When it is ready, it breaks out and flies away. Migrating butterflies Butterflies don't look like strong fliers, but species like the painted lady migrate huge distances to escape cold winters. The monarch is the most remark-able. Every autumn, huge clouds of monarchs leave eastern North America and fly south for 3200km to winter in the Mexican mountains. What is amazing is that none of them have made the journey before, for they are barely a month old.
Monarchs live only six weeks, and it was their great grandparents that flew north in the spring.
Yet the monarchs know just where to go, to the precise tree. When monarchs reach their winter home in the Mexican mountains after their long migration, they huddle together in huge numbers on trees for warmth. There they stay until the following spring, when they all head north again to spend the summer breeding. But there are 17,700 known species of butterfly, including skippers, metalmarks and snouts, whites and sulphurs, blues, hairstreaks and coppers, swallowtails, and nymphs. The largest group is the nymphs, of which there are almost 6000 different kinds, including red admirals, viceroys and mourning cloaks.