Monarch Butterfly Population in Michoacan Doubles Since Last Year, But Threat Continues

The World Wildlife Fund announced this week that the Monarch butterfly population at the overwintering sites in the mountains of Michoacan, Mexico, has doubled in the past 12 months.

The Monarch butterfly sanctuaries are located in the Michoacan mountains about 130 miles west of Mexico City.
An article from the Canadian Press had the most thorough coverage I saw, including an interview with Dr. Lincoln Brower, one of the foremost experts on Monarch butterflies. Brower has devoted himself to Monarch butterfly education and conservation for more than 50 years.
Scientists measure the health of the monarch butterfly population by counting the acres of forest occupied by roosting butterflies.  This year, the area utilized for winter roosting tallied 9.9 acres,  more than double the 4.7 acres of 2010.
Even so, the butterfly rebound is still way less than the almost 20 acres of the 2008-09 winter season and a record 45 acres occupied in 1996-97.  The winter of 2009-2010 was the worst since record-keeping began in 1993.
Flooding, storms and illegal logging in the butterfly sanctuaries, plus destruction of host plant habitat in the United States contribute to the Monarchs’ threatened status. According to the World Wildlife Fund study, two sites that traditionally have seen masses of Monarchs roosting had no butterfly colonies at all this year.
We anxiously await Monarch Watch’s interpretation of the data, anticipated for later this month.

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