Woodland Fish & Wildlife • 2019 Bats and Small Woodlands Authors: Ken Bevis, Washington Department of Natural Resources, Barbara Garcia, United States Forest Service, Susan Barnes, Oregon Department of Fish and Wildlife, and Eliana Pool, Cafferata Consulting. Introduction of insects too, but they mostly work the plant productivity. Note: Though some day shift. Many insects only come out bats are pollinators, we don’t have any Bats are small flying mammals that come at night (think moths). Nocturnal bats, bats in Oregon and Washington that are out at night, emerging from crevices in therefore, are the primary predator of considered pollinators. rocks, trees, caves, bridges and build- numerous forest damaging species such Globally, bats are the second most di- ings with the ability to fly in complete as defoliating moths and cambium eat- darkness! Bats are a remarkably diverse verse mammalian species group (Order ing beetles. All of the bat species in Or- Chiroptera – behind Rodentia), with and wide spread species group, with egon and Washington are insectivorous important ecological roles. approximately 1,300 species worldwide (eat insects). Bats also assist in nutrient (www.batcon.org). Specific information Bats have enormously important, and cycling by widely distributing droppings on bats in Oregon and Washington is generally unseen, ecological roles. In (guano). Bat guano is rich in nutrients, found in Table 1. Note that at the time the Pacific Northwest, bats are best phosphorous and nitrogen in particular, of this publication, the Keen’s myotis known for providing insect control. A which are important for tree growth and status as a separate species is under nursing little brown bat can consume review. Oregon and Washington pro- Canyon bat her weight in insects in a single night vide a wide array of habitats supporting (WDFW, Living with Wildlife), which ecosystems where bats thrive. In general calculates out to about 2,800 mosquitos bats use a variety of habitats both natu- per bat, per night! Colonies, typical ral and human constructed. of the Pacific Northwest, may contain many hundreds, or even thousands, This publication will help small wood- of bats. It is estimated that the pest land owners understand which bats live control services provided by bats save in Oregon and Washington forests, what farmers more than $3 billion annually. role these bats play, and their impor- A single bat colony can thus consume tance to forest ecosystems. We will ad- large numbers of insects that would dress threats to bats, how bats support otherwise damage or consume valuable forest ecosystem health, and how small plants, such as food sources or trees, or woodland owners can help promote bat bite us. Birds consume vast numbers Parastrellus hesperus habitat, and therefore, bat populations. Townsend big-eared bat Little brown bat Spotted bat Corynorhinus townsendii. Photo by Myotis lucifugus. Photo by Shawn Thomas Euderma maculatum Eliana Pool 1 Woodland Fish & Wildlife • 2019 Species Range Habitat Requirements Uses a variety of habitats ranging from forest to urban. Commonly found around water sources, Myotis Throughout in both hardwood and conifer forests, and using structures such as buildings, mines, and Little brown bat lucifugus OR/WA bridges. Large diameter snags (>16”) and trees with sloughing bark are important habitat com- ponents. Uses a variety of habitats usually in close proximity to a water source including hardwood and Myotis Throughout Yuma bat conifer forests, grasslands, shrub-steppe and deserts. Large diameter snags (>16”) and trees with yumanensis OR/WA sloughing bark are important habitat components. Long-eared Myotis Throughout Commonly uses rock outcrops and large diameter snags (>16”) within dense conifer forests. myotis evotis OR/WA Long-legged Myotis Throughout Found in conifer forests, deserts, dry rangelands and riparian areas. Large diameter snags (>16”) myotis volans OR/WA and trees with sloughing bark are important habitat components. Inhabits dry forests, shrub-steppe, arid-grasslands and deserts as well as coastal hardwood California Myotis Throughout and conifer forests, meadows, and riparian zones. Large diameter snags (>16”) and trees with myotis californicus OR/WA sloughing bark are important habitat components. Western Inhabits dry climates in conifer forests, deserts, shrublands, riparian areas and grasslands in Myotis East of Cascades small-footed relative proximity to rock features such as caves and cliffs. Large diameter snags (>16”) and trees ciliolabrum in OR and WA myotis with sloughing bark are important habitat components. Coastal WA Myotis Restricted to lower elevation coastal conifer forests where large trees, large diameter snags Keen's myotis (not found keenii (>16”), rock