Nature Today | Butterflies: formerly collections, now tools, internet and books

Thanks to the tools, internet sites and books that are now available, the total number of observations has increased enormously. That is why we now have a good idea of ​​where each species occurs. In the past, this was much more unclear for many species. The oldest documented sighting of a moth – an oleander pintail – in the most complete moth database Noctua, dates back to 1672 in Soest! From that point on, the number of documented sightings did grow, but of course much less than today. Many of the older observations concern butterflies that have been collected, as pinning used to be much more common among butterfly watchers. In case of doubt about the species, in case of discovery of a beautiful specimen of a species or in case of rare and remarkable sightings, the butterfly was taken away and pinned up for further study at home. In addition to these collections, many observations from the field were written down in special observation booklets. Just like how it is done online now, what was observed was systematically written down for each visit. Nowadays it is no longer necessary to pick up a butterfly to have proof of a sighting, taking a photo is a lot easier and often sufficient.

There are still gaps in knowledge about the distribution of many species of butterflies, especially from a long time ago. A lot of pre-internet observations have already been digitized, but there is still much to be gained in that area. Many collections are still privately managed or owned and the observations have never been entered digitally. Species used to occur in places where they no longer occur. This old distribution data can use statistics to provide insight into which species have progressed or declined. This data can, for example, be used to draw up an official Dutch Red List of Moths, looking back to a reference period of around 1950.

“Do you have any collection or notebooks?”

We can use your help in increasing knowledge about the distribution of both moths and butterflies. If you have an old butterfly collection at home or a booklet with written observations of yourself or your parents or grandparents, we would like to receive the data for research. The most important information we need for this is the name of the observer, the species name (Dutch and scientific) of the butterfly, the exact location of the observation and the date (day/month/year). Hopefully we will get an even better picture of the spread from the past in the future! The more observations available, the better the picture of the distribution of a species.

Text: Matijs Moree & Jurriën van Deijk, De Vlinderstichting
Photos: Matijs Moree
Chart: NDFF