Vermont Butterfly Survey

The main objectives of the Vermont Butterfly Survey were to: (1) educate and involve people in the discovery and protection of Vermont's natural heritage; (2) determine the current and historic distribution of Vermont butterfly species; (3) obtain baseline information on butterfly distribution and populations in Vermont at the beginning of this century for conservation today and comparison in the future; (4) assess the conservation status of Vermont butterfly species; (5) identify habitats of statewide and regional importance; and (6) investigate the status of Vermont butterfly Species of Greatest Conservation Need (SGCN) as designated in Vermont's Wildlife Action Plan.

The 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.

Butterflies and silkmoths were recorded as either voucher specimens (collection or photograph) or sight records (net-release, binoculars, visual-no aid). In the field each collected specimen was assigned a uniquely numbered voucher card and placed in a glassine envelope. Printed photographs were also handled in this manner after development. Digital photograph files were assigned a voucher card number and electronically transferred to VBS. An attempt was made to secure one voucher of each species in each priority block.

Data collection fell under two categories: site surveys and casual observations. Site survey forms were completed when a field worker visited a location specifically to conduct a timed survey and count of all butterflies observed, as well as to record habitat types in which they were found. Casual sightings did not require measures of time or counts of individuals seen, but simply denoted that a given species was present at a particular location on a certain date.

After six years of surveys the VBS database contained 36,121 records representing 103 species of butterflies and four giant silkmoths. Of these, 12,329 (34%) were vouchers (5,886 specimens and 6,443 photographs) and 23,792 were sight records.