Morisseau S.D. & Caro S.M. (2025) Birds foraging on human-derived foods in suburban areas. ARDEA 113 (1): 22-22

Humans have significantly impacted birds’ habits, inducing changes across many aspects of foraging behaviour. Birds eat seeds provided at feeders, help themselves to cattle feed at farms, eat insects smashed on cars, feast on leftovers in the garbage, even swoop in to steal ice cream cones at the beach. These human-provided foods vary from natural to ultra-processed (food made via industrial factories using manufactured ingredients). How much birds eat ultra-processed foods and how exposure to processed foods impacts avian dietary choices, should be investigated. Additionally, most studies on urbanization compare behaviour at extremes of highly urban or highly rural, leaving suburban environments relatively understudied. We therefore investigated wild birds’ feeding behaviour at two suburban sites on Long Island, New York: a university campus and a bird sanctuary. We provided unprocessed food (sunflower seeds, milo, millet and cracked corn), minimally processed food (dryroasted peanuts) and ultra-processed food (peanut butter protein bars). We observed more birds feeding on the unprocessed food at both sites, perhaps implying a preference for natural or familiar foods. Campus birds were observed eating the peanut butter protein bar and roasted peanuts more than sanctuary birds. These results suggest that while birds are more likely to eat natural foods, they also exploit processed and ultra-processed foods. Overall, our study sheds light on how birds forage on human-provided food in suburban areas and offers a guide for future studies combining data from multiple field sites or investigating how foraging behaviour changes over time with exposure to anthropogenic food.