crevices and caves are present. in OR) Myotis Throughout Found in dry forests throughout the PNW utilizing large diameter snags (>16”), rock crevices, Fringed myotis thysanodes OR/WA caves, mines, buildings, bridges and green trees often near water. In western Oregon species is often associated with coniferous and deciduous forests. Utilizes Eptesicus Throughout areas above tree canopy, streams, canyons, and in forest transition areas such as along roads, in Big brown bat fuscus OR/WA clearings and along the forest edge to hunt. Also found in buildings, mines, and under bridges. Large diameter snags (>16”) and trees with sloughing bark are important habitat components. East of Cascades Antrozous Inhabits dry forests open oak and ponderosa and farmland. Also utilizes live trees, large diameter Pallid bat in OR/WA and in pallidus snags (>16”), rock crevices, mines, buildings, and bridges. SW OR Found in dry climates and areas where tall cliffs exist, open pine forests, and in conifer and aspen Euderma East of the Cas- Spotted bat forests. Utilizes riparian zones and meadows for foraging. Large diameter snags (>16”) and trees maculatum cades in OR/WA with sloughing bark are important habitat components. Corynorhi- Inhabits coastal and dry conifer forests, grasslands, and deserts; using caves, bridges, mines, Townsend's Throughout nus buildings, hollow trees, marshes, streams and riparian areas. Large diameter snags (>16”) and big-eared bat OR/WA townsendii trees with sloughing bark are important habitat components. Lasiurus Throughout Found at high elevations throughout a variety of habitats. Large diameter trees (>16”) with Hoary bat cinereus OR/WA sloughing bark are important habitat components. East of Cascades Parastrellus Found in lowland arid environments, especially deep canyons and in other rocky areas. Large Canyon Bat in OR and in hesperus diameter snags (>16”) and trees with sloughing bark are also important adjacent to these areas. SE WA Lasionycteris Throughout Occurs in structurally complex forest environments and associated riparian zones. Large Silver-haired bat noctivagans OR/WA diameter snags (>16”) and trees with sloughing bark are important habitat components. Southern OR Range extends as far north as Roseburg, OR. Species does not tend to hibernate, usually Brazilian Tadarida (not found seeking out sources of warmth during cold months. Uses hollow trees, caves, bridges, and free-tailed bat brasiliensis in WA) buildings. Large diameter snags (>16”) and trees with sloughing bark may also be important. 2 Woodland Fish & Wildlife • 2019 Bat Biology Day roosting Hoary bat Bats are nocturnal mammals with sur- Natural day roost sites include cracks prisingly long life spans and slow repro- and cavities in snags, under loose bark, ductive rates given their small size. Once hollow trees, caves and rock crevices. they make it through the juvenile stage, Manmade roosts are plentiful, such as bats are thought to usually live for 10 to under bridges, attics, under roofing, 20 years, and generally have only one or abandoned buildings and under shut- two young per year (BatCon.org). ters or eaves of buildings. During the day bats may experience a resting state Echolocation known as torpor, though sometimes Bats use echolocation to catch food. To they are observed foraging and drinking echolocate, bats send out sound waves water during the day or low light levels. from the mouth or nose. When the sound Essentially, torpor is a state of decreased waves hit an object, they produce echoes. physiological activity, usually by a re- The echo bounces off the object and returns duced body temperature and metabolic Aeorestes cinereus. Photo from USFS to the bats’ ears, allowing them to locate rate and is a period of time wherein the the position of the prey. They are the only bat roosts in order to conserve energy. torpor and has additional associations mammal that hunts at night while flying. Bats also utilize torpor during food with day length and hormone changes. shortages and bad weather. For some Many bat species found in Oregon and Nursery sites species they do this in medium-large Washington are known to hibernate, or Nursery sites, otherwise known as groups, for others this is a solitary go into a low-energy sleep state for an maternity colonies, are only occupied activity. It is important to note that day extended period of time during winter by breeding females and their young. roosting bats are easily disturbed, which months. This enables bats to survive Nursery sites are usually well protected, can be detrimental because this causes a periods of reduced food availability and disturbance free environments such as bat’s metabolic rate and body tempera- temperatures. During this time, bats tree crevices or