For the camera: In a wild range of forages, what do you choose to eat, my deer?

• Main Author: Eriksson, Monica
• Format: Text
• Language: Swedish; English
• Published: 2023
• Subjects: Norway; Alces alces
• Online Access: https://stud.epsilon.slu.se/18699/1/ericson.m.20230315.pdf

Animal-borne video collars are a developing technology with increasing picture quality and battery length. This study has investigated its use when studying foraging behaviours of the two largest deer species on the Scandinavian peninsula: moose (Alces alces) and red deer (Cervus elaphus). In the first of two studies included in this thesis, I compared the foraging choice of moose and red deer on both the inter- and intraspecific level. The data were collected from short, spread-out recordings (20 seconds every third hour per 24 hours over a period of several months). The second study, with a near-continuous recording (25 seconds every 3 minutes during 24 hours for a period of five days in July) focuses on the moose’ selection for browse on the island of Vega, Norway. I have also compared the foraging frequency of browsers (the Vega moose) with that of grazers (dairy cows, using published data). An overall question throughout the projects has been whether video collars are a technology suitable for foraging studies of deer species and to what taxonomic resolution the cameras are able to capture the plant species. Study one was successful in showing that the camera collars are capable of showing that moose are browsers, with a low percentage of graminoids in their diet. It also managed to capture the difference in foraging choice of both moose and red deer, as well as the low diet overlap between the species during the summer months. Study two showed the moose’ clear selection for browse even during the summer, despite the rather low abundance of browse compared to non-browse in their home range. It also showed that browsers indeed have more foraging bouts (6) per 24 hours than grazers (3). The overall conclusion is that video collars are indeed suitable for studying foraging behaviour in deer and that even the short recordings are able to show intraspecific differences – at least when it comes to common behaviour. Near-continuous recording is, however, more useful for capturing individual differences, both when ...