Nature Notes: Monarch Madness

by Anna Foster, Director of Programming

A symbol of summer, monarch butterflies are widely recognized for their bright orange, black, and white spotted wings. Their scientific name, Danaus plexippus, translates to “sleepy transformation” in Greek, referring to their incredible ability to metamorphosize. From their larval stage, they form a chrysalis, spending two weeks metamorphizing into an adult butterfly. The tiny, delicate monarch butterfly not only transforms itself but takes on an amazing feat each year. Monarchs migrate between 1,200 and 2,800 miles to the mountains of central Mexico, where they overwinter. There, they gather in the millions to rest, with tens of thousands of monarchs resting on a single tree. In the spring, they make the journey back north, making it to the southern United States to lay eggs. These eggs are the first generation of the next year’s monarch population, slowly making their way northward.

Butterfly Life Cycle by US Forest Service (left), Monarchs clustering on a tree in the El Rosario Sanctuary, Mexico by Sue Hill (right).

For many people, including myself, monarchs hold more meaning than the symbol of species conservation. I can recall finding monarch butterflies in my grandmother’s field as a little girl. We would collect the small caterpillars, put them in an enclosure made with wood and mesh, and pick milkweed leaves for them until they were big enough to form a chrysalis. Caring for monarchs taught me about the need for native wildflowers (like milkweed) for butterflies and other pollinators. It also taught me patience – a required skill for monarch rearing and a skill not often developed in 3-year-old children. Now when I see monarch butterflies, I think of my grandmother. Many others had similar experiences as children, whether it be with a parent, grandparent, or teacher in an elementary classroom. We’re also lucky to be able to rear monarchs here at the Ridges, sharing the lifecycle of the butterflies with children and families who visit the Nature Center!

While monarch rearing is a contribution to the conservation of the species, staff at the Ridges also contribute to the yearly data on monarch butterfly populations during their migration south, through the southern United States, and down to central Mexico. Every year, the Ridges receives tags from the non-profit organization Monarch Watch, which we apply to the migrating monarch butterflies before they are released at the end of August. Scientists in the southern United States and in Mexico collect monarchs with these tags and record them. This way, we can identify monarchs that have migrated from Door County all the way down to their winter habitat! This data also contributes to data sets that tell us about monarch migration patterns and population sizes from year to year.

A tag diagram by monarchwatch.org (left), Ridges Monarch being tagged and released by Anna Foster (right).

From what I’ve been able to observe during my time spent outside, monarchs are back this summer in what appear to be much greater numbers! Last year, we struggled to find monarch caterpillars on the milkweed within the Ridges. I also noticed significantly fewer monarch butterflies the previous year (2021). However, this year, I regularly see multiple monarchs fluttering around the front gardens of the Nature Center on my way in to work. Research has shown that single weather events can have a huge impact on monarch populations from year to year, particularly, deviations from the mean temperature and precipitation (Monarch Watch Blog, 2023). For example, drought results in a shortage of milkweed, on which monarchs rely throughout their lifecycle. A late spring snowstorm could also impact monarchs migrating to northeastern states.

Monarch Migration Map (USGS National Atlas)

Based on 2023 data from monarchwatch.org, the migrating populations are expected to remain similar to populations in the last decade. However, the season isn’t over. There are still plenty of factors at play. In a recent newsletter from the organization, Jim Lovett stated, “The size of that generation [migrating south] will largely depend on the temperatures, nectar availability and quality and abundance of the milkweeds in the breeding areas north of 40N” (Monarch Watch July 2023 Newsletter). It’s important to collect data on monarch populations each year to learn more about population trends. Monarch butterflies have been in decline for many years, with statistics varying from 22% decline to 90% decline (IUCN, Monarch Watch). The large variation in percentages is likely due to the lack of data on monarch butterflies. In 2022, monarchs were added to the IUCN’s Red List as an Endangered species. Collecting data will help us determine how to best conserve the species and other important pollinators.

There are so many ways to protect monarch butterflies and other native pollinators! Come learn about what you can do at our annual Monarch Madness event on August 26^th. Ridges staff will be in the Nature Center to answer questions and teach visitors about monarch caterpillars and butterflies. We’re starting the day with a monarch-themed Story Hour at 10:00am outside the Nature Center for young children and their families. After Story Hour, we’ll be hosting a monarch tagging event from 11:00am-1:00pm. During the event, visitors can sponsor a monarch butterfly for $5. This includes tagging and releasing the butterfly. We do have a limited number of monarch butterflies available to tag, so plan to get to the Center promptly at 11:00am if you’d like to sponsor a monarch. In addition, we will be offering tags for $5 each to take home and tag monarch butterflies in your community!