Urbanization and Seasonality Increase Introduced Plant Consumption by the World's Southernmost Parrot

ABSTRACT Urbanization and the introduction of plant species can alter food source dynamics and affect plant–animal interactions; thus, wildlife persistence in novel ecosystems depends on behavioral plasticity. Changes in food availability can be particularly relevant in temperate forests, where seasonal resource depletion represents a major challenge to resident animals. Here, we aim to understand how these environmental challenges affect habitat and food use by the southernmost parrot, the Austral parakeet ( Enicognathus ferrugineus ), which lives in forests from southern South America. For this, we (1) describe seasonal foraging dynamics and (2) evaluate the use and selection of food plants. In a gradient of urbanization in northwestern Patagonia, Argentina, we surveyed foraging parakeets, and documented plant resource availability and phenology throughout the year. Parakeets consumed three times as many introduced as native plant species in urban environments, mostly during winter, when native food availability is scarce. Whereas the opposite pattern occurred in natural areas. Resource use and selection varied with environment and sampling scale, including the selection of native species in urban areas and introduced species in natural environments. By revealing broad patterns of plant–animal interactions across contrasting environments, we illustrate how urbanization reshapes habitat and resource use in a behaviorally plastic species. We also provide phenological data relevant to a range of co‐occurring species. Our findings underscore the trade‐offs associated with urbanization for wildlife. We highlight the need to promote native vegetation to avoid introduced species potential spread into natural ecosystems, and to comprehensively assess the ecological role that introduced plant species are playing in avian nutrition and urban ecosystem functioning.