As part of an Elizabeth Islands Survey aimed at documenting species as representative of the biodiversity present on the island chain, the Lloyd Center set ultraviolet light traps on two nights at Cuttyhunk in late summer (August 26) and early fall (October 7), a timeframe coinciding with flight periods for various species. With the generosity of the Cuttyhunk Ferry Company, with which we partner for seal watches each year, we were transported to the island to set traps and returned the following mornings to pick up traps and sort the catch. While on the island, there were many hours to roam in search of butterflies, caterpillars, bird life, and evidence of the Water-willow Stem Borer (Papaipema sulphurata), a listed moth endemic to Southeastern Massachusetts and found in coastal plain wetlands (NHESP 2007), and of special interest to Lepidopterists.
Between 1988 and 2015, there were 24 moth species documented on Cuttyhunk Island. From these two trips in 2016, 55 species were documented, 51 of which were new records! One species is listed in the state of Massachusetts. Other Lepidoptera discovered included one caterpillar species of the Virginia Tiger Moth (aka the “Yellow Bear”) and various butterflies. The Wood Nymph was by far the most abundant butterfly encountered with large numbers seen on the August trip, when fritillaries and swallowtails were also seen. On both trips American Copper, Monarchs, and various sulfurs were also present.
For bird life, the August trip featured migrant shorebirds and seabirds including Black-bellied Plover, Semipalmated Plover, Willet, Yellowlegs spp., both Least and Common Terns, and American Oystercatchers, all gathered at West End Pond. Waders at the pond included the familiar Great Blue Heron and Great Egret. Large numbers of Double-crested Cormorants were situated in line with the inlet, surely waiting for the next influx of fish. For raptors, both Osprey and the Northern Harrier were seen in flight. For songbirds, Tree Swallows, an early migrant, were a common sight. On this trip some reptiles also ventured onto the network of wide dirt pathways that crisscross the island, including a Painted Turtle and curiously large numbers of Garter Snakes!
In October, songbird species were a feature attraction, and the date coincided with movements of many fall migrants. A significant wave had come through, and a gorgeous 70-degree day made for great bird watching conditions. Vesper Sparrow (and other sparrows), Juncos, Yellowthroat, and Carolina Wren were a few species encountered. A movement of Palm Warblers, Yellow-rumped Warblers, and Golden-crowned Kinglets had clearly occurred, as numbers were high for these species. The bird sighting of the season may have been a Bobolink in non-breeding plumage, lingering in the reeds and low shrubbery bordering the pond, surely a bird passing through in migration that’s indicative of the avian diversity present on the island.
In addition to all the biodiversity, this small project offered the experience of the island’s hills, woodlands, and shorelines when the busy visitation season ends, and the best sunsets one could ask for. For the curious eye, Cuttyhunk Island is a natural wonder!