Just as fall color is brought on by cooler weather and shorter days, the Eastern Monarch butterfly’s migration is also driven by seasonal changes. Thus, the time of year has arrived for folks along the east coast to look for signs of Monarch butterflies making their way southward. Depending on your location, the fall migration extends from August to November.
But, just where exactly are they going? Worldwide, no other butterflies migrate like the Monarchs of North America. Monarchs travel much farther than all other tropical butterflies – up to three thousand miles. They are also the only butterflies to make such a long, two-way migration every year. They fly in large masses to the same winter roosts, often to the exact same trees. Unlike birds and whales, which also migrate, monarchs only make the round-trip once; it is their children’s grandchildren that return south the following fall.
Monarchs east of the Rocky Mountains, such as those we see each year, are on their way to the Sierra Madre of Mexico to overwinter on the oyamel (or sacred fir) trees of the area. The fir trees provide the perfect habitat, combined with the area’s optimal temperatures and humidity, to ensure that the butterflies survive the winter.
How can you help them with their journey? Monarchs descend from their sky high migration path of up to 10,000 feet looking for food resources. To increase the chances of seeing this phenomenon and to assist the butterflies, plant a fall migration garden.
Joe Pye weed (Eutrochium purpureum), goldenrod (Solidago spp.) and Mexican sunflower (Tithonia rotundifolia) are all proven Monarch attractors. Several fall-blooming native aster plants (Aster spp.) are perfect for these butterflies as well. Any caterpillars you see now will most likely be pupating very soon and should migrate. When migrating, most monarchs will save energy and instead of mating or laying eggs, will focus on drinking nectar to fuel up for their journey.
To follow the Monarch migration and to report your butterfly sightings, visit Journey North at journeynorth.org/monarchs. This organization has tabulated the reports of citizen-scientists for many years and is a great resource for school groups. Monarch Watch, accessible at monarchwatch.org, also provides online information about these insects and their habitat needs.
The Monarch’s migration is one of nature’s most astounding events. With the change in weather, millions of infant butterflies that have never been to their ancestral breeding grounds are beginning their rigorous journey to the very trees that prior generations roosted in before they were born. I’ve seen several gliding through north Georgia, but they can be easy to miss if you aren’t looking.
If you do happen to miss the fall Monarch migration, spend time getting your garden ready for the Monarchs’ return in the spring. UGA Extension has a wealth of information on how to create pollinator habitats!
