WNS in the West

White-nose Syndrome (WNS) was confirmed in a little brown bat (Myotis lucifugus) found in King County, Washington, in March 2016 – the first recorded occurrence of this devastating bat disease in western North America.

Hikers found a little brown bat on the ground while hiking 30 miles east of Seattle. They safely captured it and delivered it to a local rehabilitator. Sadly, the bat died a few days later. The rehabilitator sent the bat to be tested and our worst fears were confirmed: the bat was infected with the deadly fungus, Pseudogymnoascus destructans (Pd) and had died from White-nose Syndrome.


This new fatality indicated that the fungus and the disease had made a 1,300-mile leap from its previous westernmost detection in Nebraska.

Next Steps: An On-the-Ground Response

Little brown bat (Myotis lucifugus)
Credit: Al Hicks

Effective surveillance for WNS is urgently needed in western regions where bat diversity is high, yet we know relatively little about winter ecology and susceptibility of western bat species to WNS. Winter behavior of western bat species differs from where WNS has previously occurred. Prior to WNS, it was common to find hibernating colonies of tens to hundreds of thousands of bats in eastern North America. In the West, such large colonies rarely exist. Western bats are dispersed across a vast landscape, hibernating in cliffs, rock crevices, talus slopes, caves and mines. This difference in biology requires new approaches to WNS surveillance and bat population monitoring.

BCI is working with state wildlife agencies and the national WNS Disease Surveillance Working Group on strategies to adapt response efforts to these new challenges. A critical knowledge gap is identifying where western bats (particularly Myotis species) spend the winter. Bat Conservation International’s experienced Subterranean Program team members are currently helping our government partners to conduct bat surveys in the region as a part of expanding the national surveillance effort for this deadly fungus. On-the-ground surveillance is critical to knowing how widespread the disease is in the west and in developing appropriate surveillance protocols in the West so we can protect bats that are vulnerable.

Further Reading