Use of Supplementary Feeding Dispensers by Arctic Foxes in Norway

Abstract

Supplementary feeding is often used as a conservation tool to reverse the decline of foodlimited populations. The arctic fox (Vulpes lagopus) is one of the most endangered mammals in Norway and has been the target of several conservation initiatives for almost 3 decades, including supplementary feeding. To measure and improve the efficiency of supplementary feeding as a conservation action, we used passive integrated transponder (PIT)-tags in arctic foxes and 6 feeding stations equipped with PIT-tag readers to monitor individual use of supplemental food between 2013 and 2018. We tested hypotheses about the potential influence of temporal and spatial patterns, individual characteristics (i.e., age, sex, reproductive status), and food abundance (abundance of small rodents and amount of food filled) on the frequency and intensity of use of supplementary feeding stations by arctic foxes. The feeding stations were visited ≥1 time by 196 PIT-tagged individuals. We detected 54% of juveniles born in the study area between 2013 and 2017 at the feeding stations. More arctic foxes used the feeding stations during the pre-breeding period than during the other seasons, and the visits occurred mostly at night. The closest feeding station to each natal den was systematically used by the established pair and by the juveniles born at this den. Juveniles did not use the feeding stations more than adult foxes. Older foxes, and breeding adults, visited the feeding stations more than younger and non-breeding adults. Foxes used feeding stations more intensively when prey was scarce and with greater amounts of supplemental food. This study highlights that supplemental feeding is important for breeding adults, especially in periods of low prey abundance. Understanding the use of feeding stations will contribute to the optimization of supplemental feeding as a conservation action and help wildlife managers to carefully plan and manage its discontinuation.

Fecal glucocorticoid metabolites as an indicator of adrenocortical activity in Arctic foxes (Vulpes lagopus) and recommendations for future studies

“…The mean time to reach peak concentrations following treatment was approximately 10-12 h, indicating that the adrenocortical activity was higher in the foxes during the night. That could be due to the fact that the Arctic fox is mostly nocturnal, using more energy during night (Thierry et al 2020), with, thus, a corresponding increase in adrenocortical activity. There was however, large individual variation in the time to reach peak concentration, varying from 4 h to 24 h. This difference could partly be explained by variation in metabolic rate.…”

Resources and predation: drivers of sociality in a cyclic mesopredator

“…Feeding stations were installed within 150 m from den sites, primarily after a litter was born in the den for the first time (occasionally when den site was observed to be frequently visited) and kept active even if the den was deserted in following years. Supplementary food was always consumed but to a lower extent with increasing rodent abundance, indicating that foxes prefer natural prey (Thierry et al 2020 ; personal observation). Since group-living has been shown to be more common in areas with frequent supplementary feeding (Elmhagen et al 2013 ), we focused on the 146 litters with feeding and excluded three unfed litters from the analysis.…”

A camera trap‐based assessment of climate‐driven phenotypic plasticity of seasonal moulting in an endangered carnivore

“…Snøhetta is now home to one of the largest subpopulations of Arctic foxes in Norway, still supported by supplementary feeding (Eide et al., 2020; Ulvund et al., 2021). As part of the extensive monitoring scheme in place in the area, motion‐triggered wildlife camera traps (PC800 HyperFire semi‐covert camera trap, Reconyx Inc., Wisconsin, USA) were mounted on supplementary feeding stations in proximity to active Arctic fox dens (see Landa et al., 2017; Thierry et al., 2020). We used pictures and video footage from a recurring time frame from April to August 2011–2018 to identify and extract the date at which visiting foxes were reaching different stages of moulting.…”