Moberly, R.L., P.C.L White, C.C. Webbon, P.J. Baker, and S. Harris. 2003. Factors associated with fox (Vulpes vulpes) predation of lambs in Britain Wildlife Research 30: 219-227

Abstract
Red foxes (Vulpes vulpes) are believed to have an economic impact on farming through predation on lambs, poultry and game. Investigation of the causes behind variation in the impact of predation between farms is required to improve management of these problems. A questionnaire survey of sheep farmers was combined with field data on relative fox population abundance to investigate some of the factors associated with both the occurrence and scale of perceived fox predation in Britain. Reported lamb losses to foxes were generally low but there was a large range in perceived levels of predation, from 0.0008 to 0.26 lambs per ewe, with 59% of respondents reporting that they had lost at least one lamb to a fox at their most recent lambing. Flock size was an important factor determining perceived fox predation. Fox predation was more likely to have occurred on larger farms, but, when it did, fewer lambs were perceived lost per ewe. Various other non-management characteristics, including regional location, had an influence on fox predation. Fox abundance was positively associated with perceived predation. Indoor lambing was an important preventive measure against fox predation. However, the effect of fox control on livestock predation was difficult to determine because of potential reactive behaviour by farmers to lamb losses. The analyses indicate that multivariate rather than univariate techniques should be used in the assessment of predator impacts and in making management recommendations. The identification of farm characteristics associated with fox predation, such as location and indoor lambing, enables the potential identification of problem farms where preventive management should be targeted.