Monarch Butterfly Migration

October 20, 2000


Provided by: Lincoln Brower, Sweet Briar College
Summary authors & editors: Jim Foster

This photograph of a Monarch Butterfly was taken by Dr. Lincoln Brower, a well-known authority on monarch buterflys. Monarch butterflies, living in the eastern US and Canada, are now winging their way south towards Mexico, where they'll over-winter until about March before embarking on the return journey. Western Monarchs over-winter near the coast in central California. Though they way less than a gram, they'll somehow locate a grove of trees in the highlands of Mexico that they've never visited before. On top of this, their proceeding two generations have also never visited the over-wintering area. The monarchs typically wait for favorable winds before making their journey south. For example, a "high pressure system" located over the midwestern US will bring northerly winds to the eastern states and southeastern Canada. The monarchs will take advantage of winds moving in the same direction they want to go. You may see them as they stop to gather nourishment from milkweed or buddleia (pictured above) as they make their way south.

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