings
Until the new millennium, when sightings began to increase, wild boars were thought to have been extinct on mainland Singapore since the mid-20th century. But on Pulau Ubin, residents narrate tales of encounters with boars from the 1940s that continue until today.
Mr Chew Yok Choon, 67, a lifelong Ubin resident who was born in 1945, remembers that when he was a child, his family was one of the few that did not own a rifle. Hunting was the order of the day.
“In those days, residents on Pulau Ubin all had rifles. They would hunt flying lemurs, wild boars, civets – all the be eaten,” he said in Mandarin.
Villagers would encounter only a handful of wild boars each year, he said, so the animal became a prized catch.
“There weren’t many boars then. There were a few thousand people living on Pulau Ubin during that time.”
But the equation has changed since then, as the human population dwindled. By 2002, there were only about 100 islanders. Today, Mr Chew estimates that only 30 to 40 residents remain, while the boars have reclaimed the forest and flourished.
The clampdown by the authorities on poaching there about a decade ago was another key factor in the increase of the boars, he said. Mr Chew estimates that 500-600 of the animals now roam Pulau Ubin, a figure based on resident sightings and his own local insight. Other residents say the figure could be higher.
Mr Chew, still sprightly, raised a boar in the mid-1990s, and , based on that experience, has seen first-hand just how intelligent the animals can be.
He said the boar would track him down each time he ventured a few kilometers from home: “Wild boars are clever creatures, maybe even more clever than dogs.”
He and his friends have regularly seen wild boars swimming in the sea between Pulau Ubin and Johor.
But it is the voracious eating habits of boars that Ubin residents speak of with awe.
“They eat anything, even snakes. They will pull down entire banana trees for the fruit, and rip open coconut shells to eat the flesh,” said Mr Chew.
Even durians and, incredibly, dogs as well, appear to be at risk, according to another 58-year-old resident, who preferred not to be named.
“Would you believe that boars eat dogs? It’s true,” he said. “People I know have already witnessed it twice. The boars surrounded the dog, attacked it and ate it. My uncle had to climb up a tree to escape.”
Cull only as last resort, say animal welfare groups
Culling should be a last resort, and used with other management methods, say animal welfare and conservation groups.
Mr Ong Say Lin, who studied the wild boar as an undergraduate, said culling must not be the only method or long-term solution.
Calling for sterilization to be explored, Mr Ong, who heads the Animal Concerns Research and Education Society’s (Acres) office in Laos, said in his personal capacity: “The amount of effort and time put into darting a herd of wild pigs and euthanising them is about the same as darting and sterilizing them.”
He suggests sterilisation methods such as darting pigs from afar and using chemical-laced bait.
To reduce human-animal conflict in residential areas, he proposed using physical barriers and scent deterrents and removing food sources.
Ms Corinne Fong, executive director of the Society for the Prevention of Cruelty to Animals (SPCA), said it supports sterilisation rather than culling.
But a spokesman for NParks said it has ruled out sterilisation as no single-dose chemical contraceptive injection is commercially available. Available drugs need follow-up injections – not practical for free-ranging animals.
Surgical sterilisation, on the other hand, is an elaborate and costly process that requires capture and sedation of the animal, setting up of mobile clinics and holding it in post-surgical care.
These procedures can also cause stress to the animal.
This is why culling may have to be a repeat affair, said the NParks spokesman.
Some members of the public said culling should be put on hold until there is enough data.
Educational psychologist Vilma D’Rozario wants more studies done on the numbers of wild boar in Lower Peirce and elsewhere, and proof that they are causing damage to the forest. If such studies are done and the numbers are found to be too high, “then, yes, I would support management of the numbers but culling would be a last resort”.
She also called for observers from SPCA and Acres to be allowed to watch the culling to ensure it is done humanely.
Formation National Institute of Education professor Diong Cheong Hoong, who has studied the animal, suggests a culling method using large box traps or corrals.
“You might catch non-targeted species like civet cats, deer and monitor lizards, but you just release them and it’s good information to have on other speices,” he said.
“Trapping is a human method as it requires fewer handlers. The fewer the people, the better it is. Rather than chasing them around, do it quickly.”