The broader isotopic niche of Long-tailed Duck Clangula hyemalis implies a higher risk of ingesting plastic and non-plastic debris than for other diving seabirds

Highlights: • Plastics were the most common debris type in the Baltic seabirds. • First record of Long-tailed Duck ingestion of plastic and other debris. • Scoters, the most abundant species, had not swallowed any debris. • Large ingestion of debris of Long-tailed Duck might be linked to a broad isotopic niche. This study presents the first data relating to debris ingestion by diving seabirds wintering in the south-eastern Baltic Sea, sets baselines for further studies and presents the first global record of plastic ingestion in Long-tailed Duck (Clangula hyemalis). Three of the six studied seabird species, and 2.1% of all 524 examined individuals collected from fishery bycatch, had ingested marine debris. Frequency of ingestion of Long-tailed Duck, Common Murre (Uria aalge) and Red-throated Loon (Gavia stellata) were 5.0%, 4.5% and 3.0% debris respectively, dominated by plastic objects. Providing detailed information about the studied individuals and the debris, this initiates discussion about diving birds' sensitivity to marine debris - it may depend on the feeding preferences of the birds, expressed as isotopic niches in this paper.