Monarch Butterfly Field Notes from Mexico by Dr. Bill Calvert

Field Notes from Mexico by Dr. Bill Calvert

March 18, 2004

Photo: Jim Edson

Dr. Calvert Calling Journey North from Mexico

(Audio File mp3)

NASA Visible Earth

This week we are a very mixed group of mainly school teachers and college professors. We visited two butterfly reserves, at Cerro Pelon and Chincua.

The trek to the Pelon colony was straight up the mountain, or at least it seemed so--but probably more to the steaming, sweating horses that carried us, than to us. Butterflies were streaming down the mountain in several arroyos. The direction of these drainages was south, the wrong direction home. At one point, after spilling out of the arroyos onto the road, they seemed to reverse direction and fly northward.

The forests on the south face of Pelon were different from the others we had encountered. They were noticeably wetter. Instead of the near-monocultures of yam with occasional pine found at Chincua and Rosario, this forest consisted of many broad-leafed species, including tepusans, alders, several species of oaks, madrones and madrone relatives. Many of the tree trunks and branches were completely covered with mosses. Bromeliads were abundant. The dominant species in the forest was the cypress. Bird life was much more abundant. Elusive trogons called to us on our way by.

The Pelon colony was in the process of breakup. This was evidenced by the presence of monarchs pouring out of the arroyos at the base of the mountains, and by the scarcity of dense clusters in the main site populated by tens of millions only last week. Only Chincua maintains some integrity, still occupying at least two hectares of area. In spite of low numbers at Pelon, the presence of flying butterflies in all parts of the forest delighted everyone. Also of delight was the seemingly content people of Macheros, who live in the beautiful valley of woods and cornfields.

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

NASA Visible Earth