Why Millions of Monarchs Are Being Killed in Mexico

While international efforts are under way to help keep dwindling populations of monarch butterflies from disappearing, scientists are raising concerns about how severe weather and a loss of forest habitat at their wintering grounds in Mexico are affecting them.

Every year, monarchs embark on an epic multigenerational migration that takes them thousands of miles from Canada and the U.S. in search of sites in California and in Mexico. The fir trees in the southern regions offer the shelter and warmth they need to survive the winter.

Monarch Butterflies on tree branch in Michoacan, MexicoCredit: Thinkstock

Unfortunately, these vital forests in Mexico have been threatened by illegal logging, and now storms have destroyed hundreds of acres of habitat, while severe weather is believed to have killed an estimated 6.2 million of these iconic butterflies.

“Since the forests provide the microclimate needed for butterflies to survive the winter, illegal logging must be eradicated and degraded areas need to be restored,” said Omar Vidal, CEO of World Wildlife Fund (WWF) Mexico. “This would help the monarch butterfly to better adapt to extreme climate events, and also provide local communities with sustainable economic alternatives.”

According to WWF, while illegal logging is believed to have declined significantly over the past year, habitat degradation is still a problem and now climate change is posing another problem.

These fragile butterflies already face high mortality rates along their route from other threats that range from predators and parasites to a loss of habitat along their migration path. They travel north in the spring in search of milkweed plants — the only plant that monarchs lay eggs on and caterpillars eat. But these plants are being destroyed by the herbicide glyphosate, which is sprayed on fields where genetically modified Roundup-ready corn and soy crops are grown.

Monarch Caterpillar crawling up milkweedCredit: Thinkstock

According to the Xerces Society, in the 1990s, an estimated one billion  monarchs made this migration, but over the past 15 years, they’ve lost millions of acres of habitat and the number of monarchs has steadily dropped by 80 percent, or more by some estimates.

The good news is that these butterflies are not without advocates working to help them recover. Individuals are working in their gardens and communities to improve butterfly habitat. Conservation organizations are working on other measures, including seeking endangered species status for monarchs and working on habitat restoration.

This week, the National Fish and Wildlife Foundation announced more than $3 million in grants from its Monarch Butterfly Conservation Fund, which have been matched for a total of $9 million. The funds will be used to restore approximately 16,000 acres of key habitat to support monarchs’ survival.

For more info about ways to get involved in efforts to save monarchs that include creating habitat or participating in citizen science projects, visit the Fish and Wildlife Service’s Save the Monarch and the Monarch Joint Venture.

If you’re looking for milkweed plants, check out the Xerces Society’s Milkweed Seed Finder and Monarch Watch’s Milkweed Market, which both offer native seeds and seed guides by region for planting.

And sign the Care2 petition asking the EPA to protect monarchs from Monsanto.

Photo credit: Thinkstock


Sarah Hill
Sarah Hill1 years ago

This is heartbreaking. And look at what they did in Florida to fight the Zika virus! They just sprayed indiscriminately! Which killed anything and everything in their path.

joan silaco
joan s1 years ago


Melania Padilla
Melania Padilla2 years ago

Petition signed

Edith B.
Edith B2 years ago

Petition signed. I grew milkweed this summer and still only saw one Monarch and that was today. Round Up needs to be banned.

federico bortoletto

Petizione firmata

Marie W.
Marie W2 years ago

Ban pesticides and get rid of MonSatan.

Jennifer H.
Jennifer H2 years ago

I second Tammy Andrews!

Jane R.
Jane R2 years ago

Let us hope that these efforts will make a difference.

Jen S.
Jen S2 years ago

I put in a milkweed patch three years ago; the plants, grown from seeds collect from pods, are doing well and I do have Monarchs, but not in the quantities from previous years, when they would come to my cutting garden in large groups. So many issues might be addresses by the dedicated prevention of deforestation. Monsanto, Dow are the corporate equivalent of gangsters.

Robin Pasholk
Robin Pasholk2 years ago

We've got a natural prairieland preserve next to the place where I volunteer. I do an unofficial monarch count as I walk past the patches of milkweed there. So far this summer? 2 monarchs, no caterpillars, no cocoons. As Scooby Doo would say, "Rut-roh!"...