Scientists chase elusive Poweshiek skipperling butterfly

Crunching through waist-high prairie grass, the researchers scan ahead with binoculars. Peering out at the black-eyed susans reaching above the prairie dropseed, they are searching for something they do not expect to find - the endangered Poweshiek skipperling.

This short-lived brown butterfly is winking out of existence across Wisconsin, which, with Michigan and Manitoba, is among the last regions to host what used to be a fairly common species throughout the northern Midwest. Now, it takes more resources just to find the skipperling in its last remaining habitats, and four conservation scientists came out in early July knowing they were more likely to confirm its disappearance than to find this increasingly rare insect.

Asked if he expected to find any Poweshieks that day, U.S. Fish and Wildlife Service endangered species coordinator Phil Delphey said: "To be honest, I don't."

Regardless, he brought two colleagues to join Sharon Fandel, a conservation biologist with the Wisconsin Department of Natural Resources, to survey the Scuppernong Prairie State Natural Area in Kettle Moraine State Forest.

It was nearly too cold and too cloudy for butterflies to be active, but after waiting some time in vain for clouds to clear, the scientists decided to conduct an informal survey. So they marched into the dense prairie in western Waukesha County.

The skipperlings can normally be found feeding on black-eyed susans, which dot the prairie in small clusters. In their adult form, they live briefly, barely two weeks. Then they lay their eggs, often on clumps of prairie dropseed, which are the caterpillar's preferred food source. The Poweshieks go through only a single life cycle each year, making it harder to adapt to changing environments.

The ongoing conversion of prairie habitat to farmland is the prime suspect in the butterfly's continued decline, but the possible list is long: pesticides; climate change; too many prairie burns, or too few.

As the morning wore on, the biologists' optimism was rewarded with brief breaks in the cloud cover that led to a flurry of increased butterfly activity. Dozens of orange great spangled fritillaries fluttered around, barely stopping to rest. Other butterflies were harder to spot, and continued to dampen their flights.

Then Fandel shouted out to the group, "Anyone good at their snakes?"

She had pinned an eastern hognose snake under her clipboard before carefully pinching it behind the head and holding it up for everyone to see. It's harmless, but flattened its head to mimic a cobra in a threatening display.

Andrew Horton of the USFWS spotted a skipper, but it was a more abundant cousin of the Poweshiek, not the day's target.

The butterfly has been on Wisconsin's endangered species list since the late 1980s and was added to the federal list last year. Susan Borkin, an expert on Poweshiek and curator of invertebrates at the Milwaukee Public Museum, said the endangered status does more than just prohibit killing the Poweshiek.

"It allows people to pool resources and expertise and try and focus and understand what's going on," she said. The collaboration between the Fish and Wildlife Service and DNR is part of that.

The U.S. Fish and Wildlife Service is also working with the Minnesota Zoo to try to rear the skipperlings in captivity, with limited success.

The four scientists continued to tread slowly through the prairie as the temperature refused to rise. They occasionally spotted a crescent or sulfur butterfly floating above the compass plants and milkweed. They identified six species in all, but the Poweshiek was nowhere to be found. Perhaps it was too cold for the skipperling to be active; more likely, it no longer lives in this patch of prairi.

This year, 40 skipperlings were counted in a day in a northern Michigan , up from the peak of nine a year ago, giving a glimmer of hope for the disappearing butterfly.

But so far, only three have been found in all of Wisconsin, at the Puchyan Prairie two hours to the north.

At Scuppernong, no Poweshiek skipperling has been seen since 2012. If not found this year, it will be considered extinct at this site.

Even so, the scientists will continue their surveys, just with less intensity, and a little less hope.

©2015 Milwaukee Journal Sentinel
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