The Great Butterfly Journey
Every fall, millions of monarch butterflies in eastern North America begin an incredible journey. From fields and gardens across the United States and Canada, they fly south — sometimes over 3,000 miles — to reach a few tiny patches of forest high in the mountains of central Mexico.
These butterflies have never been to Mexico before! The monarchs that make the fall migration are the great-great-grandchildren of the ones that left Mexico the previous spring. Yet somehow, they find the exact same trees their ancestors roosted on.
The fall migrants are a special 'super generation.' Unlike summer monarchs that live only 2-6 weeks, fall monarchs enter a state of suspended aging called diapause. They can live 8-9 months — long enough to fly to Mexico, overwinter, and start the return trip.
In Mexico, the butterflies cluster together on oyamel fir trees by the millions. The trees drip with orange wings. The mountain forests are cool enough to slow the butterflies' metabolism so they use minimal energy during winter.
**Wow Factor:** A single tree in Mexico can be covered with over 10,000 monarchs! The branches literally droop under their weight, and the whole tree appears to be made of orange wings.