Photo: Courtesy of Lincoln P. Brower, Sweet Briar College
 FIGHTING FOR SURVIVAL: Overwintering monarch butterflies on the ground after a snow and rain storm in the Sierra Chincua, January 20, 1983. Many of these survived because the temperature didn't plunge below freezing following the storm.

Across my dreams with nets of wonder
I chase the bright elusive butterfly of love

--Bob Lind

Jan. 11, 2002 started a bad weekend for monarch butterflies. Late that night, an unusually powerful storm invaded the butterflies' overwintering grounds in the Oyamel fir forests west of Mexico City, which are normally dry at that time of the year. According to Monarch Watch at the University of Kansas in Lawrence, the butterflies "form dense clusters on the trees, with densities of 10 million or more butterflies per hectare," distributed over several different colonies. That can add up to 100-500 million butterflies south of the US border....

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