The Otago Museum houses one of New Zealand’s largest Lepidoptera collections that consists of more than 31,000 macro moth specimens collected across New Zealand over the last 30 years. Alongside this collection, supplementary information is found in detailed field notebooks that cover, for most sites, the total abundance of the different species present in these samples. We have been able to use the notebooks to work out the sampling intensity and sites to map both the collections and the abundances to some degree. It is impractical to collect everything. As a result, the common species are left out of collections and the rare and unusual sightings fill the collections. When planning to resample collecting sites to investigate changes in ecosystems, just relying on collections for species presence and absence would skew the results. It should also be noted that field notebooks are not a panacea for biological information as the information in them ages, so too can the reliability and accuracy of the notes within. Here we discuss how the field notebook data compares with the information accompanying the specimens housed within the museum collection. This is a recently digitised collection and allows an insight into the collectors sampling, vouchering and data practices and how these can affect modern interpretation and variation in repeat sampling.