The early season here in the Piedmont around DC is mirrored in an early flight of some of the specialties offered by Maryland’s Green Ridge State Forest (GRSF) in Allegany County. I took advantage of a light schedule at work today to take leave and head out to this prime early-season lep locale.
Principal among these specialties is the the state’s most robust colony of Olympia Marble, which once was very common across the shale barren habitats of Allegany and Washington counties. Today, however, the population of these little pierids has dwindled to precariously small, so it’s always a treat to see these butterflies on the wing in their remaining habitat. The species has suffered most from degradation of its habitat — Marbles require open shale barrens that supply the early spring cresses that provide both larval food and adult nectar, and because the forest is managed using fire suppression, these barrens are rapidly growing up in trees and shrubs. Gypsy Moth spraying has also taken its toll, as it almost certainly wiped out another species that used to fly in the same habitat, Appalachian Grizzled Skipper.
Usually we look for these around the middle of April through early May; however, I’ve been thinking for some time now that we’re only seeing the end of the flight when we arrive that late. In other areas where it flies with Falcate Orangetip (as it does in Green Ridge), it usually emerges earlier. Yet when we’ve visited the colony of Marbles, it’s taken much chasing and netting to weed out the female Falcates and Cabbage (Small) Whites from the similarly sized and similar acting Marbles.
Today, however, the Olympia Marbles had their patch of shale scree all to themselves — Falcate Orangetips are just now emerging in GRSF, and only the fiery-orange-tipped males are on the wing, so one can tell them apart easily. Ditto with Cabbage Whites; I saw only a handful all day and none in the Marble habitat. Olympia Marbles, by constrast, are already in full flight: I saw a dozen or more (hard to be sure without mark/recapture, as they keep popping in and out of the neighboring woods), including one period where I had four in view at once. I think this isn’t just a phenomenon of the early spring season we’re experiencing; I think we butterfly folks don’t get out in the field early enough.Also on the wing in GRSF today, in addition to the Falcate Orangetips and Cabbage Whites, were early Sleepy Duskywings, an assortment of lucia and neglecta azures, Silvery Blue, and the expected Mourning Cloaks and an Eastern Comma. Sharing the same shale barren with the Olympia Marbles was another insect of conservation concern in Maryland, Cow Path Tiger Beetle, Cicindela purpurea. This fiesty little beetle occurs in a thriving patch less than an acre in size at the same place the Marbles fly; I haven’t yet seen their larval burrows but believe I’ll be headed back to study these better a little later in the season.