Monarch Butterflies Hit Hard This Winter

The latest news on the Monarch Butterfly is cause for deep concern.

Surveys conducted this winter in the Mexican Highlands, where the bulk of the Monarch population overwinters, has revealed that the Monarch population dropped 15% from December 2016 to December 2017.

The population now occupies only 2.48 hectares (ha) of land. Since the counts were initiated, the greatest amount of land occupied was 18.19 ha. The current area of occupation represents a decline of almost 90% since the highest count in 1996. The figure below provides details of the overwintering counts.

monarch overwintering population in mexico
The graph depicts ups and downs in the population over the years, which likely was normal for this species. However, the downward trend without recovery years is very concerning. Over the past six years, the three lowest populations ever were recorded!

Why are Monarchs Declining?

monarch on orange flower

Scientists have listed the main cause of the decline to include habitat destruction on both breeding and wintering habitat. Also, use of pesticides and herbicides on agricultural lands, and climate change impacts have hurt this species. More recent research in the U.S. points the finger at yet another issue: diminished sources of nectar-rich plants along the migratory pathway. Nectar is the fuel that Monarchs need on their incredible journey from Canada to their overwintering grounds. Monarchs need to refuel regularly. The loss of nectaring wildflowers along their migratory path makes it hard for Monarchs to restore their depleted energy reserves. It would be similar to the removal of about one half of all gas stations along our vacation route. We would have difficulty refueling and might run out of gas.

Why did the Monarch Population Decline this Year?

Many of you rejoiced last summer when you saw many adult Monarchs flying in southern Canada. It seemed to be a banner year, especially in Ontario and Quebec. Here at the Canadian Wildlife Federation, we held hope that this would be a recovery year. So what happened to the population? One of the main culprits was the fall hurricanes that struck the southern U.S. this fall. Another culprit was the warmer than usual weather, which delayed migration in some parts of Canada and the United States. Both may have also contributed to reduced numbers in 2017.

Climate change brings extreme weather and increasing variability in weather. Climate change scientists predict increasing extreme weather events and more variability of weather. This will not likely be an advantage for the struggling Monarch population.

What is Being Done About the Decline?

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC), which is tasked with assessing species and recommending listing to the federal government, has recommended that the Monarch be listed as Endangered under the federal Species at Risk Act. In Ontario, the Committee on the Status of Species at Risk in Ontario (COSSARO), the group of experts tasked with listing species under the province’s Endangered Species Act, will likely decide this year whether to list the Monarch as Endangered. An endangered listing will spark the creation of a Recovery Strategy with specific conservation action plans.

In addition to government action, there is plenty of good science happening for Monarchs. Maxim Larrivée’s team at the Montreal Insectarium and colleagues are researching whether milkweed is limited in Canada. Milkweed is the host plant that Monarch larvae depend on for survival, and there are several species of Milkweed in Canada. The results of this research will help us to understand the impact of changing land use on Monarch as well as whether we should target restoration of milkweed host plants to aid the recovery of Monarch.

Monarchs grouped

On other science news, a Canadian study led by Tyler Flockhart determined that habitat in Canada contributed a relatively high proportion of the overwintering Monarchs in Mexico, considering Canada comprises a small portion of the total range of Monarch. The research team looked at chemical isotope signatures from Monarchs on the overwintering habitat to determine where the butterflies were born in the previous summer and fall. They found that 12 per cent of the insects were born in the northwestern U.S. and Canadian Prairies, 17 per cent in the north-central States and Ontario, 15 per cent in the northeastern U.S. and the Canadian Maritimes.

What is CWF Doing for the Monarch?

It will take large scale restoration efforts to increase breeding and nectaring habitat. The Canadian Wildlife Federation is forming partnerships with right-of-way corridor (e.g. roadways and hydro-electric) managers to conduct habitat restoration trials, including:

We aim to document the cost and conservation benefits of restoring Monarch habitat, which will inform restoration practices at a large landscape scale.

CWF also continues to engage school groups and citizens like you to plant milkweed and native wildflowers to provide for Monarch during breeding and migration. Everyone can help to restore Monarch habitat!

