As the day heats up at Mexico's 217-square-mile Monarch Butterfly Biosphere Reserve, the insects fly to cool off. Scales fall from their wings, and black and orange glitter fills the air.
Within the reserve, four butterfly sanctuaries are open to the public: El Rosario and Sierra Chincua, in the state of Michoacan, and La Mesa and Cerro Pelon's El Capulin, in the neighboring state of Mexico. The monarchs start arriving in mid-November and stay through mid-March, before returning to their summertime homes, as far as 3,000 miles away, in the eastern U.S. and Canada. The butterflies nest above 10,000 feet, and visitors usually must walk a mile or two to reach them, so it's best to hike slowly, drink plenty of water, and bring warm clothing in case of bad weather.
The city of Morelia, served by nonstop flights from Mexico City, Houston, and Los Angeles, is the best launching point for visitors. Ten-hour guided trips from MMG Tours leave Morelia on most mornings and head to El Rosario or Sierra Chincua (011-52/443-340-4632, mmg.com.mx, $50). Rocamar Tours' two-night package includes guides, transportation, lodging in Morelia and at the foot of the mountains in Zitacuaro, and a visit to El Capulin and either El Rosario or Sierra Chincua (866/762-2627, rocamar.com.mx, $370 per person double).
A more in-depth tour, G.A.P Adventures' nine-night Mexico Monarch Butterfly Trail package--with transportation from Mexico City, visits to sanctuaries, horseback riding, and other adventures--will be offered in early 2008 (800/708-7761, gapadventures.com, from $795).
Going It Alone
There are no sanctuary websites or reliable phone numbers, but the World Wildlife Fund posts information about services--horseback riding, cabin rentals--at the sanctuaries, as well as detailed driving directions, at wwf.org.mx. Park admission ($2-$5) includes a tour guide who probably won't be fluent in English.
Researchers attach plastic ID tags to some butterflies' wings. If you see one, report the tag number and location to monarchwatch.org.
For Social Butterflies
Angangueo, a colonial town 45 minutes by car from El Rosario, makes an ideal base for independent sightseers (Hotel Don Bruno, 011-52/715-156-0026, from $70). The town hosts dance and craft shows during the month-long Monarch Festival every February.