Little Brown Myotis – State Wildlife Action Plan

The little brown bat is a small insectivorous bat found throughout Oregon in a variety of habitats types. They have variably-colored, long, glossy fur and small eyes and ears. They are similar in appearance to Yuma myotis. These bats are nocturnal and use echolocation to hunt insects such as mosquitoes and moths.

Overview

Species Common Name Little Brown Myotis
Species Scientific Name Myotis lucifugus
State Listing Status Sensitive (pending)

Ecoregions

Blue Mountains

Located in NE Oregon, the Blue Mountains ecoregion is the largest ecoregion in the state. It provides a diverse complex of mountain ranges, valleys, and plateaus that extend beyond Oregon into the states of Idaho and Washington.

Coast Range

Oregon's Coast Range, known for its dramatic scenery, is extremely diverse, with habitats ranging from open sandy dunes to lush forests and from tidepools to headwater streams. It follows the coastline and extends east through coastal forest to the border of the Willamette Valley and Klamath Mountains ecoregions

Columbia Plateau

The Columbia Plateau ecoregion was shaped by cataclysmic floods and large deposits of wind-borne silt and sand earlier in its geological history. It is dominated by a rolling landscape of arid lowlands dissected by several important rivers, and extends from the eastern slopes of the Cascades Mountains, south and east from the Columbia River to the Blue Mountains.

East Cascades

The East Cascade ecoregion extends from the Cascade Mountains' summit east to the warmer, drier high desert and down the length of the state. This ecoregion varies dramatically from its cool, moist border with the West Cascades ecoregion to its dry eastern border, where it meets sagebrush desert landscapes.

Klamath Mountains

The Klamath Mountains ecoregion covers much of southwestern Oregon, including the Klamath Mountains, Siskiyou Mountains, the interior valleys and foothills between these and the Cascade Range, and the Rogue and Umpqua river valleys. Several popular and scenic rivers run through the ecoregion, including the Umpqua, Rogue, Illinois, and Applegate rivers. Historically, this ecoregion is known …

Northern Basin and Range

The Northern Basin and Range ecoregion covers the very large southeastern portion of the state, from Burns south to the Nevada border and from the Christmas Valley east to Idaho. It is largely a high elevation desert-like area dominated by sagebrush communities and habitats.

West Cascades

The West Cascades ecoregion extends from east of the Cascade Mountains summit to the foothills of the Willamette, Umpqua, and Rogue Valleys, and spans the entire length of the state of Oregon. It is largely dominated by conifer forests, moving into alpine parklands and dwarf shrubs at higher elevations.

Willamette Valley

The Willamette Valley ecoregion is bounded on the west by the Coast Range and on the east by the Cascade Range. This long mostly level alluvial plain has some scattered areas of low basalt, and contrasts with productive farmland and large urban areas. It has the fastest-growing human population in the state resulting in challenges due to land-use changes.

Special needs

Little brown myotis occupy a wide range of habitat types and roosting structures, including trees with exfoliating bark, snags, rock crevices/cliffs, caves/mines, wood piles, and even buildings in urban areas.

Limiting factors

Little brown myotis are limited by roosting habitat (large snags) and/or closure/disturbance at hibernacula and maternity colonies. White-nose syndrome has been detected in this species in Washington State. Little brown bats were historically abundant throughout their range, though in recent years populations have declined dramatically in areas of North America where white-nose syndrome is prevalent. Additionally, this species is vulnerable to significant mortality at wind energy facilities. As a long-lived species that can live up to 30 years with low fecundity (adult females typically give birth to a single pup per year), populations do not recover quickly from large scale mortality events.

Data gaps

•Investigate population impacts of wind energy development.
•Hibernating habits in little brown bat populations in western North America may differ substantially from better studied populations in eastern North America that have been heavily impacted by White Nose Syndrome. Additional information on how behavior may be different in Oregon is needed to inform management and models of population trends.
•Investigate the vulnerability of little brown myotis to impacts from contaminants.
•Collect data on annual movement patterns and locations where bats congregate during the breeding season to inform smart siting of wind energy and minimize adverse impacts.

Conservation actions

• Protect known roost sites and reduce disturbance.
• Retain and recruit large snags, cavity trees, and large decadent trees.
• Maintain remnant patches of structurally diverse forest, including large snags, near open water.
• Continue white-nose syndrome surveillance.
• Follow most recent decontamination protocols to prevent spread of the fungus that causes white-nose syndrome, Pseudogymnoascus destructans

Key reference or plan

North American Bat Monitoring Program in the Pacific NW. Read here