Insects and pollinators
Bringing a rare butterfly back to Fort Custer
At first glance, Fort Custer Training Center is a renowned place where soldiers train. Yet, tucked within its 7,500 acres, a quiet revolution in…
Reported by U.S. Fish and Wildlife Service · · 2 min read
At first glance, Fort Custer Training Center is a renowned place where soldiers train. Yet, tucked within its 7,500 acres, a quiet revolution in conservation is underway and a rare butterfly makes its return. We at the U.S. Fish and Wildlife Service have a remarkable partnership that highlights the conservation efforts on military lands. Fort Custer is believed to be the first U.S. military installation to reintroduce a federally listed species, the Mitchell’s satyr, previously lost from this area in Michigan.
Fragile survivors
Fort Custer has the perfect backdrop for this rare butterfly, a type of wetland called prairie fens. Prairie fens are wetlands fed by groundwater that bubbles up through limestone. The water is rich in minerals and low in nutrients, which creates a special home for plants like sedges and grasses to thrive. Mitchell's satyr caterpillars eat those sedges, and adults lay their eggs on the grasses. Without these plants, the butterfly’s future would be uncertain.
Once widespread across the midwest and east coast, the small brown butterfly with black eyespots ringed in yellow now survives in only a handful of spots. Its slow, low flight lasts just a few weeks each summer, making it easy to miss and even easier to lose. The vulnerability of the species underscores the importance of the conservation effort.
Protecting fragile species demands teamwork. This milestone becomes possible through a remarkable partnership among Michigan Army National Guard, Michigan State University, John Ball Zoo, Michigan Natural Features Inventory, Kalamazoo Nature Center and our agency through Ecological Services program and the Great Lakes Restoration Initiative. Each partner plays a vital role, combining expertise and resources to make the reintroduction possible.
Using the flexibilities in the Endangered Species Act, the National Guard feels confident moving forward with the project. Through a formal review process, the new Fort Custer butterfly population is intended as a temporary reserve population. That label means these butterflies can later help start or strengthen other Mitchell's satyr populations elsewhere, if needed. We also have a biological opinion that covers the base's current and future activities, both on and off the property. This means the National Guard does not need to seek new approval every time its mission changes. If the base ever needs to shift how it uses the land, the butterflies can move to a new location without putting the project or the base's training mission at risk.
As U.S. Fish and Wildlife Service Biologist Tameka Dandridge describes, “When about 300 Mitchell’s satyr butterflies are released, our persistence and hard work make all the difference in making this idea a reality.” Because of this cooperation, the number of butterflies released in Michigan have grown by about 58% in the last two years. Each release, each improvement in rearing methods, each prairie fen restored and every new research finding is a step toward ensuring this rare butterfly’s future.
The journey is slow, but every milestone brings hope. As Fort Custer Training Center continues its quiet revolution, the story of the Mitchell’s satyr butterfly stands as a testament to what can be achieved when conservation and stewardship go hand in hand.
Field guide: Mitchell's satyr (Neonympha mitchellii)
The story above is about bringing this butterfly back to Fort Custer. Here is what that story says about the animal itself, organized so you can tell it apart, check a sighting and compare it with look-alikes.
How to tell it apart, step by step
Start with the place
It lives in prairie fens: wetlands fed by groundwater that rises through limestone, with water rich in minerals and low in nutrients, where sedges and grasses grow. No fen, no Mitchell's satyr.
Check the season
The adults fly for only a few weeks each summer. Outside that window you will not see one.
Look at size and colour
It is a small brown butterfly. A large or brightly coloured butterfly is something else.
Find the eyespots
Black eyespots ringed in yellow are its mark. Only brown butterflies with eyespots are candidates.
Watch the flight
Slow and low over the vegetation. A fast, high flier is not it.
Then step back
It is a rare, federally listed species. Photograph from a distance, note where and when, and do not chase or handle it.
Worked example
You are walking beside a wet, open meadow in Michigan in summer. A small brown butterfly drifts low over the sedges, flying slowly, and when it lands you see dark eyespots with a yellow ring. Place, season, size, eyespots and flight all match, so this is worth documenting with a photo, the exact spot and the date. It still is not an identification: other brown butterflies share wet meadows, and only an expert can confirm it.
Could it have been a Mitchell's satyr?
Answer what you saw. Each answer is compared with what the story says about the species. Leave blank what you did not notice.
Your result
Answer at least three questions
With fewer answers there is nothing to compare yet.
Compare it with look-alikes
Narrow the list by where you saw the butterfly and by its eyespots. The table shows which brown butterflies are still candidates.
4 of 4 species still match
Mitchell's satyr Neonympha mitchellii
- Habitat
- Prairie fens: groundwater-fed wetlands with sedges and grasses
- Looks
- Small brown butterfly; slow, low flight
- Eyespots
- Black eyespots ringed in yellow, in a row
- Protection
- Federally listed under the U.S. Endangered Species Act
- Check at
- fws.gov
Eyed brown Satyrodes eurydice
- Habitat
- Wet sedge meadows and marshes
- Looks
- Brown butterfly of similar build
- Eyespots
- A row of eyespots on the underside
- Protection
- Not covered here
- Check at
- butterfliesandmoths.org
Little wood-satyr Megisto cymela
- Habitat
- Woodland and shrubby edges
- Looks
- Brown, found in shade
- Eyespots
- Two large eyespots on each wing
- Protection
- Not covered here
- Check at
- butterfliesandmoths.org
Common wood-nymph Cercyonis pegala
- Habitat
- Open fields, meadows and woodland edges
- Looks
- Larger and darker brown
- Eyespots
- Two large eyespots on the forewing, often on a pale yellow patch
- Protection
- Not covered here
- Check at
- butterfliesandmoths.org
The Mitchell's satyr row comes from the story above. The other three are general field-guide knowledge, included only to show what can be confused; the link on each row goes to that species' page in Butterflies and Moths of North America, where you can check the description, and a regional field guide is still worth consulting. Protection status for them is not covered here.
Mitchell's satyr: questions and answers
What does Mitchell's satyr look like?
A small brown butterfly with black eyespots ringed in yellow.
Is it a butterfly or a moth?
A butterfly. The U.S. Fish and Wildlife Service calls it a rare butterfly. In Spanish, "mariposa" covers both butterflies and moths, which is why the name sometimes appears as "mariposa sátiro de Mitchell".
Where does it live?
In prairie fens: wetlands fed by groundwater that bubbles up through limestone. The water is rich in minerals and low in nutrients, and sedges and grasses thrive there.
What does it eat?
The caterpillars eat sedges. Adults lay their eggs on grasses, so both kinds of plant are needed.
When can it be seen?
The adults fly slowly and low for only a few weeks each summer.
Why is it rare?
It was once widespread across the Midwest and the East Coast of the United States and now survives in only a handful of spots. It depends on a narrow kind of wetland and its plants, and it is a federally listed species.
What is happening at Fort Custer?
Fort Custer Training Center in Michigan is believed to be the first U.S. military installation to reintroduce a federally listed species. The butterfly had been lost from the area. The population is meant as a temporary reserve that could later help start or strengthen other populations.
What should I do if I think I saw one?
Photograph it from a distance, note the place and date, and do not catch or handle it. Send the details to your state wildlife agency or to the U.S. Fish and Wildlife Service.
Facts about the species: U.S. Fish and Wildlife Service: fws.gov
