Journal Article

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

Randler, Christoph, Kalb, Nadine

2018

Overview

Camera traps are increasingly used in ecological research. However, tests of their performance are scarce. It is already known from previous work that camera traps frequently fail to capture visits by animals. This can lead to a misinterpretation of ecological results such as density estimates or predation events. While previous work is mainly based on mammals, for birds, no data about if and how camera traps can be successfully used to estimate species diversity or density are available. Hence, the goal of our study was an empirical validation of six different camera traps in the field. We observed a total number of N = 4567 events (independent visits of a bird) in 100 different sessions from March 2017 until January 2018 while camera traps were deployed. In addition, N = 641 events are based on a comparison of the two close‐up camera traps especially designed for birds. These events were all directly observed by the authors. Thus, the cameras can be compared against the human observer. To give an overall assessment and a more generalizable result, we combined the data from the six camera traps and showed that bird size category (effect size = 0.207) and distance (effect size = 0.132) are the most important predictors for a successful trigger. Also, temperature had a small effect, and flock size had an impact with larger flocks being captured more often. The approach of the bird, whether it approached the camera frontally or laterally had no influence. In Table , we give some recommendations, based on our results, at which distances camera traps should be placed to get a 25%, 50%, and 75% capture rate for a given bird size. The goal of our study was an empirical validation of six different wildlife trail cameras in the field. We conducted a series of standardized tests to assess, if and under which conditions wildlife trail cameras can be used for bird research. In the field, we observed a total number of N = 4567 events. In addition, N = 641 observations are based on a comparison of the two close‐up cameras especially designed for birds. To give an overall assessment and a more generalizable result, we combined the data from the six cameras and showed that size and distance are the most important predictors for a successful capturing. Also, temperature had a weak effect, and flock size had an impact with larger flocks being captured more often. The approach of the bird, whether it approached the camera frontally or laterally had no influence.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc
• Subject: Biodiversity / bird research / Birds / camera or photo traps / Cameras / Density / Ecological effects / Ecological research / Group size / methods check / Original Research / passive infrared sensor / Predation / Species diversity / Traps / Wildlife / wildlife trail cameras