WNPS urges caution over monkey numbers

Tuesday, 17 June 2025 03:39 - - {{hitsCtrl.values.hits}}

The Wildlife and Nature Protection Society (WNPS) has urged caution over monkey population numbers reported by the Agriculture Ministry last week.

WNPS in a statement said it supports the use of data-driven decision-making to mitigate human-wildlife conflict. When carefully designed and implemented, Rapid Visual Censuses (RVC) can serve as a cost-effective starting point to highlight areas of concern. WNPS has been advocating the need for spatial occurrence data of species for years to ensure correct scientific management.

That said, WNPS encourages caution in interpreting the findings of the recent RVC due to several methodological limitations commonly associated with broad-based citizen surveys:

Training requirements: Wildlife population surveys typically require some level of training in species identification and data collection methods to ensure consistency and accuracy. Sri Lanka’s Toque Macaque and Grey Langur belong to several sub species. Therefore, numbers not reflecting those vital data can be misleading
Survey conditions: The brief time frame, broad participant base, and open reporting format can increase the risk of misidentification, double-counting, and data entry errors.

The results reported — including 6.5 million monkeys (5.17 million Toque Macaques and 1.4 million langurs), 2.66 million giant squirrels, and 4.74 million peafowl itself showcase the issues of methodology vigour. For example, this would imply nearly one monkey for every three people in Sri Lanka — a figure that, without independent verification, raises questions regarding ecological plausibility.

WNPS welcomes the initiative to better understand the dynamics of human-wildlife interaction and appreciates the effort to involve local communities. However, we recommend that future efforts to estimate wildlife populations, especially where such data could influence management or policy decisions, be carried out using standardised scientific methods and statistical frameworks.

“We remain committed to supporting national agencies and partners in developing robust, evidence-based approaches to wildlife management — and encourage greater collaboration to ensure data integrity, transparency, and conservation impact,” WNPS said.

On 15 March, the Department of Agriculture conducted a Rapid Visual Census (RVC) across Sri Lanka to assess the presence of commonly reported wildlife species considered agricultural pests. The five-minute observation window, from 8:00 a.m. to 8:05 a.m. invited participation from the general public, including farmers, school children, and local officials. Forms were distributed in advance and collected following the survey.

The species included in the survey were: Sri Lanka Toque Macaque, ‘Leaf Monkeys’, Grey Langur, Giant Squirrel, and Indian Peafowl. The survey did not cover elephants, other wild animal species, or nocturnal crop-raiders, and is therefore not a comprehensive wildlife census.

According to agriculture ministry officials, this was the first Government-led attempt to estimate populations of species considered agricultural pests. The stated purpose was to help identify conflict hotspots, and it was acknowledged that estimates may not be precise due to the limitations of a rapid, publicly conducted count.