Endangered Oregon Butterfly Makes a Comeback

The Institute for Applied Ecology, a Corvallis-based nonprofit, reports that the endangered Fender’s blue butterfly has almost doubled in number since 2017.  

Fender’s blue is native to the Willamette Valley, with 15 known population groups across enton, Lane, Linn, Polk, Washington, and Yamhill Counties. It is named after entomologist Kenneth Fender and the striking blue-black wings exhibited by the male of the species. The butterfly was thought to have gone extinct in 1937, until it was rediscovered in 1989. It was given endangered statues in 2000, due to the loss of its prairie habitat to agriculture, fire and invasive plant species.  

Furthermore, Fender’s blue is dependent on the plant Kincaid’s Lupine, itself a threatened species, as a host for their eggs.  

With funding from the U.S. Fish and Wildlife Service, IAE has been monitoring the Fender’s blue population since 2016. Their first annual survey estimated 29,000 butterflies in the valley, a far cry from the roughly 3,000 thought to exist in 1993.   

However, after a rugged winter the population dropped to 13,100 in 2017, 2018 wasn’t much better, seeing an increase of only 600 butterflies.  

2019, on the other hand, saw a resurgence in the species, with an estimated 24,500 butterflies. IAE attributes this to the success of habitat restoration by organizations including the Army Corps of Engineers, USFWS National Wildlife Refuges, the USFWS Oregon Fish and Wildlife Office, the Bureau of Land Management and Bureau of Reclamation, Benton County, The Nature Conservancy, Greenbelt Land Trust, and Yamhill Soil and Water Conservation District.  

By Brandon Urey