“Butterflies Over San Marcos” written over a picture of bobcat/ butterfly mural near Texas State’s agriculture building

Butterflies over San Marcos

By Rachael Gerron
Web Content Contributor

You may have noticed over the past few weeks that brown butterflies have been following you to class, or you may have even found some stuck to your car’s windshield. This is due to a migration of American Snout Butterflies frequently seen in Central and South Texas.

Being from North Texas, I’m not used to seeing a butterfly migration in the fall, and I wanted to learn more. A Texas State biology professor pointed me to a study done by Professor Lary Gilbert at the University of Texas at Austin in the 1970s.

Gilbert’s research found that snouts don’t have predictable migration patterns like other butterflies, so if you’ve never noticed them in San Marcos before this fall, that is why. When snouts migrate, they come out in swarms between late June to mid-October, which we saw here in San Marcos this fall.

“It used to happen every eight years or so,” Gilbert said. “Now we’re seeing this pattern every two, three years.”

Photo of snout butterfly on the window
Caption Snouts are named after their distinct anteater- like noses. Image by Destiny Pearson.

Snouts lay their eggs on hackberry tree leaves, found in Central and South Texas. Snout butterflies also commonly appear after a period of heavy rain, following a long drought. Both of these factors make this area of Texas a perfect environment for these butterflies to migrate.

In case you missed them, here’s a montage of the snouts flying over Texas State this fall.

Featured image by Rachael Gerron.

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