Individual identification via remote video verified by DNA analysis: a case study of the American black bear

Abstract

Context Researchers and managers often use DNA analysis and remote photography to identify cryptic animals and estimate abundance. Remote video cameras are used less often but offer an increased ability to distinguish similar-looking individuals as well as to observe behavioural patterns that cannot be adequately captured with still photography. However, the use of this approach in species with minimally distinguishing marks has not been tested. Aims To determine the utility and accuracy of distinguishing characteristics of American black bears, Ursus americanus, observed on remote video for identifying individuals in an open population. Methods We compared individuals identified on video with individuals and their sex identified by DNA analysis of hairs collected from hair traps visited by the bears. Key results We found that remote video could be used to determine the number of male and female black bears sampled by the video cameras. Specifically, we matched 13 individual bear genotypes with 13 video identifications, one genotype for each individual. We correctly matched ~82% of video identifications with all 38 genotypes collected from hair traps. Conclusions We demonstrated that distinguishing characteristics of a cryptic animal in remote video can be used to accurately identify individuals. Remote video complements genetic analysis by providing information about habitat use and behaviour. Implications When remote video cameras can be used to identify individuals, a wealth of other information will subsequently be obtained. Multi-year video-based studies can show sex ratios, and relative physical condition; shed light on fine-scale habitat use, such as when and where animals feed and what they eat; and display social interactions and rare behaviours.

Age‐specific, population‐level pedigree of wild black bears provides insights into reproduction, paternity, and maternal effects on offspring apparent survival

“…We installed 12 rub posts, which were ~2‐meter‐high railroad ties wrapped with barbed wire. We constructed hair corrals using one strand of barbed wire (Ramsey et al, 2019 ; Sawaya et al, 2012 ) and placed corrals in locations that bears frequented. We distributed the hair collection systems over 3840 ha to maximize the number of individuals sampled.…”

“…Using methods described by Ramsey et al ( 2019 ), we used genetic‐based individual identifications to inform video capture‐based individual identifications. Generally, we separated videos of black bears from videos of other wildlife and chronologically sorted videos.…”

“…Also, most bears shed their winter coats in unique patterns. For example, some bears lost fur around their sides first, while others lost fur around their rumps first (for extended visual examples of bear traits, see Ramsey et al, 2019 ).…”

“…Therefore, we estimated the individual identification accuracy rate using only video data. To do this, we compared identifications of individuals based on only video data with genetic‐based identifications using bear hair concurrently collected at hair stations equipped with video cameras (Ramsey et al, 2019 ; Reynolds‐Hogland et al, 2022 ). Our identification accuracy assessment was a blind test because we first identified bears via video before genetic data were analyzed (i.e., the original video‐based identifications were uninformed by genetic data).…”

“…Therefore, we estimated the individual identification accuracy rate using only video data. To do this, we compared identifications of individuals based on only video data with genetic-based identifications using bear hair concurrently collected at hair stations equipped with video cameras (Ramsey et al, 2019;Reynolds-Hogland et al, 2022). Our…”