Opportunistic Foraging in Changing Insular Landscapes: Trophic Ecology of the Azores Woodpigeon ( Columba palumbus azorica )

Human activities have caused major transformations to many oceanic islands worldwide, driving native species to adapt their foraging behavior to altered resources. While such trophic plasticity enables animals to persist in unstable and modified environments, it also disrupts established trophic interactions and alters ecosystem dynamics. Columbids (pigeons and doves) often dominate avian frugivore guilds on oceanic islands and play a crucial role in ecosystem functioning through their seed dispersal services. However, understanding how environmental pressures shape trophic interactions has received little attention. We investigated the trophic ecology of the Azores woodpigeon (Columba palumbus azorica), an endemic subspecies of the Azores archipelago, using DNA metabarcoding on fecal samples collected on two islands, to clarify its ecological role and assess how seasonal variations and land-use changes affect diet richness and composition. Our results reveal a diversified diet composed of a wide range of herbaceous and woody plants, with 159 plant taxa detected across 450 samples. Despite the almost complete disappearance of pristine habitats, native plants remain a significant part of the diet, but exotic and cultivated species are largely consumed, suggesting strong limitations in natural resources. As expected, we observed marked seasonal variations in diet, likely related to food availability, particularly of fruits. Strong spatial variations in foraging behavior were also observed as pigeons tended to be more generalist in simplified landscapes, and habitat disturbance resulted in a dietary shift from native to exotic plants. Overall, our study indicates a great trophic plasticity and opportunistic foraging behavior that provides resilience against environmental pressures, while it may threaten the regeneration of natural habitats.