Spatio-Temporal Changes in Rook’s Assemblage Revealed by Thousands of Citizen Science Photos

Abstract Citizen science data are increasingly being used to address ecological challenges. In our study, we utilized these data to analyze the urban invasion of rooks (Corvus frugilegus), which posed sanitary concerns and caused disruptions for residents. Although various strategies exist to contain rook invasions, effective mitigation relies on understanding their habitat preferences and daily movements—information hard to gather over extensive areas. To address this, we collected 4,523 geolocated observations from citizens who were monetarily incentivized to photograph the birds. These observations were categorized based on sunrise and sunset timings and further divided into 3-hour intervals. Our analysis revealed that rooks ventured to agricultural areas for foraging after sunrise but predominantly settled within the city post-sunset. During roosting, rooks displayed a preference for environments mimicking forested habitats, likely seeking protection from predators and adverse environmental elements like wind and extreme temperatures.