1Anthropology, University of Wisconsin Oshkosh, 2Resource and Environmental Management, Simon Fraser University
Thursday All day, Clinch Concourse
Great apes are difficult to count directly and indirect signs, such as nests, are frequently used to census their populations. However, substantial time and effort are required to provide reliable population density estimates from nest surveys. Camera traps offer a potential alternative and have become a popular tool for assessing mammal populations. Recent camera trap studies of chimpanzee and gorilla populations have produced promising results, but to our knowledge this method has not been used to census populations of another great ape, the orangutan. Here we report on a camera trapping study of Bornean orangutans (Pongo pygmaeus) in the Wehea Forest in East Kalimantan, Indonesia (01°32’46”N, 116°46’43”E). This study was conducted from June 2011-January 2012 and April 2012-present for a total of 12 months to-date. We deployed 13 camera trap stations in 2011 and 42 stations in 2012 over a total survey area of ~50 km2. Camera trap stations consisted of a pair of Bushnell or Reconyx cameras placed 2-3 ft off the ground. During this study we obtained 403 photos of orangutans over 50 independent capture events (photos taken >1 hour apart). At least 9 individuals are represented in these photos with some individuals captured at more than one station. Furthermore, these photos indicate that Bornean orangutans may travel on the ground more than previously thought, even in areas of relatively contiguous forest cover. These results suggest that camera traps, perhaps in combination with other methods, could be a useful tool for surveying and studying orangutan populations.
Support for this research was provided by the Disney Worldwide Conservation Fund, the Trudeau Foundation, Simon Fraser University, and the University of Wisconsin Oshkosh.