By Alyssa Kobylarek, MNA intern
The Mitchell’s satyr butterfly is considered one of the world’s rarest butterflies. Historically, it was found in New Jersey, Ohio, Michigan, Indiana and Maryland. Today, it is only found in 19 sites throughout Michigan and Indiana.
The Mitchell’s satyr butterfly is a dark brown, medium sized butterfly with a wingspan ranging from 1.5 to 1.75 inches. The undersides of their wings contain orange bands and a row of four to five black eyespots surrounded by yellow rings. The three spots in the center are always the largest.
In July, females lay their tiny eggs close to ground on young leaves of plants, usually on the undersides of the leaves or on the stems. The eggs hatch within seven to eleven days. The caterpillar feeds on sedges and hibernates under the snow during the winter months to later emerge and resume its development and form a cocoon. In late June and July, the butterfly emerges to live its adult life for about two weeks.
These butterflies are the most geographically restricted species of eastern butterfly. This is because they require a special type of wetland habitat to survive. These wetlands are only found in prairie fens, which globally rare and very vulnerable because they are only found in parts of the midwest that were carved by glaciers. Prairie fens are one of the most biologically diverse ecosystems in Michigan. They are low-nutrient grassy wetlands with peat soils that have a basic pH balance. They have a unique diversity of plants and animals specific to the fens due to their soil and alkaline groundwater that feeds into it from seeps and springs. Tamarack trees, poison sumac, sedges and a variety of wildflowers call the prairie fens their home.
This species was put on the endangered species list on June 25, 1991 for a number of reasons, but the main reason was loss of habitat and land modification. Many of the fens the butterflies are native to have been altered for agriculture and land development. This has also led to invasive species of plants that make the land unsuitable for the butterflies. Natural processes like wildfires, changes in water levels and flooding from beavers have been eliminated from the fens. A Federal Recovery Plan has been completed which guides conservation efforts for the butterfly and its habitat. The Department of Natural Resources also received a grant in 2006 that provides a framework for managing prairie fens for the butterflies.
The Michigan Nature Association currently has 14 sanctuaries that contain prairie fens. MNA began working to conserve Michigan’s prairie fens in 1961 and still continues efforts today in order to protect these habitats and the wildlife that depend on them. MNA’s efforts to benefit the fen and the butterflies include prescribed burns to help restore the habitat and the removal of invasive plants. To get involved, visit www.michigannature.org.