Summary1. Culling wildlife hosts is often implemented as a management technique to control pathogen transmission from wildlife to domestic or other economically important animals. However, culling may have unexpected consequences, can be expensive and may have wider implications for biodiversity and ecosystem functioning. 2. We assess the evidence that culling mountain hares Lepus timidus is an effective and practical way to control louping ill virus in red grouse Lagopus lagopus scoticus. 3. Evidence from the available literature is limited, restricting our ability to reliably assess the effectiveness of culling mountain hares to control ticks, louping ill virus, or increase red grouse densities. Furthermore, the information required to assess the cost-benefit of this management strategy is lacking. The population response of mountain hares to culling is not well understood and the possible effects on their conservation status and the upland ecosystem remain unexplored. 4. We conclude that there is no compelling evidence base to suggest culling mountain hares might increase red grouse densities. 5. Synthesis and applications. Widespread culling of wildlife is not necessarily effective in reducing disease or improving economic returns. The use of wildlife culls for disease control should be proposed only when: (i) the pathogen transmission cycle is fully understood with all host-vector interactions considered; (ii) the response of wildlife populations to culling is known; and (iii) costbenefit analysis shows that increased revenue from reduced disease prevalence exceeds the cost of culling.

Estimating density, age and sex structure of wild populations is a key objective in wildlife management. Live trapping is frequently used to collect data on populations of small and medium-sized mammals. Ideally, sampling mammal populations by live capturing of individuals provides a random and representative sample of the target population. Trapping data may, however, be biased. We used live-capture data from mountain hares Lepus timidus in Scotland to assess sampling bias between two different capture methods. We captured hares using baited cage traps and long nets on five study areas in the Scottish Highlands. After controlling for the effects of body size, individuals caught in traps were lighter than individuals caught using long nets, suggesting that the body condition of hares differed between the capture methods. This tendency may reflect an increased risk-taking of individuals in poorer body condition and less aversion to entering traps in order to benefit from eating bait. Overall, we caught more adult hares than juveniles and more female hares than males. Our results show that estimates of density and population structure of mountain hares using livecapture data could be affected by the capture method used. We suggest that live-capture studies employ more than one capture method and test for heterogeneity in capture probability to minimise potential bias and achieve reliable estimates of population parameters.