The mosaic landscape of small-scale cropping, agroforests, and secondary forests common to steep-sloped, volcanic islands in the Caribbean provide habitats and food sources for many terrestrial bird species. Information on the diets of species living in these agroecosystems can inform conservation management and land-use decisions, and reveal the ecosystem services performed by these unique island bird communities. We obtained fecal samples from 356 individuals of 14 bird species, including 3 Lesser Antilles endemics, that occur in various agroforests, pasture, and cropping habitats on the island of Grenada, May–September 2018 and January–March 2019, and determined diet items using DNA meta-barcoding analysis. Identified food items included 14 orders and 259 genera of arthropods, and 25 orders and 98 genera of plants. We found a wide mix of arthropod and plant genera across an annual cycle in every bird species studied, including those believed to be nominally nectarivorous, frugivorous, or granivorous, supporting predictions that small-island bird populations exhibit generalist foraging. Similarly, diet composition varied among species within each study site to a similar degree that diets varied among study sites within each species further indicating opportunistic/generalist foraging. In addition, we found 26 arthropod genera and 34 plant genera that were frequently shared by 3 or more bird species, suggesting the importance of specific food resources for sustaining bird communities in these heterogeneous agricultural landscapes. We also found 4 known invertebrate crop pathogens amongst 5 bird species. Together, this study reveals the various roles that these generalist species play in agroforest habitats (e.g., crop-plant pest control, pollination, seed dispersal), and the results can be used to further explore land-use practices that best provide food resources to support this unique island bird community and the ecosystem functions they carry out.

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