Although the imagers were in agreement with respect to average entrance count over the survey, it is clear from Fig. 3 that there is a degree of disagreement in terms of presence or absence of entrances detected. Output from the contingency tables (Table 5) show that the visual and Vayu had agreement on presence or absence of entrances on 83% of warrens, noting that the Vayu detected entrances where the visual had not on 27% of warrens (Table 6). The Zenmuse was in poor agreement with the visual (27%) and Vayu (34%) and it seems the Zenmuse was particularly prone to detecting warrens that were “false positives” when compared to visual (85%) and Vayu (100%) (Table 6).

Table 5: Contingency tables for the three pairings of methods (visual vs Vayu, visual vs Zenmuse and Vayu vs Zenmuse) using classification of entrance counts as equal to or greater than zero.