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

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 8 we give some
recommendations, based on our results, at which distances camera traps
should be placed to get a 25%/50% and 70% capture rate for a given bird
size.