Comparative study on the consequences of culling badgers (Meles meles) on biometrics, population dynamics and movement

1. Capture-mark-recapture data were used to describe the process of recovery from a typical badger removal operation (BRO) at North Nibley, Gloucestershire, UK, which was carried out as part of the government's strategy to control bovine tuberculosis. Data on biometrics, demographics and movement from this low-density disturbed population were compared with those of two nearby high-density undisturbed populations (Wytham Woods and Woodchester Park, UK) in order to study fundamental principles of population dynamics and density-dependence. 2. Badgers moved more between social groups at North Nibley than in the other study areas, particularly in the immediate aftermath of the removal operation. 3. Recolonization of the vacated habitat occurred in the first instance by young females. 4. Although in the first year after the BRO no cubs had been reared in any of the culled groups, and although the shortage of sexually mature boars may have limited the reproductive output of sows in the following year, the population took only 3 years to recover to its (already lowered) preremoval density. 5. Losses from the adult (and cub) population due to mortality or emigration were smaller at North Nibley than at the other sites. 6. There was much evidence that during 1995 and 1996 density-dependent effects constrained the reproductive output of the high-density populations, and some support for the hypothesis that badgers exhibit the non-linear `large mammal' type of functional response to density. 7. Badgers at North Nibley were younger, heavier and in better condition than badgers at Wytham Woods and Woodchester Park. 8. We argue that the disease dynamics are likely to be different in disturbed compared with undisturbed badger populations, and that this could affect the effectiveness of BROs.