Continental Nomads: Monarch Butterflies

The migration story of monarch butterflies (Danaus plexippus) is an epic adventure that spans generations and thousands of miles.

The route monarchs take for their multi-generation journey. Western monarch populations also make similar, shorter journeys, but populations in the East are the only monarchs in the world known to have an adventure spanning so many generations.

NPS graphic/ S. Sparhawk

The migration cycle of the eastern populations of monarchs are truly amazing trips. Breeding season begins around March, when the first generation leaves for the northern US. Click image to enlarge.

NPS graphic/ S. Sparhawk

A relay race like no other

At the start of the spring breeding season, Eastern populations of monarchs leave their winter habitat in the oyamel fir forests of Mexico to begin a northward journey that may take up to a month and a half to complete. En route, these tiny nomads mate, then lay their eggs on certain types of milkweed plants - leaving it to the next generation to continue another stage of the northbound expedition. During their journey, monarchs live for only two to six weeks. The last generation of a breeding season (which lives for as long as nine months) must then attempt to complete the entire journey in reverse and return to their winter habitat in Mexico.

Check out this journey in selfies!

What about monarchs in the west?

Monarchs in the Western half of US make similar, multi-generation journeys toward the northwest as opposed to the northeast. They occupy overwintering sites along the California coast. Their miles may be shorter, but adventure and national park stop overs are just as epic a migration story!