Butterflies at Rockfish Valley Foundation (RVF) (Updated Nov 2020)
Since 1993, the North American Butterfly Association http://www.naba.org/ has sponsored annual butterfly counts throughout the U.S., Canada, and Mexico. These counts were modeled on the annual Christmas Bird Counts that were first established in 1900 by the National Audubon Society https://www.audubon.org/conservation/history-christmas-bird-count Each count is conducted within a 15-mile diameter circle, and, in 2000, an official count circle was created in Nelson County. The geographic center of the Nelson circle is near the end of Davis Creek, which means that a large portion of Nelson County is included within the circle. The boundaries of the circle extend from Reed’s Gap on the Blue Ridge Parkway to the Dutch Creek area north of Shipman.
Butterflies are “cold blooded,” (ectothermic), which means they have no way of keeping warm when outside temperatures are too low. The ideal temperature for a good day of butterflying in Nelson County is in the 80s, with a slight to no breeze, and sunny to partly cloudy. When the temperature falls into the 50s, butterflies in central Virginia hunker down and don’t fly much. They also tend to shut down when temperatures soar into the 100s. In order to observe the most butterflies, the Nelson Count is usually held on a day in July.
In 2005, RVF opened its first trail system to the public. That same year, the Foundation’s trails and meadows were added to the list of locations for participants to visit on the Nelson Butterfly Count. The result of adding RVF as a counting location added greatly to the count results, and the trail system became one of the most popular and well-liked stops on the Count Day by participants. More than 40 species have been observed on the RVF trail system during official Count Days, with additional species observed there during other times of the year.
RVF is one of the best places in Nelson County to observe the Gray Hairstreak, Strymon melinus. Although it is one of the most widespread of the many species of hairstreaks in North America, it is not real common in Nelson County. RVF is one of the few places in the county where it can be reliably found during July. Look for it in the parking lot by the Rockfish River. It is a small gray butterfly, less than an inch in size, that perches on low grasses with its wings closed. One, or sometimes two, bright orange spots on the tip of its wing serve as good identifying features. The west trail along the Rockfish River at RVF apparently offers a micro-environment conducive to this species, as it is sometimes can be seen in numbers during the Count Day. Its larvae (called caterpillars) feed on a large variety of plants.
Another species of note that can be see at RVF is the American Copper, Lycaena hyllus. This butterfly is mostly found in states in the northeast and Midwest, and it is quite rare in central Virginia. It is about the size of the Gray Hairstreak, and its forewing is a rich golden color while its hindwing is grey with black spots. It is generally seen perched within a few feet of the ground.
Although moths are not an official part of the butterfly count, the current leader of the Nelson Butterfly Count keeps a record of any moths observed on the count day. A number of day-flying moths are always seen, including the striking Black-bordered Lemon, Marimatha nigrofimbria. This moth is fairly common in the area, but it has never been observed on Count Day at any location other than RVF. At little more than a half-inch is size, it is actually easy to spot due to its brilliant yellow color. It perches with its wings open, and there is a black border on the trailing edge of its wings. The RVF meadows appear to be good habitat for this moth. Its larvae feed on Morning Glories and Crabgrass.
RVF trails and meadows are great places to look for butterflies and other insects. A number of good guide books are available to help you Identify butterflies, and if you are thinking of buying a new pair of binoculars, consider purchasing close-focus binoculars. This type of binoculars allows you to focus on objects that are only a few feet away, but they can also be used for birding.
Even if you don’t have close-focus binoculars or a butterfly guide book, one species you most certainly can see and easily identify at RVF is the Eastern Tiger Swallowtail, Papilio glaucus. With a wingspan that can measure up to five and a half inches, you can’t miss this big, bold butterfly. It is yellow with black “tiger” stripes on the leading edge of its wings. (Note: some of the females come in a dark phase that is difficult to distinguish from other dark swallowtails.) This is the state insect for Virginia, and it is found throughout the state. At RVF, don’t be surprised if one of these beauties comes floating past you on a trail. They can be identified even as they fly away! Plus, they can be seen nearly year-round – in spring, summer, and fall … and once in a while, one can be seen on a warm January day!