Winter diet of wolf (Canis lupus) after the outbreak of African swine fever and under the severely reduced densities of wild boar (Sus scrofa)

Abstract

The outbreak of the African swine fever (ASF) in Estonia in 2014 caused heavy hunting pressure on wild boar issued by authorities to stop further spread of the virus. To investigate the effects of wild boar shortage to wolf diet, we analysed 120 wolf scats from November to April in 2017-2018 from five Estonian counties and compared the results with the wolf dietary data from 1998. To eliminate possible dog scats from the material collected from areas close to settlements, genetic analysis was used. We found that ungulates still formed the bulk of the wolf diet, however, the occurrence of moose, wild boar, small rodents and hares has dropped considerably. The proportion of the roe deer and mammalian predators has increased from 51% to 55% and 4% to 10%, respectively. Moreover, plants, being totally absent in the previous study, were found in 25% of scats, in many cases representing the only food item. Food niche breadth has widened from 1.54 to 2.3. While roe deer was found to be a highly preferred, moose was still an avoided prey species.