Our roommate had friends visiting and since they were going and Edson had never been, we made the last minute decision to join them for a day trip. (I went for the first time with Karen in 2011, which you can read about here).
We visited El Rosario Butterfly Sanctuary in Michoacán.
Monarchs are the only type of butterflies that have two-way migrations, like birds do. They travel some 3,000 miles between Mexico and the Northern U.S. and Southern Canada. They spend November through March "overwintering" (ie - how insects spend the winter) in oyamel fir forests in the mountains of Michoacán and the State of Mexico.
On my first visit, I learned that their lifespan isn't very long, so the migration is completed over the course of multiple generations and somehow they keep returning to the same places. Whoa!
This time we learned that most Monarch butterflies only live 3-5 weeks, but when it's time to migrate a special generation is born, which lives 7-9 months. That's a big difference!
Confused about the two explanations? I was too. Thanks to Google (and the US Forest Service and Monarch Watch), I was able to clarify that the special migrating generation makes the trip all the way from the U.S./ Canada to Mexico, spends the winter in Mexico, and then makes part of the trip back before they die. New generations of Monarchs are born along the way, so the rest of the northern migration is completed over the course of multiple generations. Then, once again, a special migratory generation is born in time to make the trip South and, even though they've never been, they somehow find their way to the mountains in Mexico.
It was a pretty cold day (by Michoacán, Mexico standards), so there wasn't too much movement going on. However, it was still INCREDIBLE to see all of the Monarch butterflies clustered on the branches and trunks of the trees. In the photos and video below, all of the orange/brown "dead leaves" are butterflies!