Let’s Do More for the Monarch!

To compensate for ever increasing impacts of climate change and agricultural intensification, habitat restoration throughout breeding and overwintering habitat will need to overachieve conservation outcomes. In other words, restoration efforts will have to be bigger and better than ever before. It will take a concerted effort of federal, provincial, federal governments as well as private landowners to make this happen. Together, we have to knock it out of the park for the Monarch!

Learn how you can Help the Monarch!

Momma’s Monarch Watch

Like so many good things, it all started on a languid summer day at the cottage. The kids had fished and caught frogs, and it was still too cool for a swim. It was time to check the milkweed!

Ever since my Grade 3 teacher brought in Monarch caterpillars to the classroom, I’ve casually checked the undersides of milkweed leaves for the familiar stripy larvae. I never found much. But then last summer my neighbour, who has reared generations of Monarchs and Swallowtails, suggested we search for the eggs because they can be quickly predated. In his experience, caterpillars are much harder to find. And so this summer, voila, success. The first was named Savanna, quite aptly I thought, who was quickly followed by Sunny, Summer, Tiny and Sunset. It turns out that once you start on this road, it’s hard to stop. We watched our eggs hatch, caterpillars grow by orders of magnitude and fledgling butterflies emerge. It was all incredulous and addictive.

But with summer camps and busy work schedules, the one stage we had not yet had the luck to observe was the appearance of the chrysalis. Only once in my life had I witnessed a Monarch pupating. I knew that this was a natural phenomenon so incredible, so miraculous, that everyone should see it at least once. Unfortunately that can be difficult because the entire process can happen at any time, and it’s so fast that you can almost blink and miss it.

Pupation in Monarchs is not the lengthy cocoon-building process that you might imagine. The entire chrysalis is fully formed under the hanging caterpillar’s skin. The visible stage of pupation, most amazingly, is really a shedding of the stripy outer skin, which is shrugged off, antennae and all, by the lumpy lime green pupa underneath. Once it has wiggled into its final shape, the chrysalis becomes still for a week-long, silent internal transformation. The whole thing takes perhaps two minutes, and cannot fail to leave you in a state of complete and utter amazement.

So when our very last caterpillar was hanging in its familiar J-shape ready to go late one evening as we packed for our summer canoe trip, my husband and I had eagle eyes on the jar.  Of course, at ten minutes to midnight, my husband called: “I think the antennae are looking straggly.” According to our recently acquired web-expertise, this indicated that the skin had loosened for the final shed of pupation, which was imminent.

And so the watch began. There was no way I was missing this one. I made a cup of tea and sat down next to the jar like an anxious parent in a waiting room.  With an early morning drive and a long day to come, by 12:30 a.m., I was pretty sure I was nuts. 12:45….1:10… Hmm, perhaps certifiably insane. Was I prepared to wait all night?

By 1:15, some squeezing movements began, and my long-suffering husband was summoned from slumber. At first, there was the tiniest split in the outer skin. Should we wake the kids? They had tended to these fragile creatures for weeks, and the answer was clear to both of us – of course we should! So there we all were, at 1:20 a.m. on a dark summer’s morning, huddled around a Mason jar, watching a miracle.

Within just a few minutes, the skin lay cast off and the pupa was still. “That was so cool,” enthused our 11 year old. Her younger brother, who was not so wide-eyed, murmured a yawning “Yah,” followed by “Sleep is cool, too,” and then shuffled off wordlessly in the direction of his bed.

At least as cool is the final emergence of a perfect adult butterfly from its transparent chrysalis. Each emergence was a bittersweet celebration as we released our delicate, unblemished charge for what we knew to be a long and arduous journey to the Mexican highlands.

With our newfound skill at egg-finding, we’ve now spread the Monarch love to several neighbourhood families. As a Monarch Momma friend says, it never gets old. Like a solar eclipse or the coral spawn, watching this metamorphosis first-hand should be on everyone’s life list of natural phenomena. It’s well worth the wait!

Learn more about Monarch Butterfly and what you can do to help these at-risk migrators.