The Amazing Monarch Migration

Today we have a guest writer. Tim Eisele, who is a fellow member of both Wild Ones and Wisconsin Conservation Hall of Fame, sent this for me to share with you. Enjoy!

The Amazing Monarch Migration

Simply amazing is the word for the migration of monarch butterflies that moved through Wisconsin in September.

Many people remarked seeing legions of monarchs either roosting in nearby pine trees overnight or floating above flowers in backyards or fields.

Mark and Sue-Foote Martin, co-managers of the Madison Audubon Society’s Goose Pond (Columbia County) did regular counts and saw a high of 1,800 monarchs roosting in the pines overnight on September 9 and 16.

Karen Oberhauser, executive director of the UW-Madison Arboretum and a noted authority on monarchs, said that the monarchs we’ve been watching emerged from a chrysalis several weeks ago and are now migrating to Mexico where they will winter and then begin to migrate back north in the spring.

As they return in the spring, they will mate, lay eggs and die, and their offspring will continue the migration north.

Unlike bird migration, where individuals migrate south to wintering grounds and then back north for breeding areas, the monarch migration is comprised of three or four generations.  In other words, the individual butterfly moving through Wisconsin this fall was the grandchild or great grandchild of the adult that left the wintering areas in Mexico in the spring.

Oberhauser said that what butterflies need are milkweed plants, because that is the only plant that monarch caterpillars will eat, and they therefore lay their eggs on milkweed.

During the summer and fall migration the adults need nectar and they use asters, meadow blazingstar, coneflowers, black-eyed susans, beebalm, and other native flowers (as well as some non-native ones).

“The key is to have plants blooming from May through September,” Oberhauser said.

To see where people are seeing concentrations of monarchs on their way to Mexico, go to Journey North.

And, to attract more monarchs to your property next year, the Wisconsin Monarch Collaborative encourages landowners to plant more milkweed to benefit monarchs.

Thanks, Tim. Nice job!