The pitfalls of wildlife camera trapping as a survey tool in Australia

Abstract

Camera trapping is a relatively new addition to the wildlife survey repertoire in Australia. Its rapid adoption has been unparalleled in ecological science, but objective evaluation of camera traps and their application has not kept pace. With the aim of motivating practitioners to think more about selection and deployment of camera trap models in relation to research goals, we reviewed Australian camera trapping studies to determine how camera traps have been used and how their technological constraints may have affected reported results and conclusions. In the 54 camera trapping articles published between 1991 and 2013, mammals (86%) were studied more than birds (10%) and reptiles (3%), with small to medium-sized mammals being most studied. Australian camera trapping studies, like those elsewhere, have changed from more qualitative to more complex quantitative investigations. However, we found that camera trap constraints and limitations were rarely acknowledged, and we identified eight key issues requiring consideration and further research. These are: camera model, camera detection system, camera placement and orientation, triggering and recovery, camera trap settings, temperature differentials, species identification and behavioural responses of the animals to the cameras. In particular, alterations to animal behaviour by camera traps potentially have enormous influence on data quality, reliability and interpretation. The key issues were not considered in most Australian camera trap papers and require further study to better understand the factors that influence the analysis and interpretation of camera trap data and improve experimental design.

Distance and size matters: A comparison of six wildlife camera traps and their usefulness for wild birds

“…This is in line with previous findings on other species, especially in mammals (Anile & Devillard, 2016; Lyra‐Jorge et al., 2008; Tobler et al., 2008; Urlus et al., 2014). …”

“…(2009) compared video and passive vs. active camera systems and reported a higher sensitivity of the passive infrared systems. Urlus, McCutcheon, Gilmore, and McMahon (2014) also showed that different camera models had different rates of positive triggers. Swan, Di Stefano, and Christie (2014) by comparing two different camera models showed that the results would be significantly different depending on the camera model used.…”

“…If the ambient temperature is low, for example, below 10°C, the difference to the animals is large and the cameras have a higher probability to detect the animal. If the ambient temperature is more or less similar to the temperature of the animals, the cameras trigger the animal with lower probability (Welbourne, 2014 reports a required difference of 4–5°C).…”

“…In addition, body mass is considered an important predictor with larger or heavier animals being recorded more frequently (e.g., Anile & Devillard, 2016; Lyra‐Jorge et al., 2008; Tobler, Carrillo‐Percastegui, Leite Pitman, Mares, & Powell, 2008; Urlus et al., 2014). This is based on the fact that the heat signature increases with increasing body size.…”

How do passive infrared triggered camera traps operate and why does it matter? Breaking down common misconceptions

“…Rovero et al 2013) or core temperature (e.g. Meek et al 2015) affecting a PIR trigger is ambiguous at best and technically incorrect at Figure 4C that has six detection windows at the top and two detection windows at the bottom of the lens. Figure 6.…”