Monarch butterfly population in decline

Numbers of Monarchs completing annual migration lowest in 2 decades

March 14, 2013

The number of monarch butterflies that are wintering in Mexico after completion of an annual migration has fallen to the lowest level in the last two decades.

Historic wildfires the past few years as well as drought conditions continue to decrease their number. Even worse news: milkweed plants- the only kind they need to survive- are also not in plentiful supply, say a Texas A&M University Monarch watcher.

The World Wildlife Fund, one of the groups that sponsored the butterfly census, blamed climate conditions and agricultural practices that kill off the Monarchs’ main food source, milkweed.

“We are seeing now a trend which more or less started in the last seven to eight years,” Omar Vidal, the head of the wildlife group’s Mexico operations, said in an interview. Although insect populations can fluctuate greatly even in normal conditions, the steady downward drift in the butterfly’s numbers is worrisome, he said.

According to Craig Wilson, a senior research associate in the Center for Mathematics and Science Education and a long time butterfly enthusiast, “It takes four generation of the insects to make it all of the way up to Canada, and because of lack of milkweed along the way, a lot of them just don’t make it.”

The monarchs’ migration is seen as a natural marvel and, for Mexico, a huge tourist attraction. But naturalists regard the butterflies as a forward indicator of the health of the food chain. Fewer butterflies probably mean there are fewer other insects that are food for birds, and fewer birds for larger predators.

“On a recent visit to the Monarch overwintering sites in Michoacan, former President Jimmy Carter said: ‘The Monarch butterfly unites the three countries of North America in peace. It is an ambassador of peace that requires protected areas and ecosystems that are preserved through sustainable agriculture and forestry practices. We need to work together to maintain a healthy and balanced ecosystem for all North America.” Wilson adds.

If people want to help, they can pick up some milkweed plants at local farmer’s cooperative stores, or even scatter the seeds within the pods of the milkweed they see growing wild. This would no doubt be a big boost to help in their migration journey.

Chip Taylor, director of the conservation group Monarch Watch at the University of Kansas notes, “This is one of the world’s great migrations,” he said. “It would be a shame to lose it.”

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