RESULTS
Twenty-four out of the 30 concrete shelters and 19 out of the 30 wooden shelters were occupied at least once by A. robusta during the field test period. Cameras were placed in 11 shelters, each of which had a different A. robusta individuals. The film quality was generally excellent, including good lighting (Fig. 5), and a total of 850 hours of video footage with an A. robusta in view was generated. Eight individuals stayed longer than 5 days in a chamber that was being filmed, while three stayed over 30 days. This suggests that the camera was accepted by the frogs, and not a source of disturbance. In addition to frogs, various other species sought refuge under the artificial shelters and were captured in the video footage. These included other small vertebrates (skink species) and invertebrates such as ants, earthworms, velvet worms, cockroaches, and millipedes.
Although the cameras were thoroughly tested before being deployed in the field, a few issues arose during field testing. In two camera setups, the dates and times displayed on the video files were inaccurate after batteries were replaced. To resolve this issue, we reran the codes for the clock, which successfully fixed the problem for one camera. However, we had to replace the clock module in the other camera. In one camera setup, the brightness of the Infrared LED light decreased in some videos before eventually turning off. This occurred towards the end of the expected video duration and was likely due to the lower voltage available. The issue was resolved by changing the battery and always using fully charged batteries. The final issue was that despite adjusting and testing each camera’s focus before deployment, some cameras produced out-of-focus video. This was primarily attributed to the camera sliding down too deep (and hence out-of-focus) in the shelter setup. This was sometimes due to the camera hole in the artificial shelters being slightly wider than the camera PVC pipe, causing the camera to slide down too far. In other cases, it appeared that the camera had been moved during filming, probably due to disturbance from wildlife such as brush turkeys or feral pigs. To address these issues, we applied multiple layers of Duct tape around the camera PVC pipe to secure it in place and prevent any sliding or moving. Another common cause of unfocused videos was the gradual elevation of the soil beneath the camera due to the burrowing behaviour of earthworms, but this could not be prevented.
We initially envisaged that the camera setup could be damaged by moisture. They were sitting in a wet rainforest environment with regular heavy rain, and the 62 battery and USB drive changes were all performed in >90% humidity and sometimes during rain. However, no water damage was observed on the cameras, batteries, or USB storage drives. This was even the case for one of the cameras which spent time with its lens end underwater when one of the chambers was flooded during heavy rain. The camera kept recording and was not damaged.