Bioacoustics research at Ugalla centers on chimpanzee long calls – pant hoots – and their role in chimpanzee nest site selection and mediating party reunions. Chimpanzees in savanna habitats are known to form small daily parties and aggregate in larger groups at night. Additionally, population density estimates are significantly smaller and home ranges are significantly larger than those of forested communities. Given their fission-fusion social system, how chimpanzees coordinate reunions remains poorly understood.
While much is known about the function of pant hoots, the species specific chimpanzee long call, few researchers have been able to situate this behaviour in a socioecological context given the necessity to observe both caller and listener simultaneously – often a logistic challenge. To overcome this, I deployed Cornell University’s Autonomous Recording Units (ARUs) in 2006 to pilot test this method at Ugalla. A historically successful approach with marine mammals and birds, acoustic localization has not yet been widely used by primatologists.
The 2006 pilot deployment of 3 ARUs successfully recorded (from >2km) and localized (from almost 1km) playback and wild chimpanzee pant hoots and screams from Ugalla, demonstrating the potential for this method. Additionally, numerous species of bird, six species of primate, bushbuck, and puddle frogs were among other species recorded by ARUs, revealing the potential of this method as an instrument to conduct bioacoustic surveys in remote areas that are difficult to reach on foot. Since then, with the help of Bill Sallee of Santee, California, and John Hildebrand and team at the Scripps Institute for Oceanography in La Jolla, I have developed a new, solar-powered system that records continuously and relays sounds in real-time to a central receiver. This system was deployed (2009-2010) at Issa where at one point 20 solar powered acoustic transmission units (SPATUs) were recording in an area of about 24 square kilometers.
This system has since been improved with the help of Paul Robertson of Cambridge University, and is an integral component of the 2011-2012 survey of the Greater Mahale Ecosystem.
