Why Do the Butterflies Migrate?

Inarguably the most important driver for them is food, and pecial milk wheat plants. Another reason why they migrate is to ride out the winter in the sierra madre mountains near mexico cityl so there might be ten million butterflies or more in a single colony. By early march, it's time to procreate. So the butterflies leave the mountains for northern mexico and texas to lay their eggs on milkweed,. The only plant that their caterpillars will eat.