Genetic barcoding of museum eggshell improves data integrity of avian biological collections

Natural history collections are often plagued by missing or inaccurate metadata for collection items, particularly for specimens that are difficult to verify or rare. Avian eggshell in particular can be challenging to identify due to extensive morphological ambiguity among taxa. Species identifications can be improved using DNA extracted from museum eggshell; however, the suitability of current methods for use on small museum eggshell specimens has not been rigorously tested, hindering uptake. In this study, we compare three sampling methodologies to genetically identify 45 data-poor eggshell specimens, including a putatively extinct bird’s egg. Using an optimised drilling technique to retrieve eggshell powder, we demonstrate that sufficient DNA for molecular identification can be obtained from even the tiniest eggshells without significant alteration to the specimen’s appearance or integrity. This method proved superior to swabbing the external surface or sampling the interior; however...