Field Notes from Mexico Contributed by Dr. Bill Calvert March 12, 2001 The snow is gone from nearly everywhere but the highest elevations. Still much vegetative carnage remains at elevations of the butterflies colonies and below. The areas to the west and south of Nevada de Toluca was especially hard hit by last week's storm. Many trees were uprooted and branches were down some of which were across the road and have subsequently been cleared away. Since it never became very cold following the storm, most of the butterflies were spared. (It's during the cold, clear nights after a storm that wet butterflies are particularly susceptible to freezing.) The recent clear weather has brought many cloudless skies. Today we visited the area below the Herrada colony where conditions were perfect for descent from colony to water. Since we only saw two butterflies we must conclude the butterflies have either found a closer source of water on the north side of the massif or they have already relocated their colony to a mountain north of Herrada. About five years ago they did the very same thing. If the clear weather persists tomorrow when we visit Rosario we can expect a butterfly blizzard. Warm clear weather stirs butterflies up into a frenzy. There is much movement of the colonies downslope. Many millions fly through the woodlands each day to take water and nectar, and perhaps to exercise their wing muscles in preparation for their return migration to the north. Last Monday a major portion of the loop trail at the El Rosario colony was closed to the public. Many butterflies were down on the trails but the main reason was that many branches had fallen across the trail and blocked the path. The campesinos assured us that the path would be open the following day. Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form