THE EFFECT OF REDUCTION IN BADGER DENSITY ON THE SPATIAL-ORGANIZATIONAND ACTIVITY OF BADGERS MELES-MELES L IN RELATION TO FARMS IN CENTRALIRELAND

The relationship and overlap between farms and territories of badger s ocial groups were determined in an area of central Ireland which has a chronically high incidence of tuberculosis in cattle. Badger territor ial boundaries were determined by the bait-marking technique, and all signs of badger activity, setts, latrines and paths were mapped in an area of 16km(2). Farms were highly fragmented and consisted of between one and eight parcels of land. As a result a farm shared a boundary w ith between four and sixteen contiguous farms. The proportion of herds infected with tuberculosis fluctuated between 7.4% and 29.6% over the three-year study. Badger territories were, on average, almost three t imes larger than the area of the average farm. The fragmentation of fa rms further increased the degree of overlap. The territory of a badger group overlapped in whole or in part between six and fourteen differe nt farms. Most (75%) of the badger groups contained at least one infec ted individual during the study. Every herd was either contiguous to l and used by an infected herd or shared pasture with badgers from an in fected social group. Overall, cattle had open access to most sites par ticularly used by badgers, such as setts and latrines. Because of the highly non-random distribution of those sites, erection of cattle-proo f fencing along farm boundaries will substantially reduce access by ca ttle without concomitant loss of productive land. Culling of an estima ted 50% of the badger population resulted in an increased potential of cattle-badger contact as assessed by the number of farms visited by e ach group of badgers and an increase in the number of badger soups vis iting particular farms.