Iron County, in Wisconsin’s far north woods, holds more than half of the state’s mapped northern myotis reports. The rest scatter through the Driftless Area and the central counties, with Richland County a distant second. The most striking feature is the September spike: reports that month outnumber the rest of the year combined, which points to fall surveys at hibernation sites rather than a sudden flush of bats. Records follow the people holding the nets.
The last mapped report dates to May 2017, a sobering detail for a bat the IUCN lists as Near Threatened and NatureServe ranks as imperiled worldwide. Wisconsin’s own rank is S1, critically imperiled. Since white-nose syndrome reached the state’s caves and mines, northern myotis numbers have fallen hard across the Upper Midwest, and a quiet recent record fits that collapse better than it fits a hidden surplus.
What the older records still say clearly is where the bat did well: big, unbroken northern hardwood and hemlock forest near the lakes and bogs of the Northwoods, with underground winter quarters close enough to reach each fall.
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