Badgers Identified as Primary Driver of Hedgehog Decline in UK
New analysis suggests that the growing badger population, not commonly cited factors like roads or pesticides, is the main threat to Britain's hedgehogs.
The decline of Britain's hedgehog population is largely attributable to the increasing numbers of badgers, according to a new analysis that challenges commonly held beliefs. While factors such as roads, pesticides, and habitat loss are frequently blamed, evidence suggests that badgers are the primary predator responsible for the dwindling numbers of these native mammals.
Studies and observations across the United Kingdom indicate a strong correlation between rising badger populations and declining hedgehog numbers. In locations such as Kew Gardens, hedgehogs disappeared as badger activity increased. Similarly, at Wytham Woods, introduced hedgehogs were quickly preyed upon by badgers. In contrast, hedgehogs thrive on Scottish islands where badgers are absent, such as South Uist and Islay, even becoming a pest in some instances.
Scientists point to a "mesopredator release problem," where the absence of top predators allows middle-ranking predators like badgers to flourish and negatively impact their prey. The current high density of badgers in Britain is attributed to a lack of natural predators, an abundance of human-provided food sources, and legal protections.
Historically, numbers of hedgehogs may have been exaggerated. A commonly cited figure of a 97% decline from 30 million in the 1950s is now considered a myth. More recent estimates suggest numbers have roughly halved, with the most significant decline occurring since the 1990s.
Direct evidence from badger culls conducted to control bovine tuberculosis has shown a rebound in hedgehog populations in affected areas. In "amenity grassland" within cull zones, hedgehog density increased significantly over five years, while remaining unchanged in areas without culling. This suggests a direct impact of badger predation on hedgehog numbers.
While pesticides and traffic do pose some risks, they are considered secondary to predation by badgers. Insecticide use has generally decreased, and hedgehogs are disappearing even in areas with low chemical usage. Furthermore, hedgehogs are often found in higher densities in busy suburban areas, contradicting the idea that traffic is the primary cause of their decline.
Badgers are also impacting other species, such as bumblebees, by preying on their nests. The analysis concludes that without effective badger population management, the continued decline of hedgehogs and other vulnerable species is likely.