Perspectives and challenges on isotopic ecology of terrestrial birds in Brazil

. Although stable isotopes have been increasingly used in ornithology since 1980 in many places, Brazil has been slow in adopting this methodology, especially when it comes to terrestrial birds. The most common elements in bird ecology studies are carbon, nitrogen, hydrogen, and oxygen stable isotopes, which provide information on diet, trophic interactions, habitat use, migration, geographic patterns, and physiology. It is important that Brazilian ornithologists become aware of the potential of stable isotope analysis in ecological studies, and the shortcomings of this tool. The use of stable isotopes to study bird ecology has great potential in Brazil, since many ecological questions about Neotropical birds can be addressed by it (e.g., resource and habitat use, migratory routes, isotopic niches, anthropogenic impacts, individual specialization). Brazilian museums and other Natural History collections can provide samples to study long-term temporal dynamics in bird ecology. Additionally, the integration of avian tissue sample information into a database may increase the collaboration among researchers and promote sample reuse in a variety of studies. All biomes in Brazil have been under pressure from anthropogenic impacts (e