
MEXICO CITY – The number of monarch butterflies expected to fly into Mexico during their 2011-2012 migration will be greater than in the two previous seasons, since “a partial recovery” in the number of the species’ colonies is anticipated, an environmental group said.
Millions of the large orange butterflies flee the cold Canadian fall and winter to find refuge in the forests of pine and oyamel fir trees in the Monarch Butterfly Biosphere Reserve located in the western part of Mexico state, which surrounds the Federal District and forms part of the Mexico City metropolitan area.
In the migratory season of 2008-2009, the area occupied by their colonies clustered in the evergreens was 5.6 hectares (14 acres), while in 2009-2010 it dropped to 1.92 hectares (5 acres) due to bad weather conditions.
Mexican officials and various environmental groups presented on Monday the results of a study indicating that during the current 2010-2011 season, which will end in March, the butterflies are covering an area of 4 hectares (10 acres), more than double the 1.92 hectares (5 acres) registered the previous year.
The report shows that monarch butterflies migrating from the United States and Canada currently occupy a woodland area in western Mexico that is more than double that of the previous year, the World Wildlife Fund, or WWF, said in a press conference.
“The numbers are still below average,” however, the director of the WWF’s Mexico Program, Omar Vidal, said.
The monarchs (danaus plexippus) begin migrating in early October from southern Canada, cross the United States at a speed of 120 kilometers (75 miles) per day, to arrive the second week of November at their Mexican “winter home,” located in the woods of Michoacan.
They settle in for five months, their time for mating and reproduction.
In March they take off again on their return journey north.
The Monarch Butterfly Biosphere Reserve, located between the states of Mexico and Michoacan, does not measure migrations in numbers of the insects but in the hectares (acres) of woodland they occupy upon arrival. EFE