Earth Journal by Gary Pendleton

Buckeye Butterfly

Perhaps the little buckeye butterfly is not as striking as some other species. It is fairly small, and its color is not bright or bold. It is mostly an earthy mix of orangey-brown and tan. Other butterflies will catch your eye with their bright colors as they gently float around the garden, lighting on the tall flowers planted there. Not so the buckeye; it flits more than floats and tends to land closer to the ground, where it is less likely to be noticed by you.

Though buckeyes lack the bright color and size of some of their more glamorous kin, they make up for any shortcomings with very interesting markings called eye spots. Eye spots are simply round markings on the wings. It’s believed that eye spots give pause to a predator looking for a meal because they make the defenseless insect look like some larger and more formidable creature.

The cleverly adapted buckeye appears here in the Mid-Atlantic and all over North America from the Deep South to the far north throughout the summer. Though they are capable of venturing as far north as the Canadian tundra, they need to migrate south before cold weather to survive and procreate. Along the East Coast in autumn, impressive migrations move south, according to lepidopterist Robert Michael Pyle, author of the Audubon Guide to Butterflies. The mass migration of the buckeye is said to rival that of the more famous monarch.

But is it a true migration? Mark Garland, senior naturalist at the Cape May bird observatory, isn’t so sure. He consulted a few recently written authoritative texts to summarize and interpret the current understanding of buckeye travels for us.

The migration starts in the south, around the Gulf Coast in early summer. As the weather warms, successive generations of buckeyes move northward. By late summer, the descendants of the spring-born buckeyes, a few generations removed, have arrived in the far north. As summer closes, many of the buckeyes move south, concentrating in coastal areas as they travel.

The winter range of the buckeye begins along the North Carolina coast and stretches south and west from Florida to Arizona and Mexico. In those warmer climes, the butterflies can lay eggs with a good chance of surviving the winter.

Why the coastal concentration? The Atlantic shoreline is angled so that the Maine coast is well to the east of Florida.
Therefore, many of the south-traveling buckeyes reach coastal areas at some point along the way. Steady northwest winds that accompany cold fronts can push the butterflies to the east, so cold fronts have the potential to increase concentrations along the coast. Cape May is a famous choke-point for migrating birds and butterflies. But areas along the Western Shore of Chesapeake Bay are also, at least in theory, places that have potential for concentration.