Endangered Mottled Duskywing butterfly making comeback thanks to dedicated scientist team

An endangered species of butterfly is making a comeback in Ontario thanks to the work of a group of researchers. The Ontario Butterfly Species at Risk Recovery Team was formed in 2017 and has dedicated the last four years to the recovery of the Mottled Duskywing butterfly.

Thanks to recovery efforts, more than 700 butterflies were released this year at Pinery Provincial Park

A black and brown butterfly with a blue tag on its wing seen on leaves of a plant.
The Mottled Duskywing butterfly was almost extirpated from the province and now a dedicated team of researchers from southern Ontario is trying to restore its population. (Supplied by Jessica Linton)

A recovery team made up of researchers and organizations from across southern Ontario are working to save a type of  butterfly they say was "dangerously close" to being extirpated from the province.

And for the first time in decades, over 700 of the endangered Mottled Duskywing butterflies were released at Pinery Provincial Park this summer.

"Both personally and professionally, it's really rewarding since I've been interested in working with the Mottled Duskywing since 2007," said Jessica Linton, senior biologist with Natural Resource Solutions Inc. in Waterloo.

Linton is chair of the Ontario Butterfly Species at Risk Recovery Team (OBSRRT), which was formed in 2017 and has dedicated the last four years to the recovery of the Duskywing butterfly.

Linton is also the author of a recovery strategy on the Mottled Duskywing butterfly for the province.

She said the team's focus to recover the Duskywing butterfly centres on it being one of the last species of butterfly that lives and thrives on what is a now rare habitat in North America called Oak Savanna. 

"There use to be several rare butterflies associated with this Oak Savanna habitat ... there was four of them, the Duskywing being one of them, and the other three no longer occur here in Ontario," she said.

"We don't want to lose that last species."

Saving the Duskywing butterfly population, said Linton, also goes hand-in-hand with the recovery and preservation of the Oak Savanna habitat.

More than 700 of the endangered Mottled Dukywing butterfly were released at Pinery Provincial Park this summer. Jessica Linton (first from the left) and Adrienne Brewster from the Cambridge Butterfly Conservatory (third from left) are part of a recovery team that help with the preservation of the species. (Submitted by: Jessica Linton)

Why is the Duskywing endangered?

There are a few reasons behind the endangerment of the Duskywing butterfly, according to Linton, but it largely has to do with the loss of habitat.

The species has been extirpated, meaning it no longer exists, in Quebec, but few existing populations can be found in southern Ontario in areas like the Rice Lake Plains, Halton region and around Lake Simcoe, she said. The species can also be found in southern Manitoba. 

"The initial loss of this species and fragmentation of its habitat would have possibly been due to larger scale habitat loss that occurred after European settlement and land was cleared for agriculture," Linton said.

That left pockets of habitat in southern Ontario that faced pressures through urban expansion, industrialized development, intensified agriculture and invasive species.

The Oak Savanna also relies on natural burning to maintain an open canopy, Linton added, which would have traditionally been done by Indigenous communities on the land. 

"That doesn't really happen anymore," she said.

That's why the team landed on Pinery Provincial Park as the new home for the Duskywing butterfly. Linton said the park has gone to great lengths to recover and preserve the Oak Savanna.

Adrienne Brewster from the Cambridge Butterfly Conservatory and Ryan Norris from the University of Guelph are seen working in the field. (Submitted by: Jessica Linton)

Optimism on species' reintroduction

Members of the recovery team are monitoring the butterflies everyday. The butterflies were released in three different life stages, which will give researchers a better idea of when they should be released going forward, said Ryan Norris professor of integrated biology at the University of Guelph. 

It's rigorous work, but Norris said based on what they've seen so far, he's hopeful that they will see the Duskywing butterfly next year.

"We've hit a couple of major milestones already with the release," he said. 

He said the released adult butterflies have remained in their new habitat and saw the females of those released butterflies lay eggs in the area. Norris said they also noticed the butterflies that were released in their crystal form emerge from their pupa.

"All of these are really great signs," he said.

"You never know what's going to happen with these things. We're introducing a species to an area that they haven't been in 30 years, so anything could happen."

The Cambridge Butterfly Conservatory was responsible for the captive growth of the Mottled Duskywing butterfly before they were released. It's a process also known as captive rearing. (Cambridge Butterfly Conservatory)

Adrienne Brewster, executive director and curator at the Cambridge Butterfly Conservatory, also shares that optimism.

The conservatory has been part of the recovery effort of the Duskywing butterfly for several years and were responsible for raising the butterflies in captivity, a process called captive rearing.

"Next year's monitoring, and monitoring in subsequent years, will really help us understand if this reintroduction took hold and I'm pretty optimistic about it because we had such great numbers for reintroduction," Brewster said.

The release at Pinery Provincial Park is the first of several releases the team will be conducting over the years.

Linton said the recovery team is now looking at other sites in southern Ontario that could be new homes for the Duskywing butterfly. They are looking at Norfolk County next.

"There are several properties that the Nature Conservancy of Canada has been doing an excellent job of restoring and they are in close proximity to locations where the butterfly use to occur as well," she said.

Listen to the full interview below with guest host Jackie Sharkey:


To encourage thoughtful and respectful conversations, first and last names will appear with each submission to CBC/Radio-Canada's online communities (except in children and youth-oriented communities). Pseudonyms will no longer be permitted.

By submitting a comment, you accept that CBC has the right to reproduce and publish that comment in whole or in part, in any manner CBC chooses. Please note that CBC does not endorse the opinions expressed in comments. Comments on this story are moderated according to our Submission Guidelines. Comments are welcome while open. We reserve the right to close comments at any time.

Become a CBC Member

Join the conversation  Create account

Already have an account?