Butterflies Count

This Silver-Spotted Skipper was one of many butterfly species that were documented during a July count around Bryn Mawr. | Photo by Jen Britton

Volunteer efforts across the region keep track
of our fine fluttering friends

The flashy colors of butterflies are matched only by their names: red admirals, great spangled fritillaries, tiger swallowtails, painted ladies and summer azures. On July 10, 13 volunteers at the North American Butterfly Association (NABA)’s annual Fourth of July butterfly count spotted all these species in all their regalia. The volunteers, who identified 18 other species too, visited six sites in a 15-mile radius around Bryn Mawr, Pa., to document all the butterflies they could find. More than 400 teams (including one at the John Heinz National Wildlife Refuge) participated in NABA’s three seasonal counts to provide snapshots of butterfly populations.

Volunteers included butterfly enthusiasts and parents looking to connect their kids to nature. Butterfly volunteer Jan Clark-Levenson says that walking through fields and forests to see what flutters by is “a child-friendly sort of thing.” Claire Morgan, community garden and volunteer coordinator for the Schuylkill Center for Environmental Education—one of the stops for the Bryn Mawr team—says the butterfly census is an opportunity to engage non-scientists in important research. It is also a chance to promote butterfly-friendly practices. But if Philadelphians want to help, “the biggest thing they can do is plant native plants,” Morgan says. Natives not only offer flowers to adult butterflies but serve as hosts for their caterpillars.

Not far from Philadelphia, the Cape May Bird Observatory’s volunteer-run Monarch Monitoring Project (MMP)’s observations have highlighted the importance of host plants in supporting wild butterfly populations.

Migrating monarch butterflies, just like migrating birds, like to stay over land as much as possible. The butterflies heading south from the Northeast along the Atlantic Coast end up down the Cape May Peninsula; at the end of which, they make the jump to Delaware, all on their way to the mountains of central Mexico. MMP communications director Mark Garland estimates that a million or so monarchs fly over the Cape every fall.

“In peak days, it’s overwhelming—like orange confetti all over the place,” Garland says. There are too many to count directly, but from Sept. 1 to Oct. 31, the volunteers take a census, driving across Cape May Point. Twenty-one years of these counts have showed the monarch population of the Northeast to be pretty steady.

Elsewhere, monarch populations have been plummeting. Habitat destruction in Mexico and genetically modified organisms (GMOs) are leading culprits. Monarch caterpillars live and feed on milkweed, a plant that up until recently has thrived on the edges of crop fields throughout the agricultural heart of North America. Widespread spraying of glyphosate (the herbicide in Roundup), enabled by the rise of soybeans, corn and other “Roundup Ready” crops modified to be resistant to glyphosate, has wiped out the weeds on the margin, including milkweed.

This kind of agriculture is less common in our region and in New England and Eastern Canada. These are also densely gardened areas with plenty of flowers for adult monarchs to drink from and milkweed for caterpillars to grow on.

“We may have a lesson to give to the rest of the country. Maybe if every farmer has a butterfly garden, or every church or school has a garden with milkweed, perhaps this is a reversible trend,” Garland says.

Bernard Brown is an amateur field herper and bureaucrat. He writes about urban natural history and sustainable eating.