The Yuma myotis leaves a faint trail in Colorado’s public wildlife records. Open databases hold 134 Colorado records, but none are iNaturalist photos. Museum specimens and acoustic surveys supply nearly the whole picture, which suits a bat that hunts low and fast in the dark.
Tied to open water
Of Colorado’s Myotis, this is the water specialist. It forages in tight, skimming passes just above the calm surface of ponds, slow rivers, and stock tanks, picking off midges and emerging insects almost at the waterline. That dependence pins it to the state’s river drainages: the Yampa and Green country of Moffat County in the northwest, the Purgatoire around Las Animas County in the southeast, and the canyon rivers of Montezuma and Mesa Counties. It roosts by day in cliffs, caves, and under bridges, always within reach of open water.
Summer near the water, then gone
The records bunch tightly into the warm months, when females gather in nursery roosts near reliable water. Then they stop. As the insect supply collapses in autumn the bat drops out of the record entirely, moving to hibernation sites or slipping into torpor to wait out a season with nothing to hunt. The narrow summer window is the whole of when this bat is easy to detect at all.
The most watched of the five
NatureServe ranks the Yuma myotis Vulnerable in Colorado, the most cautious rating among the state’s small brown bats even though the species is globally common. It sits near the edge of its range here and leans on a scarce resource, permanent open water, which makes its Colorado foothold thinner than the raw numbers suggest.
Full species profile
