August 22, 2014

Butterflies to float through Iowa on annual migration

Saturday is the final day of summer and an annual indicator of fall is the emergence of the year’s last generation of monarch butterflies. Iowa sees many of the earlier generations throughout the summer, but this last batch of orange-and-black butterflies is unique as they undertake a 3,000 mile journey.

Mitchell County naturalist Chelsea Ewin says they’re headed for central Mexico. “Nobody has quite pinned down exactly how the monarchs know when to start traveling but usually the end of August into September is the best time to start looking for them,” Ewin says. It’s a remarkable trip these creatures take, she says, and the migration is still somewhat of a mystery, even to the experts.

“Butterflies that fly south to Mexico will only, next spring, come up to about Texas and complete their life cycle there,” Ewin says. “It will be a couple of generations later that finally make it up to Iowa.” Ewin says the monarch is the only known migrating insect.

In order to learn more about the migration, the Mitchell County Nature Center is helping residents tag monarchs to track their final destination. “If you do find an adult monarch, you can actually put a tag on the butterfly with a special code and then they’ll fly to Mexico and if somebody finds that tagged butterfly, they can trace it back to you here in Iowa,” Ewin says.

The monarch population has taken a hit in recent years. Ewin says tree logging in Mexico as well as the removal of milkweed, the monarch’s main food source, have lead to fewer returning butterflies.

(Reporting by, Angela Barton, KCHA, Charles City)