Is migration the reason for monarchs’ decline?

Why are monarch butterflies on the decline? “The migration itself might be the problem,” researcher Anurag Agrawal told the Washington Post. Agrawal is lead author on a paper in Science analyzing the threats that butterflies face as they migrate between Mexico and the United States. The authors found the greatest decline of monarchs appears to occur in Mexico and during migration north.

Read more in the Washington Post, or read the study here.