Worries grow following 'dramatic' drop in monarch butterfly population

Flight of the Monarch Day was held in Toronto Saturday, as well as various other locations across Canada, in an effort to raise awareness around declining monarch butterfly populations and ways to help the fluttering insects.

Saturday declared 'Flight of the Monarch Day' in Toronto as awareness spreads

The epic 5,000‐kilometre migration of monarch butterflies from eastern Canada to the forests of central Mexico begins in late August each year. Events took place across Canada on Saturday to raise awareness on how to curb the declining monarch population.     (Monarch Watch)

It's a trend conservationists are all too familiar with: monarch butterfly numbers across North America have been slowly declining for 15 years.  

But this year's decrease is an even greater cause for concern, with the population of the orange and black butterflies down by more than 50 per cent between the winters of 2019 and 2020. 

"[It's] a dramatic drop," said Rachel Stewart, program manager for Monarch Nation, a program run by the Toronto and Region Conservation Authority (TRCA). 

"Much as efforts to preserve and conserve monarch butterflies are increasing and to provide habitat … it's clear that there's still a long way to go." 

In 2013, the eastern population of monarch butterflies dropped by 95 per cent, resulting in the smallest recorded population of the species since the mid‐1990s. Pictured here is a viceroy, which look similar to a monarch but is slightly smaller.   (Michael Charles Cole/CBC)

It wasn't always this bleak; between 2018 and 2019 there was an unusual spike, which turned out to be a one-year blip. 

That's why Monarch Nation organized Flight of the Monarch Day Saturday in communities across Canada — events that raise awareness and support the continent-wide effort to stabilize the species' uncertain future. 

Gardeners are encouraged to plant the non-invasive butterfly weed in their gardens to help monarch populations flourish. Pictured here is a viceroy butterfly.  (Michael Charles Cole/CBC)

Toronto's flagship event took place in Tommy Thompson Park, a narrow peninsula that sits on the waterfront, tucked between Cherry and Woodbine beaches. 

The event marked one of the last opportunities this season to catch a glimpse of a monarch in the city. Viceroy butterflies, which are similar to monarchs but slightly smaller, could also be seen at the park. 

In the coming weeks monarchs across eastern Canada will begin their 5,000-kilometre trek south to Mexico for the winter. 

Monarch Nation program manager Rachel Stewart helped organize Saturday's event in Toronto, which took place at Tommy Thompson Park. People were encouraged to participate in various activies and catch a glimpse of the monarchs before they head south in the coming weeks. (Michael Charles Cole/CBC)

A new generation of monarchs will then make their way back north next spring.

"They've never been to Canada before so it's kind of neat to know they just instinctively know how to get here," said Stewart.

'We're losing ground every year' 

What's behind the butterflies' declining numbers, Stewart said, is a general loss of habitat mainly caused by farming and urban development. Climate change is also responsible for the dwindling population.

The lack of habitat also means less milkweed, which is the only plant a monarch will lay its eggs on and that caterpillars will eat, she said.

The monarchs that travel to Canada from Mexico after the winter have never been north before — they are the offspring of butterflies that travelled south and died after their migration.  (Angelina King/CBC)

While there are efforts in Canada to help with the planting and preserving of habitats, some of the major habitat loss is happening in the upper Midwest U.S., said Chip Taylor, the director of Monarch Watch, an organization that tracks the migration of monarchs. 

"Unless we're replacing at least [809,000 hectares] of habitat a year, we're losing ground every year," he said. 

Chip Taylor is pictured here showing students how to hold a butterfly. Taylor is the director of Monarch Watch and professor emeritus of ecology and evolutionary biology at the University of Kansas. (Monarch Watch)

That trend is something Toronto Mayor John Tory supports trying to curb. 

In a proclamation signed by Tory Saturday, the city deemed August 22 as "Flight of the Monarchs Day." 


"Pollinators in Toronto and around the globe are under increasing pressure due to habitat loss, climate change, invasive species and pesticides," the proclamation reads. 

"We can all play a role in protecting them."

Monarchs which migrate south gather in huge colonies to wait out the winter. Pictured hereis a viceroy. (Michael Charles Cole/CBC)

How can you help? 

If you're interested in helping, there's a couple of different ways to go about it. 

Stewart said planting milkweed is extremely effective — something that wasn't allowed in Ontario until 2014, when the plant was taken off the province's list of noxious weeds.

"There has been an awareness relatively recently that milkweed is the only plant that monarch butterflies will lay their eggs on," she said.

"If you don't have milkweed, you don't have monarchs." 

Monarch butterflies born in the summer (before mid-August) are likely to live between three and five weeks. Monarchs born later generally live for several months during the overwintering months in Mexico. (Monarch Watch)

Otherwise, if you see a monarch butterfly or milkweed you can submit photos online, which helps scientists track them.

Check out more images of monarchs in Mexico. 

Monarchs collecting water, which is used to break down fats into sugars for energy. (Monarch Watch )
Monarchs seen on the ground collecting water from dew-covered grass. (Monarch Watch)
A tree in Mexico covered with monarchs. (Monarch Watch)

With files from Angelina King


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?