The Effects of Culling on the Badger (Meles meles) Population in Ireland.

Abstract

The European badger (Meles meles) has also been identified as the main wildlife reservoir for bovine tuberculosis (bTB). Consequently, badgers are culled nationwide as part of the bTB eradiation scheme. The control program carried out by the Department of Agriculture, Food and the Marine (DAFM), provided an unparalleled opportunity to study the effects of long term culling on a protected mammal species. This project combined two main components: one, to investigate the effects of culling at population level, social group level and an individual level and two, to accurately predict parturition to define the most appropriate and humane closed season.

Surprisingly, and contrary to much of the published literature, repeated culling as found to have a minimal effect on the population dynamics and social group sizes of Irish badgers. The age profile of the immigrating/dispersing females was also unexpected, as it was not primarily made up of younger females but instead it was a mix of adults and aged adults. However, there were some significant differences seen between individuals in repeatedly culled areas and those from undisturbed areas. Females in repeatedly culled areas had significantly fewer blastocysts and those that did breed had significantly smaller litters. This study also determined that teat width, length and mammary gland depth change significantly with pregnancy and that reproductively active females could be distinguished from their non-breeding counterparts using these criteria early as January. With fecundity not decreasing as expected, this means that there may be ethical concerns for culling in repeatedly culled areas during the breeding season as lactating females may be culled and their cubs left to starve. This brings into questions the effectiveness of the current closed season, which would appear to be too short, at the wrong time of year and not currently implemented in all areas. A change to this current policy is strongly recommended.