Visiting the Monarch Sanctuary with Dr. Lincoln Brower January 13, 2006 My research team and I arrived on the "Llanos de los Tres Gobernores" at noon. This is a very large open field located at about 10,100 feet elevation at the upper base of an extremely beautiful mountain known as Cerro Pelon. Cerro Pelon is in the core zone of Monarch Butterfly Biosphere Reserve, and has been used by monarch butterflies as prime overwintering habitat nearly every year since the late 1970's. On this lovely sunny day, our first sight was of thousands of monarchs drinking water from a muddy area on the east side of the Llanos. Looking up, we saw a multitude of butterflies flying eastwards about 15 feet over the ground across the Llanos in search of places to drink. Westwards, the swarming monarchs were so thick that they formed a golden veil in front of the forest in the background from which they were emerging. We soon realized that were two rivers of monarchs, one flying out of the colony towards a distant water source, and a second flying higher up and back into the colony. As we walked through the veil into the forest, we encountered the top of the colony at the head of the valley where water breaks out as a spring, known locally as the “Ojo de Agua." The boughs and trunks of hundreds of Oyamel firs and cedars were draped with curtains of monarchs resting quietly in the shade. The colony was moderately sized; it contained perhaps as many as 25 million monarchs and occupied about an acre of the trees.   Copyright 2006 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form