A monarch butterfly visits the Discovery Center.

If you see a Monarch Butterfly in the pollinator gardens at the Discovery Center this month, know that they are fattening up for quite a journey. These amazing creatures rely on a migration pathway that stretches from southern Canada to the mountains of Mexico. Butterflies that hatch in the summer have a brief life span of a few weeks, but those that emerge in late August or early September are different. They make the long journey to central Mexico, stay alive all winter, then migrate back north in the spring. 

During the past two decades, there has been a drastic decline in the number of monarchs in the U.S. and those that are wintering in Mexico (somewhere between 80-90%). The culprit could be a loss of breeding habitat in the U.S. and Canada, loss of wintering habitat in Mexico, a lack of food sources for migrating butterflies or a combination of factors including natural diseases or pests. 

One thing that we can do in N.H. is make sure that we have enough of their preferred food: milkweed. Many butterflies have a single plant that is key to the survival of the larval stage—this is called the host plant. Milkweed is the host plant for monarch butterflies, and it is critical because it provides the toxin that makes the adult butterflies poisonous.

The beautiful coloring of a monarch is a serious warning to predators—that they contain a chemical compound that goes straight to the heart to most vertebrates. Even the other pollinator plants that provide food for larval and adult monarchs are often co-located with milkweed. Plant a pollinator garden this fall or spring  and help launch one of the most impressive migrations in the natural world.