The data has been collected on summer hikes in Dakota County Minnesota and adjacent areas. In 2010, after a few years of learning, it was felt that skills were good enough to identify almost all butterflies "on the wing". There are many learned attributes that help with this. Size, color, pattern are the most basic. Flight patterns and habitat are helpful. And many butterflies (e.g., the European Skipper) are only seen for a brief time. The object is to get a count of all the butterflies that are present. (There are always a few that have no clear identification -- UFOs -- Unidentified Fluttering Objects.)
The area most often surveyed is Lebanon Hills Regional Park.
No new species is considered to be identified until I have a photo.
About 20-25 species are seen in this area in a typical summer.
I am happy to talk to other butterfly enthusiasts: (952) 432-0303 or johnpf99 .at. frontiernet.net.