Citizen-science data identifies the daily movement patterns and habitat associations of a nocturnal urban-invading bird species (Corvus frugilegus)

Abstract

Rooks (Corvus frugilegus) are an invasive bird species in South Korea that are deemed harmful due to nocturnal urban invasions and agricultural damage. Employing citizen science data, we document the daily movement patterns and habitat associations of nocturnal urban-invading rooks in Suwon, South Korea. We collected 4,522 geolocated observations from December 2021 to March 2022, categorized by the timings of sunrise and sunset and segmented into 3-h intervals. Using the MaxENT (Maximum Entropy Model) and k-fold cross-validation (k = 10) with a 25% random test sample, we analyzed daily movement patterns and habitat preferences. Our results show that rooks forage in agricultural areas shortly after sunrise and roost in urban environments after sunset. Urban roosts tend to occur in areas near buildings of medium height (6–20 stories) that are illuminated by artificial light and contain utility poles. The variables with the highest percent contribution to rooks’ presence after sunset were buildings of medium height (20.7%), land use type (19.4%), elevation (29%), and utility pole (14.5%). Our findings emphasize the potential of citizen science initiatives to generate insights into the ecology of invasive bird species within large urban environments.