Yuma Myotis (Myotis
- Protection Status Notes
- M. yumanensis has neither federal nor state protection designation.
- Myotis yumanensis is a small bat that is usually gray or brown to pale tan dorsally with a paler venter of tan or gray; ears and membranes are frequently pale brown to gray. In some areas M. yumanensis is difficult to distinguish from M. lucifugus and caution is required. Both species are usually associated with permanent sources of water, typically rivers and streams, but Yuma myotis also use tinajas in the arid West.
- Life History
- Yuma myotis occur in a variety of habitats including riparian, and scrublands and deserts, and forests. Mating typically occurs in the fall. Females give birth to one young from mid‑spring to mid‑summer in maternity colonies that may range in size to several thousand; males tend to roost singly in the summer.
The species roosts in bridges, buildings, cliff crevices, caves, mines, and trees.
Individuals become active and forage just after sunset, feeding primarily on aquatic emergent insects. Their diet is known to include caddis flies, midges, small moths and small beetles. After feeding, they periodically rest at night roosts where the food is digested.
- Myotis yumanensis ranges across the western third of North America from British Columbia, Canada, to Baja California and southern Mexico. In the United States, it occurs in all the Pacific coastal states, as far east as western Montana in the north, and as far east as western Oklahoma and Texas in the south.
- Threats and Reasons for Decline
- Yuma myotis may be affected by closure of abandoned mines without adequate surveys, some forest management practices, and disturbance of maternity roosts in caves and buildings. Since this species frequently occurs in anthropogenic structures, it is vulnerable to destructive pest control activities. Some riparian management practices may be detrimental.
- Ongoing Recovery
- Building new bridges to accommodate bats and retrofitting existing structures with bat roosts can provide more roosting spaces. The protection of caves, mines, and abandoned railroad tunnels used by Yuma myotis will contribute to the conservation of this species.
- Information is needed on geographic variation in roosting and foraging requirements. No information known on use and acceptance of bat gates, impacts of grazing and riparian habitat management, winter range, and winter roost requirements.
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