Comparing the effectiveness of camera trapping to traditional methods for biodiversity surveys of forest birds

Abstract

To compare the effectiveness of camera trapping to more common mist netting, fixed-distance line transect, and fixed-radius point count methods of forest birds, we surveyed bird species diversity at Nanling National Nature Reserve and Chebaling National Nature Reserve, Guangdong, China from 2011 to 2016. At Nanling, 222 bird species were recorded by fixed-distance line transect and fixed-radius point count methods, 43 bird species were captured by mist netting and 47 bird species were trapped by cameras. One species was captured only by mist netting, six species only by camera-trapping, and 164 species only by fixed-distance line transect and fixed-radius point count methods. At Chebaling, 109 bird species were recorded by fixed-distance line transect and fixed-radius point count methods, 42 by mist nets and 27 by cameras. Nine species were recorded only by mist netting, three only by camera-trapping, and 97 only by fixed-distance line transect and fixed-radius point count methods. At both sites, the number of birds captured by mist netting was negatively correlated with increasing body size, whether measured as body weight, body length, wing length, or tarsus length. By contrast, the number of birds photographed by camera traps was positively correlated with the same measures of body size. These results show that bird surveys using different methods may yield different results and that method should be selected to suit the body size of the target bird species. In surveying bird diversity of a wide range of body sizes, mist netting and camera trapping together would be complimentary methods. Our results suggest that a combination of research methods may be necessary to obtain reliable avian diversity estimates.