Using lures for improving selectivity of bait intake by red foxes

Abstract

Abstract Context The use of baits for reducing the populations of harmful animal species, eradicating invasive species, vaccination, contraception or producing conditioned aversion, is widespread worldwide. However, baiting programs are often not successful enough and affect non-target species, requiring new approaches for baiting methods. Aims The aim of the present study was to evaluate two attractants used in carnivore studies to improve bait intake probability by red foxes and minimise bait intake by non-target species. Methods Non-toxic baits were distributed across 1000 ha, with bait intake monitored by camera traps during 3-week trials. Baits were assigned to two treatments with lures (lynx urine and Fatty Acid Scent – FAS) and one control. Bait intake by red foxes and non-target species was analysed using Generalised Linear Mixed Model (GLMM) and Kaplan–Meier survival analyses. Key results Lynx urine significantly increased the bait intake by red foxes (58.8%) compared with control (5.7%) and FAS (16.7%) treatment. However, FAS did not significantly increase the bait intake by red foxes compared with control. Bait intake by non-target species differed significantly between treatments, with lower intake in lynx urine (23.5%) treatment than control (54.7%), but not regarding FAS (36.7%), and neither between FAS and control. The probability of bait persistence after the 3-week trial period differed significantly among treatments, being lower in lynx urine treatment (0.18) than FAS (0.50) and control (0.43). All baits taken by foxes with lynx urine treatment (58.8%) occurred within the first 10 days, whereas intake by non-target species (23.5%) stopped after Day 7. Conclusions The use of lynx urine lure increased the proportion of baits consumed by red fox and reduced bait intake by non-target species. Implications Lures can serve to optimise bait delivery methods for red foxes in their different applications, such as conditioned aversion studies, vaccination, live trapping or predator control, while minimising risks to non-target species and reducing the costs and application time.