Technique for non-invasive identification of wild frogs using photographs

Abstract

Photographic mark-recapture is a recent mark-recapture method to identify individuals in a species. This method uses photographs and the species natural pattern to identify them. Amphibians are difficult to mark reliably. Currently, visible implant elastomers (VIE) are the most common way to tag amphibians, however they are still unreliable and can cause infection. Pictures of Cope's gray tree frog (Hyla chrysoscelis) were taken in the summers of 2019 and 2020 to be used as an alternative method for identification. The program Wild-ID was used for this project, which produces a match score by comparing the features of photos. We tested four sample sets of photos. These samples tested photos from the same night, photos from different nights, photos from different years, and overall sample size. Overall, Wild-ID produced a high percentage of correct identifications. This means that individuals can be recognized on the same night, across multiple nights and across years.