Map from U.S. Forrest Service
Monarch butterflies are some inspiring creatures. They migrate every winter to escape the cold winters in North America. Monarch butterflies typically live where there is a high population of milkweed, which is the only thing a monarch larvae will eat. Monarchs are seen throughout North America, and in some regions like California, they won't have to migrate because it's warm enough year round. In most cases, the butterflies will have to take the journey south to Mexico. In the map to the right, we will follow some locations in North America where there are a high number of Monarchs, see where their multiple flyways meet, and see where they end up spending the winter in Mexico. These observational creatures know exactly when and where to go, and are prepared to leave at the drop of a hat.
Some Monarchs will travel up to 3,000 miles just to reach the warmer climate in Mexico. The butterflies rely on environmental cues to indicate when it's time to travel south. The first sign is when the days grow shorter in the fall, they notice that each day gets shorter and that's usually their first indicator that it's time to migrate. The emergence of fall brings fluctuating temperatures as well, this will cause the butterflies to cluster to keep warm, which is a sign for them to leave. The final sign is when milkweed plants begin to turn yellow. This means that the plant isn't getting enough water, so butterflies will keep from laying their eggs and migrate instead of reproduce. They listen and observe their surroundings which allow them to know when to get the heck out of Dodge.
Once they reach Mexico, they will typically stay from November to March. Once they reach Mexico, they will rely on the food they ate before they got there. You can look at their abdomen and see if it's thick or thin, the thicker it is means that they have more fat stored. They also like Mexico because it's warm enough for them to stay alive, but cool enough to slow their metabolism. They tend to cluster where there are a lot of pollinators and water nearby.
Monarch butterflies only live up to about 7 week at most once they've transformed into a butterfly. Most of the time, they won't have to worry about migration because of that short life span. But by relying on environmental cues, they're able to determine when and where to go. They're extraordinary creatures that are very kind and smart.
View details »