Marine debris ingestion by adults and fledglings of Swinhoe's storm petrels in the Republic of Korea

Procellariiformes are highly vulnerable to marine plastic pollution due to their species-specific life histories. In particular, storm petrels are known to be one of the most vulnerable species with respect to plastic ingestion. In this study, we examined the plastic ingestion by adults and fledglings of Swinhoe's storm petrels on Chilbal Island, one of the largest breeding colonies for this species. During 2013 and 2014, we collected adult and fledgling carcasses and analyzed their stomach contents. The results showed that both adults and juveniles were consuming mostly plastics. Most of the collected Swhinhoe's storm petrels were consuming microplastic, with juveniles consuming a higher average amount of plastic than adults. The type of plastic ingested was more threadlike in adults and fragments in juveniles. In conclusion, the characteristics of ingested plastics differed between adults and juveniles, suggesting that analyzing individual age may be important for monitoring plastic ingestion in the future. •98 % of adults and 100 % of fledglings ingested plastic debris.•Fledglings ingested more plastic debris than adults in numbers and mass.•63 % of fledglings and 24 % of adults contained >0.1 % of average body mass.•Adults contained longer and threadlike plastic debris than fledglings.•Polyethylene (50.1 %) and Polypropylene (43.2 %) were dominant.