Monitoring bait uptake in badgers: a pilot study using PIT-tag system and time-lapse video surveillance

Abstract

European badgers Meles meles are vectors of bovine tuberculosis, and may have negative impacts on the cattle grazing industry. In order to control tuberculosis in badger populations, the use of baits containing vaccines or fertility control agents has been proposed. However, in social species such as badgers, multiple bait uptake and competition for baits at baiting stations could reduce the efficiency of baiting campaigns. We used video surveillance and Passive Integrated Transponder (PIT)-tag systems to monitor the behaviour of two social groups of badgers offered plain baits. We recorded the following data: (i) proportion of baits taken by badgers/by non-target species; (ii) potential occurrence of caching; (iii) potential occurrence of bait monopolisation and competition. Badgers removed 97.8% of baits. There was no evidence of bait uptake by non-target species. Some 85% of the baits were immediately eaten at the baiting station; caching was not observed although it cannot be excluded. In 1/3 of visits, badgers consumed two or more baits. In 30% of all visits, the contemporary presence of two or more badgers searching for baits was recorded. In three instances badgers were observed to compete for baits. This study shows evidence of aggressive behaviour and direct competition for food by free-living badgers. Bait monopolisation and intra-specific competition at feeding stations could influence bait uptake and should be evaluated in other wildlife species when bait-delivered vaccines or contraceptives are used.