Migrating Insects with Jim McCormac

Find Their Way Back Home

I noticed around September 15 that the male ruby-throated hummingbird stopped visiting my feeder. An olive green female hung around for a little while longer, but soon, she was gone as well: They’ve migrated. How do they know when to go? And how do the butterflies that travel know when and where to go? For example, Monarch butterflies make an incredibly long trip to Mexico where they hang out in trees, which are virtually dripping with tens of thousands of the orange and black insects huddling to stay warm. What guides these insects to their winter home?

This week’s guest Jim McCormac, who works for the Ohio Division of Wildlife, shares some science on migration. Jim noticed this year that moth and butterfly populations were way up in his area, especially for the Buckeye butterfly (above, photo by Jim McCormac).

We talk about co-evolution and how important it is to have larval plants for caterpillars that are so necessary for providing food for baby birds. I complained that the local birds do not eat gypsy moths and Japanese beetles. Jim says that is an example of how the birds favor the insects they evolved along with, and may not have developed a taste for the imported crawlers. But he says that wheel bugs (left, photo by Jim McCormac) do attack the beetles, and shares that story.

Of course the most miraculous migration story in our country is the tale of the familiar monarch butterflies (right, photo by Jim McCormac). The monarchs do travel thousands of miles, but the ones we see are not necessarily the ones that come up from Mexico: successions of generations make the trip. How do they find their way to Mexico? Listen to the show to hear the rest of the story.

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