Temperatures are getting cooler, and winter is on its way. That means monarch butterflies are making their way through Oklahoma on their way to Mexico for the winter. If you think you’re seeing fewer of them each year, you aren’t alone.
Every year tens of thousands of monarch butterflies over much of the United States take to the skies and make their journey south to Mexico.
Stephanie Jordan is the pollinator outreach coordinator for the Nature Conservancy of Oklahoma. She says fall migration peaks in late September and early October.
"They’ve been passing through Oklahoma for quite a few weeks now and they will be migrating through for two to three more weeks. So you can see large numbers kind of depending on what's going on with the weather and wind patterns," says Jordan.
"Sometimes you can go outside and just see several flying by if you’re really lucky. You might find them roosting in a tree, or you might know where they are roosting in a tree and get to go see them. That happened to me last week. They were roosting in the Fall Cypress trees at the Myriad Gardens. I heard about it and I went down before the sun was up and I caught a roost of about 2,000 monarchs in the trees where you could just walk underneath them and it was so magical. Those numbers used to be common 30 years ago but unfortunately they aren’t now.
Jordan says there are several contributing factors to the monarch's decline.
"Some of it has to do with loss of habitat, herbicides and pesticides. You wouldn’t think that herbicides as hurting monarchs, or hurting bugs in general. There are herbicides that our crops can tolerate that get rid of a lot of habitat for wildlife," she says. "The monarch butterfly has to have milkweed to lay eggs on and raise their young. The baby monarchs - the caterpillars - will eat the milkweed and develop a toxicity that gives them protection later in their life when they are a butterfly. So that’s the only plant that they have adapted to eat and, unfortunately, a whole lot of that has gone away.
Researchers suggest that climate change could also be contributing to the population decline.
"We’re seeing some issues with climate change that we suspect are changing how their hormones operate in their brain. The last generation monarchs - the one that migrates and overwinters in Mexico - is born sexually immature and that’s important because monarchs can either mate or migrate, but they really don’t have the energy to do both. So, these hormones in their head keep them at that balance where they are not sexually mature yet, and if we have too many warm days it seems to be contributing to those hormones shifting and their priorities shift and they get confused about what their job needs to be."
Monarchs also have a relatively short lifespan. The butterflies you see right now flying south are not the same ones that will be coming back up in the spring. Jordan says it's
three generations from Mexico to Canada and one to two back.
"The last generation that’s born they are the travelers and they are actually a fairly different butterfly. They are much bigger. They are much darker and, like I said, they are sexually immature."
As monarchs continue their journey south into Mexico there are a few things Oklahomans can do to help.
"In this part of the migration they go up I-35, so the closer you are to I-35 the more important it is for you to be mindful of things that you can do to help, and also mindful of the things you can do to harm," said Jordan. "A lot of people are looking for the convenience of getting rid of mosquitos in their yard and not realizing that when they use a more broad spectrum pesticide like that that can harm migrating monarchs that might stop by your yard for a rest or stop by your neighboring flowers that that pesticide has blown on to."
Jordan suggests waiting a few weeks to let the migration pass before attempting to apply pesticides so the butterflies have a safer environment.
More information about monarchs, the migration and how to create a suitable habitat in your yard can be found at Okies For Monarchs.
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