Scientific name: Erynnis martialis
Cover photo credit: Deanna Dodgson
“Endangered” means the species lives in the wild in Ontario but is facing imminent extinction or extirpation.
Date added to the Species at Risk in Ontario List
June 27, 2014
Read the report (PDF)
What it looks like
The mottled duskywing is a medium-sized butterfly in the skipper family with a wingspan of 25-42 mm. It is dark grey with yellow-brown spots on its hind wings that give the species its mottled appearance and its name. The wings of freshly emerged adults have a purplish iridescence that fades with age.
Where it lives
While many butterflies thrive in lush meadows, the mottled duskywing tends to live in dry habitats with sparse vegetation. These include open barrens, sandy patches among woodlands, and alvars. (Alvars are areas of limestone with shallow soil and sparse vegetation of grasses, shrubs, and wildflowers.)
In Ontario, the mottled duskywing will only deposit their eggs on two closely-related plants: New Jersey tea and prairie redroot.
Larvae build silk leaf-nests and spend the winter as mature larvae, emerging as adults between mid-May and late June. In southwestern Ontario, a second brood matures in early July and takes flight between mid-July and late August.
Where it’s been found in Ontario
Scattered populations of this butterfly occur throughout southern Ontario. They have recently been documented in the Burlington and Oakville areas, and in Marmora (east of Peterborough).
Some documented sites are within protected areas, including provincial parks and land set aside for conservation.
What threatens it
The main threat to the mottled duskywing is the destruction of its habitat by human development. Almost all current sites where this butterfly is found are facing one or several threats, including urban development, natural changes to its habitat, spraying for LDD moth control, flooding, and changes to habitat from the planting of jack pine.
Action we are taking
Endangered Species and their general habitat are automatically protected.
Government response statement
A government response statement outlines the actions the government intends to take or support to help recover the species.
Read the government response statement (March 23, 2016)
Review of progress
A review of progress made toward protecting and recovering a species is required no later than the time specified in the species’ government response statement, or not later than five years after the government response statement is published if no time is specified.
Read the report on progress towards the protection and recovery of 18 species at risk, including Mottled Duskywing (2021).
What you can do
Report a sighting
- Report a sighting of an endangered animal or plant to the Natural Heritage Information Centre. Photographs with specific locations or mapping coordinates are always helpful.
- Volunteer with your local nature club or provincial park to participate in surveys or stewardship work focused on species at risk.
Be a good steward
- Private land owners have a very important role to play in species recovery. You may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats.
- Help preserve alvars and spread the word about these precious habitats. The Great Lakes region and northern Europe are two of the only places on earth with these habitats. Their limestone and lack of soil means few plants can grow, but those few plants are often rare species that require alvar habitat, and are host to rare insects such as the mottled duskywing.
- The Canada-Ontario Farm Stewardship Program is available to farmers registered under the Canada-Ontario Environmental Farm Plan to encourage greater protection and conservation of habitat for species at risk. Find more information.
- Populations of many insects that pollinate plants are declining around the world. For information on how you can easily give insect pollinators a helping hand.
Report illegal activity
- Report any illegal activity related to plants and wildlife to
1-866-MOETIPS (6638477)( 1-866-663-8477).
- The mottled duskywing lives in some of the rarest ecosystems in Ontario, such as oak woodlands, pine woodlands and tallgrass prairies. Other butterfly species with similar habitats, such as the Karner blue, frosted elfin and eastern Persius duskywing, have mostly disappeared from Ontario and Canada.
- This species of butterfly flies low to the ground in a fast, erratic pattern, making them difficult to identify while in flight.
- In mating season, male mottled duskywings often congregate on local hilltops to compete for females.