Monarch Butterfly Migration Update: October 22, 2004
A Million Monarchs Fill the Sky
Over the weekend, Dr. Bill Calvert was traveling with a film crew in northern Mexico. He witnessed what was perhaps the most spectacular migration of his lifetime.
"There were a million butterflies in the air," he exclaimed. "It was just absolutely phenomenal. The sky was pure butterfly! Here are some pictures, courtesy of photographer Jonathan Dueck. But they just don't do it justice. They miss the layer upon layer of butterfly as you refocus your binoculars. They miss the whole sky full! The densities were just stupendous, they were just absolutely astounding. Seeing a million butterflies passing over is kind of magical."
Mountain Geography Focuses the Migration
The crew was filming the monarch migration in a unique part of the Sierra Madres Mountains which Dr. Calvert calls "butterfly junction."
"There’s something about that mountainous area there, where the mountains turn from an easterly direction to a southeasterly--or a south, south easterly--direction that focuses the monarch migration."
At Monterrey, the mountain range changes directions and the butterflies follow that bend. (See picture.) "It was very curious traveling toward the mountains. We weren’t seeing that many," he explained. But once they reached the sweet spot, a million monarchs appeared as if on command.
How Much Longer is the Journey? Challenge Question #11
The millions of monarchs Dr. Calvert and crew saw last weekend were at latitude 25 N. The winter sanctuaries are at latitude 19 N. How much farther must those monarchs fly?
Noticias del avance de la migración en México
Special thanks to Rocio Trevino of Correo Real for these special Spanish reports from northern Mexico about the migration there:
Discussion of Challenge #10: How Many Mexican States?
As the migration moved into Mexico last week we asked, "How many states does Mexico have, and which ones will the monarchs pass through?" The answer came from Mexico:
here is Arturo's list of the states monarchs will cross:
Following the Migration Pathway through Northern Mexico
This stunning NASA image gives a butterfly’s view of the migration route through Mexico. Read Dr. Calvert’s description of the main migration pathway. The towns, states and major geographic features are in bold text. Can you follow the monarch's route? Which states does Dr. Calvert name?
Watching and Waiting at the Over-wintering Sanctuaries
Not a single monarch in sight, reports Estela Romero from the monarch's finish line deep in central Mexico. Residents there who depend on tourism are worried about reports of a small monarch population this year. Only half as many tourists visited last year, they say. Are concerns about deforestation too little too late, wonders Estela.
This Week's Migration Maps
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The Next Monarch Migration Update Will Be Posted on October 29, 2004.
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