Multilocus barcoding confirms the occurrence of Elegant Terns in Western Europe

We used sequences from one mitochondrial gene and six nuclear loci to confirm genetically the presumed identity of four large terns with an orange bill seen in Western Europe over the past decades. This multilocus genotyping (multilocus barcoding) approach confirmed that one bird was a Lesser Crested Tern Sterna bengalensis , as suspected based on its phenotype, and identified the three other birds as pure Elegant Terns Sterna elegans . This last result was again in accordance with the appearance of these birds even if their identity had long been considered as unproven. In comparison with traditional (single-locus) barcoding, our approach allowed us to unambiguously exclude that these birds were first-generation hybrids or backcrosses involving Elegant Terns or other species of orange-billed terns.