Townsend’s big-eared bat is a mammal in the Colorado record. Open occurrence databases hold 193 records for it, most from roost surveys and museum specimens rather than the 19 iNaturalist photographs, fitting for a bat that spends its days deep inside caves and mines.
A bat built for caves
Townsend’s big-eared bat is unmistakable in the hand: enormous ears nearly the length of its body, curled back at rest, over a small brown frame. It roosts in caves, abandoned mines, and rock shelters and hunts moths in the dark, so in Colorado it turns up in the state’s cave and canyon country. Detections gather in the western and northwestern counties, Montezuma and Moffat among them, along with foothill sites near the Front Range in Jefferson County, wherever suitable underground roosts and rock exist.
Roost-bound and easily disturbed
This bat lives its life around its roosts. It gathers in maternity colonies in warm cavities through summer and hibernates in cold, stable caves and mines through winter, and it is famously intolerant of disturbance: a colony that is repeatedly bothered will abandon a roost entirely. Because it hides underground by day, the record is built largely from targeted roost and mist-net surveys, so the sighting pattern tracks fieldwork at known roosts more than any true absence between visits.
A species of concern in Colorado
NatureServe ranks Townsend’s big-eared bat S2, imperiled, in Colorado, a signal that it is vulnerable here even though it is listed G4 globally and least concern by the IUCN. Roost loss, mine closures, and disturbance to hibernating and nursery colonies are the central concerns, which is why its scattered records carry more weight than the raw count suggests.
Full species profile
