Wyoming’s California myotis story runs through the desert southwest. Sweetwater County, the sagebrush-and-badlands country along the Green River, accounts for most of the state’s records, with a few more from the Bighorn Basin counties to the northeast. That’s the arid Wyoming of rock and rim and dry wash that this little bat favors across the interior West.
The timing stands out: reports bunch from August through October, with nothing from the cold months and little from spring. Late summer into fall is swarming and pre-hibernation season, when bats gather at roost sites and move more than usual, and when bat surveyors work the warm nights. A myotis on the wing in a Wyoming January is possible but unrecorded; a netted one in September is what gets written down.
NatureServe treats the state rank as not applicable here, a sign the species sits at the very edge of its mapped range in Wyoming. With so few records, each from survey-grade work like mist nets or acoustic detectors, the state file can’t yet say whether these bats are a thin resident population or wanderers from stronger populations farther south. The Green River badlands are where the answer would surface first.
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