Cherished Eastern Monarch Butterflies Are Flourishing

There’s some encouraging news about monarch butterflies, reports the World Wildlife Fund (WWF). According to a new report released in Mexico, the eastern monarch butterfly population, which breeds east of the Rocky Mountains, according to The Gazette, nearly doubled between 2024-2025. 

While populations remain below the long-term average, the population wintering in the high-elevation fir forests of central Mexico occupied 4.2 acres, a jump from 2.22 acres over the previous winter. Scientists credit this growth to better weather conditions, with a less severe drought along the monarch’s migration route, as well as a decrease in forest degradation. The Guardian also attributes what it calls a “modest growth in numbers” of these orange and black butterflies to years of conservation efforts.

According to the Guardian, Jorge Rickards, the director general of Mexico’s WWF branch, has acknowledged the need to convert the short term gains into long term ones for monarchs to stop being considered as endangered: “It’s now time to turn this year’s increase into a lasting trend with an all-hands approach where governments, landowners, conservationists, and citizens continue to safeguard critical habitats along the monarch’s North American migratory route.”

Counting the Vibrant Monarchs and Identifying Conservation Threats

This WWF report is based on the most recent edition of an annual survey, “Forest Area Occupied by Monarch Butterflies Colonies in Mexico During the 2024-2025 Hibernation Season.” It is conducted by WWF-Mexico and Mexico’s National Commission of Protected Natural Areas, with the help of local communities, and acts as a barometer of the overall health of this treasured butterfly population. 

Related reports, such as Forest Degradation at the Core Zone of the Monarch Butterfly Biosphere Reserve (2023-2024), the WWF quotes, reveal a welcome decline in forest degradation due to illegal logging, drought, and the legitimate removal of trees to prevent the spread of disease.

Interestingly, as the monarch conservation body, Monarch Joint Venture, details, instead of counting individual monarch butterflies, scientists estimate the population size by measuring the area of the trees the butterflies are occupying (in hectares). This, as the Guardian points out, is seen when trees turn a vibrant orange by the clusters of bright butterflies.  

Each hectare is approximately 2.47 acres, which equals the size of just over two American football fields. According to a 2016 study published in Nature, a threshold of at least six hectares of overwintering monarchs is recommended to support a sustainable eastern migratory population. The current population remains below this target, underscoring the need for continued conservation action.

This news is music to the ears of monarch butterfly fans, as these butterflies face several threats. These include climatic variations in the monarch’s breeding areas in Canada and the United States that can impact the quantities of milkweed, the sole plant on which monarchs lay their eggs, and the continuing forest degradation in the overwintering sites in Mexico. Extensive use of herbicides and pesticides, meanwhile, have also driven the reduction in milkweed and other nectar plants that adult monarchs feed from. In addition, according to Monarch Joint Venture, monarchs face many risks from natural enemies such as predators, parasitoids, and disease. 

Saluting and Protecting Monarch Butterflies
As the WWF emphasizes, monarch butterflies play their part in maintaining a health ecosystem across the US. With 80 percent of agricultural food production relying on pollinators like monarchs, protecting them benefits everyone.

Each year, at the end of summer, these popular insects journey from southern Canada and the northern US to mountain forests in Mexico; for some a journey of 3000 miles (4828 kilometers.) When winter ends, these same butterflies fly 600 north back to the US to lay their eggs on milkweed plants, most of which, according to the US Forest Service, are found in the Midwest. The next three to five generations live for three to five weeks, continuing the northward migration, eventually reaching the breeding sites in the northern US and Canada.

Significantly, according to the US Forest service, the lifespan of monarchs varies, with the last generation of the year, or the late summer butterflies, living for up to nine months, rather than the typical two to eight weeks. This is because they enter a non-reproductive period, giving them far more energy, while they benefit from living in cooler temperatures that slow down their metabolism.

Monarchs are still considered a species at risk by environmentalists, according to the sustainability-focused Center for Food Safety. It highlights that in Canada, Monarchs are slated for listing as endangered under the Species At Risk Act, while they are considered a species of special concern.

So how can you help boost monarch conservation? Monarch Joint Venture urges members of the public to help create monarch-friendly habitats, particularly by planting milkweed and nectar-rich flowers to support these butterflies throughout their life cycle. It also encourages them to participate in community or citizen science, helping researchers track monarch populations, their migration patterns and their health.

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