In late February Sandy and I had the immense pleasure of visiting two of the Monarch overwintering sites in Mexico. Although we had visited a few of the overwintering sites of the western Monarch population in California in the late 1990s, this was our first visit to any of the sites in Mexico.
Monarchs typically gather in overwintering colonies at several sites in the Transvolcanic Mountains of Mexico in the Mexican states of Michoacan and Mexico. Most are closed to the public but there are at least three that are open. El Rosario, in the state of Michoacan, has the most developed trail system, the most number of visitors, and usually the highest number of Monarchs. Sierra Chincua, also in the state of Michoacan, is perhaps the second-most heavily visited by tourists, and usually has good numbers of Monarchs, and Cerra Pelon, in the state of Mexico, is probably the third-most visited by tourists, and usually has good numbers of Monarchs. During our trip, we visited the first two.
After a few days in Mexico City to get acclimated to the culture, food, and altitude, and to allow a visit to the city’s incomparable National Museum of Anthropology, we ventured about three hours northwest of Mexico City to the old mining town of Angangueo, the town closest to the Monarch colonies. From Angangueo, it is about a 30-45 minute drive to El Rosario. From the parking lot there is a trail up to the Monarch colonies. You can either walk up the foot trail, which takes about an hour or an hour and half depending on your condition and how much you “feel” the altitude (the colony is somewhere around 10,000 feet), or you can ride a horse up via the horse trail—which we did on the second day of our visit. The cost is about 70 pesos (less than $7 US). It is a very relaxing way to get up to the colonies and is considerably quicker. You can also take a horse to go down if you prefer, for another 70 pesos.
The foot trail is fairly steep so you will want to take it slow. The walk up is through a delightful forest, littered with flowers, some of which attract hummingbirds, others are important nectar sources for the Monarchs. As we gained altitude the pines of the lower elevations gave way to the beautiful Oyamel Firs (Abies religiosa), the trees in which the Monarchs form their overwintering clusters. Soon we began to see small groups of Monarchs hanging from the branches. These small clusters, however, in no way prepared us for what we were about to see. We finally reached the “llanos,” an open area of short grass and shrubs, bisected by a stream, an important source of moisture for the Monarchs. Beyond the llanos we re-entered the woods, and shortly arrived at an area roped off with caution tape. This was the area where the main overwintering colony had formed. The colonies are roped off each morning by the Preserve guards (on warm days in February the butterflies go out to feed and when they return to the colonies they often settle at slightly different locations so the clusters shift a little each day). It was still early in the day and quite cool, and we peered into the dark forest. There were hundreds of Monarchs flying around through the patches of sunlight, but this too, did not prepare us for what was to come. We finally realized that the huge grayish-brown clumps, which somewhat resembled the spanish moss we had seen hanging from the trees in Florida and Georgia, were actually millions of Monarchs. As the day slowly warmed, more of the Monarchs began to move, and eventually the forest was filled with orange wings, appearing and disappearing as they flew through the beams of sunlight. We returned to the llanos and watched as thousands of Monarchs came to the creek for moisture and the flowering shrubs for nectar. In mid-afternoon, what must have been virtually the entire colony exploded from the firs and sought moisture and nectar before returning to recolonize the firs in late afternoon. The afternoon flight was one of the greatest natural history spectacles we have ever witnessed—a virtual blizzard of orange wings. In fact, there were so many wings that the wing beats were easily heard.
Sierra Chincua is about 30 minutes from Angangueo in the opposite direction. It is a bit more rustic but still has nice trails. The hike is a little longer but less steep. Horses are also available here, and we took them both ways so we have no direct experience with the foot trail. I’m not sure if it is known why, but many of the clusters at Sierra Chincua form on the trunks of the Oyamel Firs, rather than just hanging from the leaves, as they do at El Rosario. Our day at Sierra Chincua began cool and cloudy, and no Monarchs moved until early afternoon. It was so cool in fact, that the moist air that is so critical for keeping the Monarchs hydrated as they hang dormant for much of the winter could be felt on the paper of Sandy’s notebook. I was happy for the coolness, for it gave me plenty of time to try to photograph a fir trunk incrusted with Monarchs, one of my goals of the trip. Finally, at about 1 PM, the clouds thinned and parted, allowing some patches of sunshine to briefly hit the colony. A few Monarchs slowly dropped from the tree trunks and flew away, moving through the forest to seek nectar and moisture at a creek lower down the mountain. Many stayed close to the firs, circling around the grove, and when the clouds returned we saw Monarchs dropping onto the nearest branches, too cold to fly. Finally the sun burned off the clouds, and the air was once again filled with orange wings. Although not as impressive a flight as at El Rosario—this is a smaller colony—it was still an incredible sight.
In late afternoon we rode the horses back down the mountain, our minds filled with memories that will last a lifetime. If anyone would like further details about our trip, or some insight into the logistics of visiting the Monarch reserves, feel free to contact us through the contact page.