A comparison of breeding bird populations inside and outside of European Badger Meles meles control areas

The European Badger has a wide and varied diet, including birds and eggs when the availability of their preferred prey is low. Since 2012, licenses have been issued in England to permit the killing of Badgers to prevent the spread of bovine tuberculosis in cattle, and Badger populations have been controlled in large areas of the countryside. 

New research from BTO has investigated the effects of this reduction in Badger numbers on bird populations. Using data from the Breeding Bird Survey, BTO scientists analysed population trends of 58 species of UK breeding birds in the two longest-running Badger control areas in southwest England. They examined population growth over a 5-year period (2013-17), comparing to locations outside the Badger control areas, but in the same part of the country, and also comparing to a baseline period before Badger control took place (2008-12). Those bird species which are ground or near-ground nesting were analysed separately, as they are more likely to be predated by Badgers and other terrestrial predators.

The population growth rates of Skylarks and Whitethroats, both ground nesting species, were found to be slightly more positive within the Badger control areas, whereas Lapwing population growth was marginally negative in control areas. There was no significant association between the population of other ground nesting species and the Badger control areas. Of those species that nest higher up, for example in trees, Starlings, Greenfinches and Long-tailed Tits increased within the Badger control areas, whereas other species such as Woodpigeons, Linnets and Bullfinches showed decreased populations in these areas.

Overall, there was little effect of Badger removal on the population growth rates of the bird species considered in this study. Previous research has shown that Badgers only feed on birds and their eggs on occasion, and that the majority of birds consumed are already dead (carrion), so the levels of predation that do occur might not be high enough to drive bird population growth rates. The results of this study do not provide definitive evidence of the effects of Badger culling on bird populations, but they do reveal that large, community-level changes did not occur in the areas studied during the years investigated.

Notes

The authors thank the Natural England spatial data team for their help. Simon Gillings and James Pearce-Higgins provided helpful advice and Henrietta Pringle is thanked for help producing figures. Robert Hawkes, an anonymous reviewer and the associate editor provided helpful comments on an earlier version of this paper. The authors also thank Sarah Harris and Justin Walker for their help with BBS data extraction.

This study was funded by Natural England. The BBS is funded by a partnership of British Trust for Ornithology, Joint Nature Conservation Committee and Royal Society for the Protection of Birds.