Curation of digital biological records substantially increases knowledge of the distributions of rare and endemic species

Research‐quality distributional records remain sparse for most insect species despite high and increasing levels of citizen science recording. A challenge is to upgrade unidentified or incorrectly identified online observations to research‐quality records. Taking seven species of skipper butterflies endemic to montane regions of Costa Rica and Panama, this study considers the extent to which additional potential research‐quality records might exist: as photographs uploaded to iNaturalist (not identified to species, identification not confirmed or incorrectly identified), from online museum records and other sources that could complement existing data in the Global Biodiversity Information Facility (GBIF). The curation process took approximately 1.5 to 2 person days of effort per species, over a 44‐day period, despite limited initial knowledge by the author. Additional records were found for all seven species, and errors were found in existing records for five of them. In total, the available research‐quality records increased five‐fold: from 24 originally correct records to 123 at the end of the curation process. Although the number of records per species remains modest (2 to 50, at an average of 17.6 records per species), the additions revealed major new parts of the species distributions for all the species. Correct identifications ensure that recorders have larger numbers of accurate online images (and future computer‐assisted identifications), hence increasing the likelihood of future correct identifications. This form of curation can make major contributions to knowledge of the distributions of rare, endemic and potentially threatened species, informing research and conservation programmes.