Lynx urine improves the selectivity of bait intake by red foxes

    A study reveals that lynx urine can be used as a lure to improve the consumption of baits by red foxes while minimizing its consumption by other species. This advance may improve the cost-effectiveness of the application of baits for conditioned aversion, vaccination or camera trapping.

    The use of baits to reduce the incidence of diseases such as tuberculosis through vaccination, or to produce conditioned aversion in conflicts generated by predation, is widespread worldwide. However, baiting programs are often not successful enough owing to the fact that large amounts of baits are consumed by non-target species, causing an increase in the quantity of baits to be used and consequently in the associated costs.

    Therefore, the use of baits requires new approaches to improve selectivity in application methods. In this regard, it is necessary to explore the possibility of using specific attractants or lures to improve the intake of baits by the target species while minimizing the intake by non-target species of baiting campaigns.

    The baiting of red foxes has various applications in the field of population management, including their vaccination, the generation of conditioned aversion to prey to reduce conflicts generated by predation and camera trapping.

    Scientists from the Research Group in Game Resources and Wildlife Management and the Research Group in Wildlife Toxicology of the Instituto de Investigación en Recursos Cinegéticos (IREC – CSIC, UCLM, JCCM) have evaluated two lures used in carnivore studies to improve the likelihood of bait intake by red foxes and minimize the bait intake by non-target species.

    To do this, non-toxic baits were distributed across 1,000 ha and their intake was monitored by camera traps during 3-week trials. Baits were assigned to two treatments with odorous lures (lynx urine and a mixture of fatty acids - FAS) and one control.

    Results showed that adding lynx urine near the baits (1-2 m) significantly increased the bait intake by red foxes (58.8%) compared with control (5.7%) and FAS treatment (16.7%). Bait intake by non-target species was lower in the lynx urine treatment (23.5%) than in the control (54.7%) and also with respect to the FAS treatment (36.7%).

    The probability of bait persistence after the 3-week trial differed significantly among treatments, being lower in the lynx urine treatment than in the treatment with FAS and the control. All baits consumed by foxes with the lynx urine treatment (58.8%) occurred within the first 10 days, whereas intake by non-target species (23.5%) stopped after day 7.

    Lynx urine improved bait intake by red foxes (a) and reduced the consumption of baits by non-target species (b).

    Using odorous lures such as lynx urine increases the proportion of baits consumed by red foxes while minimizing the amount of baits available for non-target species. On the other hand, the persistence of baits in the environment can also be reduced, thus minimizing the risk of bait consumption by non-target species and reducing application costs. Therefore, lynx urine or other odorous attractants can serve to optimize the baiting methods for red foxes in their different applications, such as studies of conditioned aversion, vaccination or camera trapping.

    The scientific publication of this research is available at: