I’ve been fascinated with monarch butterflies’ migration ever since reading Flight Behavior by Barbara Kingsolver. Monarch butterflies are the only butterflies that have a two-way migration (think: birds).
Using nothing but environmental cues to guide them, they fly down to Michoacan, Mexico every winter. Every single year, they do this. Every single year, the butterflies die and new ones take their places, which means there are no older butterflies to lead the way. Somehow, they just know where to go.
Butterflies usually cluster together in large groups to stay warm in the oyamel trees in Mexico. This helps them stay hidden from predators while conserving their strength for winter. They’re split into two different kinds based on their migration patterns: the Eastern Monarchs and the Western Monarchs. The Eastern Monarchs are the ones that fly down to Mexico every winter, while the Western Monarchs fly to California. Less is known about Western Monarchs, but the California climate is similar to that of the climate Eastern Monarchs experience in Mexico.
The Monarch Butterfly Biosphere Reserve in Mexico (which I’m really trying to visit one day) has been considered a World Heritage Site since 2008 (by UNESCO). The protected area is 200 square miles, creating a somewhat safe place for the Monarchs to be every winter. There are several other butterfly reserves in Mexico as well.
Monarchs are stronger than you think, but they’re still fairly delicate and thrive in a limited range of temperatures. They cannot fly when the temperature dips under 55 degrees Fahrenheit. For them to not be able to fly is deadly for the butterflies. Which is frightening, because this means climate change can have a big influence on their migration patterns, with changing temperatures causing habitats to shift. And if the butterflies’ migration is off, that means something is wildly wrong.
Other fun facts about Monarchs:
- During migration, butterflies can cover up to 80 miles in a day.
- They travel an average of 1,800 miles from Canada and the U.S. to Mexico.
- They travel at an average speed of 12 mph (but can get up to 30 mph!).
Anyway, butterflies are pretty cool and there are a few things we can do to help them along their journey down south, such as planting milkweed (butterflies can’t survive without it) and flowers that attract butterflies (because of the nectar). Stay away from using insecticides on plants, and limit use of herbicides to keep from poisoning any butterflies.