Unforeseen Effects of Supplementary Feeding: Ungulate Baiting Sites as Hotspots for Ground-Nest Predation

Abstract

Despite the ubiquity and magnitude of food provision to wildlife, our understanding of its ecological effects and conservation implications is very limited. Supplementary feeding of ungulates, still one of the main paradigms of game management in Europe, occurs in natural areas on an enormous scale. We investigated the indirect effects of this practice on nest predation risk in the Polish Eastern Carpathians (Bieszczady Mountains). We hypothesized that the predators attracted to ungulate baiting sites would also forage for alternative prey nearby, increasing the nest predation risk for ground-nesting birds in the vicinity. We conducted a paired experiment by placing artificial nests (N = 120) in feeding and control sites (N = 12) at different distances from the ungulate feeding site. We also documented the use of three ungulate feeding sites by potential nest predators with automatic cameras. The proportion of depredated nests was 30% higher in the vicinity of feeding sites than at control sites (65%±31.5 vs 35%±32.1). The probability of a nest being depredated significantly increased with time and at shorter distances from the feeding site. We predicted that the area within 1-km distance from the feeding site would have a high risk (>0.5) of nest predation. We recorded 13 species of potential ground-nest predators at ungulate baiting sites. Most frequent were Eurasian jays Garrulus glandarius, mice and voles Muroidea, ravens Corvus corax, brown bears Ursus arctos, and wild boar Sus scrofa. Nest predators made most use of supplementary feeding sites (82% pictures with predators vs 8% with ungulates, the target group). Our study alerts of the impacts of ungulate feeding on alternative prey; this is of special concern when affecting protected species. We urge for a sensible management of ungulate feeding, which considers potential indirect effects on other species and the spatial and temporal components of food provision.

Diversionary feeding: an effective management strategy for conservation conflict?

“…Studies using artificial bird nests suggest increased predation of groundnesting birds adjacent to 'vulture restaurants' (Cortés-Avizanda et al 2009) and deer feeders (Cooper and Ginnett 2000), with a 30 % increase in the predation of artificial ground nests in close proximity to deer feeders in Poland (Selva et al 2014). Similarly, trials to quantify predation of artificial turtle nests showed that scavengers attracted to deer feeding stations resulted in a five-fold increase in predation rates on artificial nests (Hamilton et al 2002).…”

Supplementing non‐target taxa: bird feeding alters the local distribution of mammals

“…, Selva et al. , Hanmer et al. ), particularly for bird species that do not directly benefit from the resource but may suffer the consequences of increased risks of nest depredation.…”

Fast food bears: brown bear diet in a human‐dominated landscape with intensive supplemental feeding

“…Here we consider supplemental feeding to include also baiting (i.e. feeding for the purpose of attracting or/and capturing wildlife), since in many areas (especially in Europe) feeding is often used simultaneously for several purposes (Kav č i č et al 2013, Selva et al 2014). Supplemental feeding is commonly used in wildlife management and conservation.…”