Monarch butterfly population down by as much as 60%

March 31, 2010 After a year of turbulent weather in Mexico and destruction of their habitat, the Monarch butterfly (Danaus plexippus) population could be down by as much as 50% to 60% this year, experts say.

A gathering area for the butterflies northwest of Mexico City was affected particularly hard by severe weather this winter, which killed 50 people in the region. According to Lincoln Brower, a monarch expert with Sweet Briar College in Virginia, "things are in pretty bad shape."

The southbound migration was already the smallest in recorded history, and with the destructive winter, over half of the species' population might have been killed. "This means the numbers going to Texas are going to be down", said Chip Taylor, a professor of entomology at the University of Kansas-Lawrence. He believes it could take years for the Monarchs to repopulate.

Taylor also said that "We’re talking about significant degradation at overwintering sites; the loss of habitat in the United States and Canada and climate change in Mexico. We’ve had three major killing winter storms in the last decade that have never been seen previously. We’re dealing with something new here, and that’s consistent with climate change."

Illegal logging in Mexico and a lack of milkweed in the Midwest United States for the butterflies to lay their eggs in has also taken a toll on the Monarchs' population.