Checklist of the Butterflies (Papilionoidea) of Vermont, USA

The 1995 checklist of Vermont Lepidoptera listed 89 butterfly species in 48 genera (Grehan et al. 1995), with two new butterfly species recorded for Vermont. The report documented identifications primarily from specimens held at the University of Vermont Entomology Research Laboratory, the Carl T. Parsons Collection, state agencies, and private collections held by the authors. Most of the records were from collections made in northwestern Vermont. Of the 22 collecting localities, only three sites were located in the Northeastern Highlands, one in the southern third of the state, with the remainder in northwestern Vermont. The authors noted that their work should be augmented by searching for Vermont records in regional collections, as well as developing a database to document distribution, seasonality, habitat and food plants in Vermont. This spawned the Vermont Butterfly Survey which was completed from 2002 - 2007 across the entire state (McFarland and Zahendra 2010). As part of this effort, private and institutional collections, as well as published and unpublished literature and field notebooks, were searched for Vermont butterfly records. Label data from 2,377 specimens, 161 literature records and 208 visual sightings from field notebooks representing 94 species of butterflies and five giant silkmoths were found in 16 private and institutional collections, as well as in published literature, unpublished reports and field notebooks. Most records came from the UVM Zadock Thompson Natural History Collection (727), the UVM Entomological Research Laboratory (531) Scott Griggs’ personal collection (398), James Hedbor’s personal collection (263), Peabody Museum of Natural History (149; partially completed) and unpublished reports by Donald Miller (106). Hartland Nature Club, the oldest such club in Vermont, had the oldest specimens, dating back to 1892, which probably survived because of sealed Ricker mounts. After six years of surveys the VBS database contained 36,121 records representing 103 species of butterflies.

Five species with known historic occurrences were not documented by VBS. Three of these were of unknown origin or vagrants and were not expected to be recorded. These included (1) a Gulf Fritillary specimen in a collection at St. Michael’s College found road killed in Burlington on 5 May 1995 by J. Leonard; (2) a Long-tailed Skipper found nectaring on scarlet runner bean in a garden in South Hero on 6 September 1994 by James Hedbor (personal collection); and (3) a California Tortoiseshell found in southern Vermont (date unknown) by P. Opler (Scott 1986). Two formerly extant species, Regal Fritillary and Persius Duskywing, are apparently now extirpated in Vermont. The last known Regal Fritillary was a female collected on 17 July 1941 by O.M. Calloway in Pomfret, Vermont (Grehan 1995). We found the specimen in the Peabody Museum of Natural History collection. It was originally housed in the Dartmouth College collections. We also uncovered two males and a female of this species collected on 14 July 1939 in Dorset in the Peabody collection and three specimens from North Hartland (1894 and 1899, exact dates unknown) in the Hartland Nature Club collection. There is only one known Vermont record for Persius Duskywing, from an unknown location in 1983 by P.A. Opler (Grehan et al. 1995). There are no other details available.

The Vermont Butterfly Survey added 11 butterfly species to the Vermont checklist. Most of the new records were obtained from the southernmost region of Vermont where little collecting had been done historically. However, both the Hackberry and Tawny emperors were found in the northwestern region of Vermont where most historic collecting occurred. Because they were found only in a few floodplain forests within the Vermont range of Hackberry tree (Celtis occidentalis), the two species may have simply been previously missed rather than recently immigrated into Vermont. Either way, Vermont is on the northern edge of the range of both emperors and their host plant. Six of the new species are now included as Species of Greatest Conservation Need in Vermont, 7 have been assigned a conservation rank of S1 (most imperiled), and 2 are designated conservation status unknown (SU) until further targeted surveys are complete.

Since the VBS, observers have annually provided many butterfly records to our project in iNaturalist (https://www.inaturalist.org/projects/vermont-atlas-of-life) and eButterfly (https://www.e-butterfly.org). Four additional species have been added to the checklist since VBS. An Eastern Giant Swallowtail was first photographed in a garden in Addison on 30 July 2010 by A. Fisher. Several days later a sighting was reported from a garden just 10 miles north in Charlotte by H. Kaestner. This species is now well established in portions of Vermont. The first US record of Common Blue was reported by David Barrington on 5 Sept 2020 in Alburg, VT with additional records later in the month in nearby Saint Albans, VT. This species presumably arrived here from the well established population in nearby Quebec, Canada. On 15 June 2021 a presumably vagrant Cloudless Sulphur (Phoebis sennae) was photographed by Terri Armata and reported on a checklist to eButterfly.org (https://www.e-butterfly.org/ebapp/en/checklists/view/109860). On 30 June 30 2022 in the far southwest corner of Vermont Terri Armata photographed a Northern Oak Hairstreak (Satyrium favonius ontario) among the Banded Hairstreaks (Satyrium calanus) nectaring at Common Milkweed and shared it with eButterfly.org (https://www.e-butterfly.org/ebapp/en/checklists/view/117328). The Northern Oak Hairstreak lays its eggs predominantly on White Oak (Quercus alba) in the northern edge of its range, which is found in the valleys of Vermont. It likely lives covertly, hidden from the eyes of butterfly watchers, feeding (on galls and Hemiptera honeydew) and breeding high overhead in the leaves and branches of the forest canopy and may be present in more localities. On 5 October 2022 James McNamara photographed a European Peacock Butterfly (Aglais io) in a garden in Calais, Vermont and reported it the Vermont Atlas of Life on iNaturalist (https://www.inaturalist.org/observations/137682387) marking the first state record for this species. The latest discovery was a population of Bog Elfin (Callophrys lanoraieensis) discovered in NW Vermont by Bryan Pfeiffer on 19 May 2023 and reported to eButterfly.org as part of the Second Vermont Butterfly Atlas.

The Vermont Butterfly Checklist is now comprised of 117 species in 5 families (Family:no. species= Hesperiidae 37, Lycaenidae 26, Nymphalidae 44, Papilionidae 6, Pieridae 8). Nomenclature follows: Warren, A. D., K. J. Davis, E. M. Stangeland, J. P. Pelham, K. R. Willmott & N. V. Grishin (2023) Illustrated Lists of American Butterflies (North and South America) 23-VI-2023 https://www.butterfliesofamerica.com/index.html