Monarch Butterfly Field Notes from Mexico by Dr. Bill Calvert

Field Notes from Mexico by Dr. Bill Calvert

February 18, 2004

Dr. Calvert Calling Journey North from Mexico

(Audio File mp3)

We, meaning the Ordean Middle School from Duluth and St. Hubert’s School of Minneapolis, Minnesota left Mexico City on Sunday morning, arriving in vicinity of Cerro Piedro Herrada around noon.

We saw a few butterflies as we approached that portended the spectacle ahead. Butterflies were streaming off the mountain, especially in the Arroyo Dos Palomas. They crossed the road whose traffic had slowed to a crawl, and proceeded to the watering spots along the irrigation channel. We were delighted.

It is likely that this was the first really warm spell since storm that occurred at the end of January. Thirsty butterflies were taking this opportunity to descend to water as the high areas near their colony dried up.

We were also delighted with the birds. We saw all the endemics--Red Warbler, Tufted Flycatcher, Golden-browed Warbler, Gray Barred Wren and the White-Striped Wood Creeper--all except the mountain trogon.

Maps and images of monarchs at their winter refuge in Mexico.

NASA Visible Earth

The following day we trekked up to El Rosario to a mild disappointment. The colony is very dispersed. There are 3 loci on the mountain north of the Llano de los Conejos. The one that we were led to had very small, scattered clusters.

The ground was covered with dead butterflies and there was a faint stench of decaying stench of decaying butterflies in the air. We were informed that the storm brought 8 inches of snow but, worse for the butterflies, extremely high winds and cold temperatures. The high winds, they said, had blown all the butterflies down from their clusters. What we were seeing represents those that had warmed after the snow melted and had flown up to reform clusters.

At Chincua the scene was very much more happy. Butterflies filled the park-like forest on the north slope of the Sierra Chincua. The colony consisted of many healthy clusters, some of which were bright orange in full sunlight. [*The butterflies are in a new canyon in Chincua, one that I’ve never seen them in before. But this doesn’t mean they haven’t been there. No one hardly checks that canyon. They say there’s only one group at Chincua and it’s not very large. It’s probably a half a hectare.]

Both of the colonies, Chincua and Rosario, were small however. Both required a long, hard walk to reach. The storm had taken a large number of them this year. More at Rosario than at Chincua, which was lower down, in a more protective forest.

We only hope that breeding conditions in the north will favor a full recovery. That butterflies will find full fields of milkweeds as they return to the southern United States.

*This section of audio was removed due to poor quality.