To most people, butterfly migration is best illustrated by the iconic monarch butterfly (Danaus plexippus). It is well known for its annual fall migration from the northern United States to its overwintering grounds in Mexico and returning northwards each spring. But while the monarch gets most of the attention did you know that there are other butterfly species that also migrate? Their journeys are less noticed and not as long. These butterfly species are also heading to frost-free areas of their range. They cannot survive sustained freezing temperatures at any stage of their lifecycle.
Although most of Georgia’s 176 species of butterflies do not migrate, here are some that journey south each winter. This list includes the common buckeye (Junonia coenia), painted lady (Vanessa cardui), American lady (Vanessa virginiensis), cloudless sulphur (Phoebis sennae), question mark (Polygonia interrogationis), fiery skipper (Hylephila phyleus), clouded skipper (Lerema accius), long-tailed skipper (Urbanus proteus), ocola skipper (Panoquina ocola), long-tailed skipper (Urbanus proteus), sachem (Atalopedes campestris), mourning cloak (Nymphalis antiopa), red admiral (Vanessa atalanta), gulf fritillary (Agraulis vanillae), and the Little yellow (Pyrisitia lisa).
Georgia’s other butterflies are adapted to overwinter through a variety of strategies, depending on the species. Some will overwinter as a caterpillar, such as the tawny emperor (Asterocampa clyton), viceroy (Limenitis archippus), and red-spotted purple (Limenitis arthemis). They create a hibernacula or nest out of leaves and wait until spring to emerge. When the warmer temperatures arrive, they emerge and begin eating and growing again. Others, like the Eastern tiger swallowtail (Papilio glaucus), Georgia’s state butterfly, will spend the winter as a chrysalis and emerge as an adult in the spring.
Why do butterflies migrate? Like all insects, butterflies are cold-blooded. This means that their body temperature is regulated by the external temperature of the air and surrounding conditions. As winter approaches, many butterflies must move southwards to overwinter in a warmer climate. Additionally, they also migrate for their food sources.
But where do they go? This is a question that, for the most part, is still unknown to scientists. It is difficult to track butterflies because there must be a method of tagging and relocating the tagged butterflies. The Monarch butterfly, being the most studied, has been found to travel to three different locations. The largest eastern population travels mainly to central Mexico to a fir-pine forest. The eastern population that is along the Atlantic Ocean travels south into Florida. After arriving in Florida, it is unknown if they travel further, die, or have an undiscovered overwintering site. The western populations of Monarchs, west of the Rocky Mountains, overwinter in California on Pine and Eucalyptus trees. There is also a non-migratory population of Monarchs that live in southern Florida. They are active throughout the winter months.
Many butterflies that do migrate usually have a one-way trip. They will lay eggs and produce new generations. Come spring, their offspring will head back north, repopulating Northern states and even parts of Canada. Monarchs are the exception. The Monarch generation that makes the southward journey in the fall begins the northward journey the following spring, laying eggs. The following generations make it to the locations farther north.
By planting specific perennials in your garden, you can create a waystation to rest and refuel for part of this butterfly migration journey south. Include in your garden fall blooming nectar plants to round out the growing season. These plants include goldenrod (Solidago spp.), aster (Aster spp.), swamp sunflower (Helianthus angustifolius), blazing star (Liatris spp.), salvia (Salvia spp.), joe-pye weed (Eupatorium purpureum), ironweed (Vernonia fasciculata), and pineapple sage (Salvia elegans).
So, what are you waiting for? Grab your favorite butterfly field guide, binoculars, camera, and cell phone, head outdoors and follow this great migration. What a terrific time of year to observe them on their trek against the backdrop of blue skies! Be sure to upload your sightings to iNaturalists. Every observation can contribute to biodiversity science, from the rarest butterfly to the most common backyard weed. All you have to do is observe.