Almost everyone can identify a brightly colored orange and black butterfly as the monarch. Birds can also identify this color scheme as nature’s way of saying, “I am toxic and taste bad.” Monarch butterflies, as caterpillars, eat the leaves of various milkweed plants, storing up toxins from the leaves in their bodies. It is these toxins that give them an unappealing taste to would-be predators. This is just part of the amazing life cycle of the monarch.
August is a fantastic time to watch adult monarch butterflies flitting from flower to flower. You might not realize that there are another 120 or so species of butterflies found in the state, but it is the monarch that captures our attention with their unparalleled migration. Monarch butterflies undertake a two-way migration to escape the cold weather in the fall and then return north in the spring. We know that the final destinations for millions of monarchs in the fall are the Central Mexican Highlands. There, they winter over in Oyamel fir trees at elevations between 7,800 and 12,000 feet, deep in the Sierra Madre Mountains. The final generation of monarch butterflies in the late summer or early fall can live up to eight months, allowing them to survive through the winter. In spring, monarchs leave the wintering grounds and head north. No monarch leaving Mexico makes it to Maine. As they head north, the butterflies lay eggs on milkweed and as the new caterpillars grow and eventually metamorphosize into butterflies, these individuals continue the trek. It takes four or five generations to reach New England.
If you want to see monarchs, head out to Scarborough Land Trust’s Fuller Farm, Libby River, or Blue Point Preserves. In Maine monarchs lay their eggs on four native species of milkweed — common, swamp, poke, and butterfly weed. If you look carefully on the leaves of common milkweed at any of these three locations, you might spot a black, white, and yellow-green striped caterpillar. A large caterpillar ready to form a chrysalis is almost two inches long. From egg to chrysalis takes about 18 days. It takes another one-to-two weeks before an adult butterfly emerges. Common milkweed is most common around the parking area at Fuller Farm, the marsh overlook at Blue Point Preserve and near the observation deck at Libby River Preserve. For their safety, please don’t disturb the caterpillars or adults. Watch from a distance and enjoy this natural cycle.
Monarch butterflies are still easily found in meadows and fields across Maine. However, the species has been declining for at least the last 25 years. The World Wildlife Fund monitors the populations in central Mexico. Population estimates are made by the number of acres the butterflies utilize while roosting in trees overnight. At one point the estimated acres were 45; today this number is down to 5.5 acres. The decline has been so dramatic that the International Union for the Conservation of Nature added the monarch to its red list of threatened species as endangered. The United States Fish and Wildlife Service currently lists the monarch as a candidate for listing under the Endangered Species Act. There are a host of reasons why the monarch has declined, but this story is for a future column in Nature Notes.
The Scarborough Land Trust has several projects to help monarchs and other pollinators. Working in cooperation with the Natural Resource Conservation Service (NRCS), we have identified two pollinator projects at Fuller Farm Preserve. Along the Maine Trail there is a small clearing. Last fall we seeded a variety of native wildflowers beneficial to pollinators. This year along a section of the Hayfield Trail, we planted 40 native shrubs and small trees. Each of these plants were selected for their appeal to pollinators and their blooming times. It will take a few years for the shrubs and trees to grow, forming a hedgerow attracting not only bees, butterflies, and other pollinators, but a variety of wildlife.
NRCS states on their website, “Three-fourths of the world’s flowering plants depend on pollinators to reproduce. Most fruit, vegetable seed crops and other plants that provide fiber, medicines and fuel are pollinated by animals.” Through their Environmental Quality Incentives Program (EQIP), they provide technical and financial assistance for farmers and private forest owners to improve pollinator habitat on their properties. We have a NRCS service office in Scarborough; contact them at (207) 883-0159, if you want to improve pollinator habitat. You can also reach out to Scarborough Land Trust and we can direct you to other resources available for helping monarchs and other pollinators.
For comments or questions, contact Andrew Mackie at amackie@scarboroughlandtrust.org
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