Scale-Dependent Attraction of Invasive Raccoons to Bait Sites: Behavioural and Proximity Responses in a Post-Disaster...

Baiting is widely used to improve the capture and observation of invasive mesocarnivores, but it can also alter behaviour and distribution, potentially increasing ecological risks, such as non-target interactions and pathogen transmission. However, responses to baiting across temporal scales remain poorly understood. We investigated scale-dependent responses of invasive raccoons (Procyon lotor) to baiting in a post-nuclear-disaster agricultural landscape in Fukushima, Japan. We used cafeteria-style bait trials, in which multiple bait types were offered simultaneously at each station; together with GPS telemetry, we evaluated responses from bait choice to short-, mid- (daily), and long-term space use. Individual bait preferences, short-term movement responses, daily responses and long-term space use were analysed using Plackett-Luce models, hidden Markov models, minimum distance to trap sites and autocorrelated kernel density estimation, respectively. Seven GPS-collared raccoons visited bait stations, yielding 15,837 GPS locations. Bait choice varied markedly among individuals. Across trials, dry cat food (0.40) and caramel corn (0.38) had the highest first-selection probabilities, whereas dried ramen noodles were seldom selected first (0.01). Some individuals consistently preferred other bait types such as sake lees. Short-term analyses showed strong attraction to bait stations, with area-restricted search-like movements increasing from 22.2% during non-baiting periods to 53.8% during baiting. At the daily scale, raccoons moved closer to trap sites on baiting days, indicating increased proximity to management locations. In contrast, all bait stations fell within long-term home ranges and often within core areas, suggesting localised activity intensification rather than broader restructuring of space use. Overall, baiting induced strong but scale-dependent behavioural responses, with localised increases in site use but little evidence of broader restructuring of long-term space use. These findings suggest that the effectiveness and interpretation of bait-based monitoring and management may depend on both temporal and individual-specific bait preferences.