Comparing information derived on food habits of a terrestrial carnivore between animal-borne video systems and fecal analyses methods

Abstract

In recent years, animal-borne video cameras have been used to identify the food habits of many species. However, the usefulness and difficulties of identifying food habits from animal-borne video cameras have not been sufficiently discussed in terrestrial mammals, especially large omnivores. The aim of this study is to compare the video analysis of foraging behavior by Asian black bears (Ursus thibetanus) acquired by camera collars with estimates from fecal analysis. We attached GPS collars equipped with video cameras to four adult Asian black bears in the Okutama mountains in central Japan from May to July 2018 and analyzed video clips for foraging behavior. Simultaneously, we collected bear feces in the same area to determine food habits. We found that using video analyses was advantageous to recognize foods, such as leaves or mammals, that were physically crushed or destroyed while bears chewed and digested foods, which are difficult to identify to species using fecal analyses. On the other hand, we found that camera collars are less likely to record food items that are infrequently or quickly ingested. Additionally, food items with a low frequency of occurrence and short foraging time per feeding were less likely to be detected when we increased the time between recorded clips. As one of the first applications of the video analysis method for bears, our study shows that video analysis can be an important method for revealing individual differences in diet. Although video analysis may have limitations for understanding the general foraging behavior of Asian black bears at the present stage, the accuracy of food habit data from camera collars can be improved by using it in combination with established techniques such as microscale behavior analyses.

Temporal and individual variation in the feeding habits of Asiatic black bears (Ursus thibetanus)

“…For instance, different food items vary in digestibility, leading to potential overrepresentation of harder‐to‐digest items like green vegetation and underrepresentation of meets (McLellan & Hovey, 1995 ). To mitigate these biases, future studies should consider complementary methods, such as direct observation (Tezuka et al., 2023 ) and stable isotope analysis. Third, the data on April and late October were sparse due to the difficulty in collecting samples during these periods.…”

What's going to be on the menu with global environmental changes?

“…Telemetry: Tracking individuals can determine habitat use, and diet selection amid environmental change (Blévin et al, 2020), and back-tracking (i.e., retracing the path the animal has travelled) can be used to obtain fecal samples for further diet analysis. Animal-borne cameras may capture images of food being eaten (Tezuka et al, 2023), although considerations should include appropriate sizing of devices (Wild et al, 2022), and the minimization of harm or interference to the subject's behavior (Soulsbury et al, 2020).…”