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Margined white butterflies are hanging out by Mendenhall Glacier. Here’s why.

Paige Sparks
Margined white butterfly at Mendenhall Glacier on June 17, 2022 in Juneau.

Could you identify a margined white butterfly? Bears, porcupines and eagles get a lot of attention in the summer months, especially from tourists, but rangers at the Mendenhall Glacier Visitor Center say there are some small wonders, too.

“You’ve probably seen them without even knowing what they are. They’re small, little white butterflies that kind of fly around,” said Julia Schostak, an assistant director at the visitor center.

She says the margined white is one of four main kinds of butterflies we’re likely to see around Juneau.

“Sometimes it’s nice to think about the smaller things,” she said. “Our birds and our insects can really kind of open the world past those larger megafauna.”

Margined white butterflies can be found sucking nectar on early summer blooms — or doing a thing called “mudding” or “puddling.”

Schostak says it’s common for butterflies to cool off and drink in moist areas like mud puddles. They take in nutrients from the ground that they can’t get from plants. They know where to land and drink because chemoreceptors in their feet help them sense the composition of the soil.

Schostak says a great place to see this in action is near Nugget Falls, by the Mendenhall Glacier. She says the water there has a perfect chemical composition for the butterflies because of glacier silt in the water.

But don’t step on them!

“Sometimes they just look like little rocks moving,” Schostak said

If you can’t get out to the glacier, don’t worry. Schostak says they’re all over the place this time of year. Look for a white butterfly with some ashy markings on the wings. It’s likely to be a margined white.