'Who Goes There?' Quantifying Scavenger-Carcass Activity at Mass Mortality Events

Mass mortality events (MMEs) create sudden pulses of carrion that can alter how vertebrate scavengers use carcass resources, including the frequency, duration, and timing of species-carcass contacts. These changes could have implications for pathogen transmission at the scavenger-carcass interface. We aimed to develop and apply a reproducible analytical framework for using camera-trap data to quantify transmission-relevant vertebrate activity at carcass sites under differing carrion biomass scenarios. We studied experimental carcass plots (single carcass ~43 kg; 'mass mortality' plots [10 carcasses, >350 kg total]; 6 of each) in Australia's alpine ecosystem. The framework integrated descriptive summaries (bipartite network analysis, Kaplan-Meier curves) and marked temporal point-process models to characterise structural and temporal dimensions of species-carcass activity. Mass mortality plots had greater overall visitation duration, occurring as sustained activity (50% of visitation event volume by day 17), compared with intense then rapidly declining activity at single carcasses (50% by day 8). Mass mortality plots also had higher predicted daily arrival probability and contact hours across most species, indicating an extended window for pathogen transmission. This framework provides empirically derived contact parameters for MME-related disease spread models using camera-trap data to identify potential transmission pathways at the scavenger-carcass interface.