With some misgivings concerning the weather, eight teams of volunteers visited gardens, plant nurseries and natural habitats for the Loudoun Wildlife Conservancy’s 22nd annual butterfly count August 4. We counted an astounding number of Monarchs – 289 – more than triple the number seen last year! I like to think that gardeners’ willingness to plant milkweed and tolerate the damage done by the caterpillars has some bearing on this. The Monarch caterpillars you see now are of the generation that will head south to winter in Mexico or Florida.
Another migrant we found is the goofy looking American Snout. It is not as large and showy as the renowned Monarch but its migration occasionally makes the news in Texas. We don’t see them in the count every year. I felt positively honored when one graced my shirt as I strolled along. The snout caterpillar feeds on hackberry (Celtis), a fairly common tree in Loudoun County.
A butterfly completely missing from our count this year is the Pipevine Swallowtail. This is a tropical species that can migrate as far north as southern Michigan and a relatively large number were seen in last year’s count. To be sure, we don’t see them every year. It could be that our harsh dry winter set them back. As we know, making the host plant available and allowing the caterpillars to feed unmolested is a key to attracting butterflies. The Pipevine Swallowtail is named for its host plant, pipevine (Aristolochia). Virginia Snakeroot is in this genus, among others. An interesting fact is that within the Pipevine Swallowtail’s range you will find a number of mimics: the black form of the female Eastern Tiger Swallowtail, the Spicebush Swallowtail, the Black Swallowtail, the Red Spotted Purple (not a swallowtail) and the female Diana (also, not a swallowtail).
The volunteers, many completely new to butterfly watching, did an outstanding job. We tallied 3,221 individual butterflies in 49 species. Thank you for your help!
Gray Hairstreak, Zebulon Skipper and Least Skipper photos by Michael Myers. Red Admiral photo by Bryan Henson.