5 things to know about the migrating Monarch Butterflies

By New Jersey Audubon September 15, 2022

Written by Adehl Schwaderer, Tom Reed, and Jack McDonough

Pictures by Michelle Giorla

Monarch Butterfly being checked before tagging. This is a male. — Monarch butterfly being checked to see if it’s a male or female. This is a male.

Do monarchs migrate?

Yes, monarch butterflies do migrate!

Monarchs undergo the longest migration of any butterfly in North America and make biannual treks between central Mexico and southern Canada. In the fall, one generation of monarchs flies over 3,000 miles to the mountains of Sierra Chincua west of Mexico City. In the United States, Monarchs are part of only 6% of Lepidoptera—an order of insects that includes butterflies and moths—that do not have the physiological capability of overwintering as caterpillars like many other butterfly species. For this reason, monarchs are considered a tropical butterfly and must migrate to a warmer climate for the winter. For them, the closest ideal climate happens to be in Mexico.

Monarchs migrate throughout North America to take advantage of ample amounts of milkweed, the host plant that facilitates each successive generation. Most western populations of monarchs do the same, but in contrast to their eastern counterparts, they overwinter along the coasts of Santa Barbara, the East Bay of San Francisco, Monterey, and other similar areas in central and southwestern California.

Monarch butterfly in Cape May Point State Park

Where and when can I see migrating monarchs in Cape May?

Cape May offers many places to see monarchs. The dunes in and near Cape May Point State Park are a likely spot to see monarchs feeding on Seaside Goldenrod and other native plants. Cape May Point offers many terrific gardens, such as the Pavilion Circle, that promote the visitation of all our migrant visitors—including people. Additionally, The Nature Conservancy’s Garrett Family Preserve hosts expansive native wildflower meadows that serve as great stopover habitat for a variety of butterfly species, and be sure to check out the brand new monarch sculpture at the parking area!

Later in autumn, particularly during October when it starts getting much cooler at night, monarchs communally roost by the hundreds in pines around the dune crossings of Cape May Point. When monarchs migrate to Mexico, they go up to some 11-12,000ft above sea level in the Sierra Chincua Mountains where some of the only trees that grow at that elevation are conifers. This behavior leads us to believe that monarchs favor roosting on pine trees and other conifers during migration.

Visit the Cape May Monarch Monitoring Project’s Facebook page, or Instagram @capemaymonarchs for nightly updates on publicly accessible roosts.

Monarch Butterfly Cape May Point State Park — Monarch butterfly Cape May Point State Park

What threats do monarch populations face?

Monarchs suffer from countless factors of anthropogenic activity, parasites such as the acclaimed OE (Ophryocystis elektroscirrha), and severe weather patterns—especially during migration. Declines in monarch populations also have lots to do with more typical threats such as major habitat loss (including overwintering sites in Mexico and California), pesticide use in agricultural farms and backyard gardens, mowing of natural meadows and roadsides where their milkweed grows, and a lack of conservation support from policy makers.

Climate change has also become a big issue for migrating monarchs. Monarchs are multigenerational, so for those fourth- and fifth-generation monarchs that begin their life cycles late in August or early September, their job as soon as they emerge from the chrysalis is to go straight to Mexico. At that point they are in a strong, pristine condition to make the trek to Mexico. If it stays warmer longer into the season, these migratory monarchs linger longer—perhaps even attempt to breed—and by the time they leave, they are in much more worn condition and are not as physically fit to make that journey. This can lead to a higher mortality rate, with fewer and fewer monarchs actually making it to Mexico.

Pointing to a monarch egg under the leaf.

How can I help the monarch?

The most important way we can help monarch is by poviding feeding and egg-laying habitat. Monarch caterpillars rely on milkweed to eat as they grow. In fact, female monarchs will only lay their eggs on milkweed. Planting wildflower gardens and backyard habitats can be a great way to encourage others to do the same and promote wildlife within human environments. Be sure to check out your local nurseries to purchase plants that are native to your area!

Also, buy organic produce and foods that don’t use pesticides and herbicides, especially on farmland areas where native milkweed often grows.

Talking about the Monarch Monitoring Project at The Nature Center of Cape May

How can I learn more about the monarch?

When visiting Cape May, there are several places you can visit to learn more about the monarch. First, be sure to stop by the Cape May Bird Observatory’s Northwood Center in Cape May Point to check out their live monarch display and pick up free resources about how you can help native butterflies. Next, visit the Nature Center of Cape May to walk their nature trail lined with native pollinator-friendly plants, and stop inside to see another monarch display and other fun features.

Every week throughout the fall, New Jersey Audubon’s Monarch Monitoring Project (MMP) hosts two different programs to educate visitors about the monarch. The first is the MMP Drop-in, which takes place at Triangle Park in Cape May Point. This informal program allows visitors to ask questions of the Monarch Field Naturalists and learn how to tend gardens that best support butterflies. The second program is Monarch Tagging Demos at The Nature Center of Cape May. After a short presentation about the history of the project and details of monarch migration, visitors watch as small tags are affixed to monarchs to track their migration!