Using Social Media to Determine the Global Distribution of Plastics in Birds' Nests: The Role of Riverine Habitats

Plastics are widely distributed in all ecosystems with evident impacts on biodiversity. We aimed at examining the topic of plastic occurrence within bird nests. We conducted a systematic search on three social media platforms (Facebook, Instagram, and Twitter) to fill the gap of knowledge on plastic nests worldwide. As a result, we observed nests with plastics mostly belonging to synanthropic species inhabiting riverine habitats, mainly in Europe, North America, and Asia, with an increase in occurrence over the years. Two common and generalist freshwater species (Eurasian Coot Fulica atra and Swans Cygnus sp.) showed the highest frequency of occurrence of plastic debris. We suggest plastics in bird nests as a proxy for debris occurring in the environment. However, our data may be biased, due to our sample's low representativeness. Therefore, more data are necessary to have more information on plastic distribution. In conclusion, social media might be pivotal in indicating plastic hotspot areas worldwide and being an indicator of plastic pollution within the environment.