In the footsteps of city foxes: evidence for a rise of urban badger populations in Switzerland

摘要

Single observations of badgers in urban areas have been interpreted as relicts of formerly rural populations that have merely survived urban encroachment. However, decades after the rise of urban fox populations in continental Europe, there is evidence from Switzerland which suggests that badgers may be following a similar trend. We present long-term traffic casualty data, a comparison over time of camera trap studies, and incidental observations collected in a Swiss citizen science project which indicate both an increase of badgers at the national scale as well as a range expansion into urban areas. Their rather delayed and slow increase, compared to foxes, might be based on slower reproduction and less flexible behavioural adaptations. Our data, however, suggest that badgers are recovering delayed from a population depression following the rabies epizootic of the 1960s and 70s and may be starting to expand their range through the colonisation of urban habitats, similar as foxes did during the 20th century.