Third of macaques at country parks sterilised to control population boom
Nearly a third of wild macaques commonly found in country parks in Kowloon have been sterilised in efforts to control their fast growing numbers, the conservation department says.
Their numbers had jumped from 1,400 in 2002 to 2,100, and were expected to increase to 2,600 in five years.
If left unchecked, the population explosion would lead to more intense competition for food in the wild and force some of the weaker members of the tribe out to urban areas, triggering more clashes between humans and monkeys, the department said.
The macaques, which were first recorded in the city in the late 19th century, mostly live inside and on the periphery of the Kam Shan and Lion Rock country parks. Under the contraception programme, the macaques are caught and given an injection that will stop them from breeding for five to 10 years, long enough to cover their most fertile years. They generally start breeding at the age of five, and can live up to 17 years.
Wong Che-lok, fauna conservation officer of the Agriculture, Fisheries and Conservation Department, said the department wanted to cut the growth rate to 3 per cent a year, from up to 7.8 per cent, by sterilising half the macaque population.
'In 10 to 12 years, when many of the sterilised macaques reach the end of their lifespan, we hope to see negative growth,' said Dr Wong, who retires next month after spending 20 years on primate studies.
The programme got off to a bumpy start in 2002, as the monkeys continually eluded capture. Many ways of administering the drug - including mixing the contraceptive with food - were tried in vain.
'They were so smart, they refused to take the food after they smelled something unusual in it,' Dr Wong said.
Officers made a major breakthrough last year, when they successfully lured the monkeys into a giant cage after earning their trust through regular and repeated feeding by the same person. More than 560 macaques were caught last year, adding to a total of 830 caught since 2002.
Once caught, the macaques are anaesthetised and examined on-site by a team of veterinary surgeons hired by the department to implement the programme.
The vets record their height and weight, implant a microchip, photograph them, and administer a rabies vaccine, antibiotics to prevent infections and painkillers.
They also treat any injures found on the monkeys. The macaques are released back into the wild after they regain consciousness.
Gail Cochrane, the veterinary surgeon leading the contraception project, said the injection, which costs about HK$500 each, was safe for the animals and has no side effects, even on pregnant females.
The injection also has no impact on the animals' sex lives and the social status of individual members within the hierarchy of a monkey tribe. 'They will have no idea about the contraception. Since it will not affect their hormone level, their behaviour will be the same,' she said.
Dr Cochrane said that while some macaques got hurt in fights when locked inside the cage, threats to the monkeys also existed in the wild.
The macaques risk getting knocked down by cars and falling into traps for wild boar. They are also threatened by human contact as more macaques are venturing into urban areas.
Last year, Sha Tin residents who live close to the two country parks filed more than 400 complaints about nuisances created by stray monkeys, up from 163 in 2003.
