Monarch butterflies lead a mysterious life. Generations pass in a summer season like other lepidoptera. Then as autumn approaches, one brood takes to the sky and heads to Mexico. In January I went to see the winter roosts of the millions of monarchs and the experience was inspiring.

As I planned the trip with my husband Jim, we thought we knew a little something about Monarchs. We had raised Monarchs from eggs we collected last summer, feeding milkweed to the caterpillars. The pupae have a jewel-like appearance with gold flecks in jade green. Adult butterflies emerge with wet wings and take their time getting accustomed to their new ability to fly.

From articles in magazines and internet sites such as Monarch Watch and Journey North we had learned about Fred Urquhart, Kenneth Brugger and Lincoln Brower who dedicated years to studying the butterflies finally locating the over-wintering sites in the Neovolcanic Mountains of Mexico in the 1970's. We read about tagging programs to track the migration routes as long as 2500 miles. We knew we'd be visiting sanctuaries, which protect the monarchs and the oyamel trees they roost in. Oyamel trees grow at an altitude of about 10,000 feet where the cool temperatures keep the immature monarchs from rushing through life. Tourists must be prepared for the hike at that height - we would carry lots of water along with our cameras. The people who live in these mountains and own the land are coming to accept ecotourism as a supplement to their income.

Many visitors come to the town of Angangueo as the jumping off point to El Rosario and Chincua sanctuaries to view the butterfly-covered trees. Monarch Watch had asked us to purchase tags that might be available and return the migration data to the University of Kansas. Local schools don't have much, so we took some school supplies with us (you can adopt a classroom through Monarch Watch). So, Jim and I packed our expectations and headed south.

What we weren't prepared for was the wonder and awe that the hikers are stunned by when butterflies fly down the mountain in what looks like a river of orange in the forest sky. The experience of standing in a group of adults all stricken with child-like joy at the sight of "fairies" as the monarchs flit in a sunny spot in the woods isn't in a book. We all waited silently just listening to wings beating and looking at how many more butterflies were still clinging in uncountable numbers in the Oyamel trees.

I can't wait to find those eggs on the milkweed this summer and help raise the next generation of migrators. We'll send them on their way to Mexico to continue the mystery.

Read other articles on birds, wildlife & beneficial insects