Unconventional bird predators are relevant to vertebrate trophic relationships? A community science platform helps to answer this question.

Birds stand out among animal predators due their high species diversity and ecological flexibility. In a restrictive sense, bird predators include species that had vertebrate meat as main food item (conventional bird predators). However, insectivores, frugivores and omnivores birds occasionally include vertebrates in their diets (unconventional bird predators). Here, we use photographs posted in a community science platform (wikiaves) to examine the importance of conventional and unconventional bird predators to the trophic structure of Neotropical vertebrate assemblages. After detailed inspection of 71,285 photographs, we built a database of 6553 feeding events from 640 species distributed in 32 bird families. Vertebrates are part of the diet of 92 species of conventional and 91 species of unconventional bird predators. As expected, diets of conventional bird predators are predominantly composed of vertebrates (84% of feeding records, n = 1689), although invertebrates were also relevant for diets of owls, hawks and herons. In contrast, vertebrates comprised only 8% of feeding records (n = 358) among the unconventional bird predators. The contribution of vertebrates to diets of unconventional bird predators was relevant (> 10% of feeding records) in five of 24 analyzed bird families. Fishes, mammals and birds are the main preys of conventional predators, whereas unconventional predators focusing on ectothermic vertebrates (amphibians and reptiles). Unconventional predators expand the diversity of local vertebrate predators and consume distinct preys compared to conventional predators. Therefore, families of unconventional bird predators must be considered relevant to food web analysis of Neotropical vertebrate assemblages.