Field Notes from Mexico Contributed by Dr. Bill Calvert March 21, 2001 Dr. Bill Calvert All last week butterflies from the Rosario colony flooded the town of Angangueo. Thousands were in the air, all proceeding northward. People in Angangueo certainly notice when the monarchs descend into town en masse. When they're in town, that's a pretty good indication of remigration occurring. It's too far for the butterflies to go back to the sanctuaries--so it's virtually certain that they're ready to head north. The same was undoubtedly occurring to the north of the Chincua colony, but since access is from the east, we did not observe it. It was very obvious that the butterflies were leaving to breed. Multiple mating could be seen at any given time within the colonies. And both the Chincua and Rosario colonies were reduced somewhat from the size they were the week before. As we approached the Chincua colony, the tempo of butterfly activity increased noticeably. Monarchs were flying everywhere, many were basking suddenly on their clusters and at other, more exposed positions on the trees. Several cascading events were witnessed. This is when a cluster disintegrates lake water pouring out of a jug. The butterflies all fly off in the same direction creating a spectacularly beautiful sight. The purpose of this behavior is still not know, but it may simply be a manifestation of colony breakup. This is the time of the year when the tropical sun beams in on Mexico's Transvolcanic Belt. The forests appear to be lazy and warm -and also dry. Flowers are blooming everywhere. Monarchs are seen floating through the understory, some stopping for a sip of nectar, others just flying along with no apparent purpose. The forest are filled with bird sounds. Most prevalent are the soft chatterings of the Slate-throated-red-starts, although other warblers are also calling. This year we missed the Mountain trogon whose distinctive plaintive cooing can usually be heard this time of the year. But we saw the raucous chattering gray barred wrens, always a rare treat. It was a remarkable year. Bill Calvert (now back home in Austin, Texas!) Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form