First-ever releases of endangered Poweshiek skipperling!
August 27, 2018
Poweshiek skipperling pupae. Photo by Carrie Tansy/USFWS.
We at the U.S. Fish and Wildlife Service have reached a milestone in our efforts to prevent the extinction of the Poweshiek skipperling, an endangered prairie butterfly. In June, the Minnesota Zoo successfully released two captive-reared Poweshiek skipperling butterflies at a prairie fen site in Oakland County, Michigan. The release is the culmination of a multi-year, international conservation effort to save this highly endangered species. Just days prior to the Michigan release, another recovery partner, the Assiniboine Park Zoo, successfully released six captive-reared Poweshiek skipperlings in southeastern Manitoba. It is estimated that only about 500 Poweshiek skipperlings remain worldwide, which means that the addition of these eight butterflies is especially significant. The Manitoba release was the world’s first release of captive-reared Poweshiek skipperlings, while the Michigan effort marks the first-ever release in the United States.
Raising this species in captivity posed several challenges, but we and our partners have learned a great deal over the past two years. Both the Assiniboine Park Zoo and the Minnesota Zoo have built capacity by developing specialized equipment to simulate wild conditions and increase survivorship. In future years, scientists hope that we will be able to augment the existing populations with more captive-reared adults. This is expected to boost the existing populations because butterflies that are reared in controlled settings (for example, without predators) are expected to have a higher rate of survival than their wild counterparts. Eventually, with more captive-rearing success, we and our partners will consider reintroductions of the species to historically occupied areas.
Other species have benefited from husbandry research, capacity-building and the collaborative partnerships that have resulted from this project. For example, the husbandry research we have conducted for Poweshiek skipperling has also benefited the federally threatened Dakota skipper, which was successfully reintroduced to a historical location by the Minnesota Zoo and partners in 2017. Simultaneous to the Poweshiek skipperling captive rearing effort, we and our partners are researching the cause of the species’ decline and conducting active habitat management at its sites. These efforts, too, can help other species inhabiting those locations.
Along with the Minnesota Zoo, Assiniboine Park Zoo, and the Service, this international partnership includes the Michigan Natural Features Inventory, Springfield Township (Michigan), Michigan Nature Association, North Oakland County Land Conservancy, The Nature Conservancy of Canada, University of Winnipeg, Michigan Department of Natural Resources, Wisconsin Department of Natural Resources, Minnesota Department of Natural Resources, The Nature Conservancy, New College of Florida, Central Michigan University, Minot State University, Milwaukee Public Museum, The Conservation Fund, Toledo Zoo, private landowners and independent researchers.
A female Poweshiek skipperling is placed on a flower following egg collection. Photo by Vince Cavalieri/USFWS.