Equipment and Techniques for Nocturnal Wildlife Studies

摘要

Many biologists speculate on the nocturnal behavior of wildlife. Night-vision technologies may provide ways to move beyond speculation to observation of nocturnal activity. Nocturnal activity data collection is often secondary to broader study objectives; consequently, techniques for such studies are poorly understood and infrequently used. We reviewed 53 papers to examine image enhancement (i.e., night vision) and assess trends in nocturnal research techniques. We also conducted a field study on nocturnal behavior of roosting cranes (Grus spp.) to evaluate equipment function and efficacy for wildlife studies. A third-generation night-vision scope greatly outperformed a pair of first-generation night-vision binoculars, and we were able to identify cranes by species and observe and record their behaviors while they were on their nocturnal roost sites. Techniques reported in the literature included use of moonlight or natural ambient light, spotlight or simulated luminosity, remote photography, surveillance radar, infrared thermal imaging, and image enhancement. With the many techniques available, scientists can select the procedure or a combination of strategies explicit to their purpose. We believe night-viewing technologies are an exceptional, nonintrusive, functional tool for wildlife ecology studies. However, even the best equipment will have problems or issues with contrast, inclement weather, and large group size and density. Regardless of the specific method used and the inherent challenges, we believe third-generation, American-manufactured night-vision equipment can provide valuable insight into the complete life history of animals and can promote a more comprehensive approach to wildlife studies.