From 2002 to 2007 volunteer butterfly enthusiasts spent thousands of hours in the field in an effort to record the status and distribution of Vermont butterflies. Coupled with this survey was an effort to record all sightings of giant silkmoths that were found. This effort continues today as naturalists find and report their sightings via iNaturalist Vermont.
During the butterfly atlas, data was collected within a grid based on USGS topographic quadrangles. Each quad was divided into six equal blocks for a total of 1,104 blocks. Each block was approximately three square miles. One block from each quad was randomly selected as the priority block for a total of 184 priority blocks. There was no statistical difference in the percent coverage of priority blocks within each biophysical region.
Participants attempted to verify the presence of as many species as possible within each block, noting a variety of other data with each record. The result is the most detailed database of the spatial and seasonal distribution of Vermont butterflies ever compiled.
This survey represented a “snapshot” in time of Vermont silkmoth distribution. This is the primary function of a biological atlas for conservation purposes—to set a baseline against which successive future surveys can be compared. Silmoth populations, like other organisms, are not static but change in status as a result of land use change, adapting to new food plants, climate change, and other factors.