Learning About the Lives of Pacific Northwest BatsUsing radio-telemetry to study base habitat use requirementsJeffrey TaylorScience InstructorOlympus High School Get Your High School Diploma Online
Bats: Background Information 1000 species of bats world-wide, second to rodents Only group of mammals capable of sustained flight
Bats: Background Information Broken up into two large groups: - Megachiroptera: fruit-eating i.e. “flying foxes” (Old World) - Microchiroptera: small, primarily insect-eating (our bats) * use echolocation to detect prey * use their good night vision to see larger objects and navigate
The Lifestyles of Northwest Bats(Everything is based on energy conservation) Bats have extremely high metabolisms To maintain flight, conduct echolocation, and maintain warmth due to their large surface area
The Lifestyles of Northwest Bats(Everything is based on energy conservation) To conserve energy they sleep… a lot! They hibernate in winter using stored fat
The Lifestyles of Northwest Bats(Everything is based on energy conservation) To conserve energy they sleep… a lot! Enter torpor during the day to conserve fat reserves Only active about 15 min of every night hour
The Lifestyles of Northwest Bats(Everything is based on energy conservation) Because they sleep so much and hibernate, they live much longer than other mammals of similar size. A shrew weighing 5-10 grams lives about 1 year A bat weighing 5-10 grams can live 12-30 years
Myth or Truth? Do bats fly into people’s hair? • Do bats have rabies? • Do bats eat 600 mosquitoes per hour? • Do bats drink blood?
Myth or Truth? Do bats fly into people’s hair? No, bats have excellent vision and sonar • Do bats have rabies? Some do, bats carry rabies around 1-5 per 1000 Less often than raccoons, skunks, or foxes • Do bats eat 600 mosquitoes per hour? • Do bats drink blood?
Myth or Truth? Do bats fly into people’s hair? No, bats have excellent vision and sonar • Do bats have rabies? Rabies is actually rare in bats • Do bats eat 600 mosquitoes per hour? Probably an exaggeration – especially since they roost 45 min per hour digesting food • Do bats drink blood? Only the Vampire bat of Central America
Your Neighborhood Bats Twelve species of bats in the forested regions of the Pacific Northwest Some are very common, while others are rare or endangered There are two species likely to inhabit human dwellings in the PNW (Big Brown Bat and Little Brown Bat).
Little Brown Myotis (Myotis lucifugus) Yuma Myotis (Myotis yumanensis) These two species are difficult to distinguish Most likely bat to be found in buildings Little brown myotis are found across North America Yuma Myotis are found only west of the Rockies
Big Brown Bat(Eptesicus fuscus) A very common bat that ranges across North America Weighs about the same as a mouse (20-30 grams) Known to occupy buildings and will bite if handled
Foliage Roosting Bats Migrate south for the winter Silver-haired Bat(Lasionycteris noctivagans) Found across northern North AmericaLittle is known about its population status Hoary bat (Lasiurus cinerus) The largest bat in North America Largest range: All North America & Hawaii
Townsend’s Big-eared Bat(Plecotus townsendii) A rare cave roosting batHuge ears used to detect low-frequency moths Probably the most endangered bat in Washington
California Myotis(Myotis californicus) A very small somewhat common bat More common eastside of the CascadesOften found in rock crevasses Western Small-footed Myotis (Myotis ciliolabrum) The smallest bat of Northwest forests More common eastside of the Cascades Found in rock crevasses and some caves
Western Long-eared Myotis(Myotis evotis) A common bat found in forests west of the Rockies Uses peeling bark of snags as roost sites
Fringed Myotis(Myotis thysanodes) A rare bat, uses caves and rock crevasses for roosting Species of concern because population status is unknown Distinguished by the fringe of hair on the tail membrane
Keen’s Myotis(Myotis keenii) A cave roosting species found in coastal spruce forests Endangered in Canada, status is unknown in the U.S.Smallest range of any North American bat
Long-legged Myotis(Myotis volans) An uncommon bat of the montane forests It is the largest of the Myotis bats in the Northwest It roosts under the peeling bark of snags
Control Methods for Bats in Your Homes There are ways to exclude bats without killing them: • Hire pest management company to close off the access points Some bats love attics for roosting or hibernating due to the warmer temperatures. So, you may want to seal off the vents
Control Methods for Bats in Your Homes There are ways to exclude bats without killing them: Between November and March is the best time If the bats are hibernating elsewhere, then when they return in spring, they can not get into your house.
Control Methods for Bats in Your Homes There are ways to exclude bats without killing them: If you do exclude them in the summer, wait until at least Augustafter the young have fledged Otherwise the mothers will not be able to get back to them to feed them.
Control Methods for Bats in Your Homes There are ways to exclude bats without killing them: NEVER exclude them in the day! Wait until they have emerged for the night. Otherwise you will have an attic full of desperate bats that will starve to death.
How do we Conserve Bat Populations? Bats are very important to the ecology and economy of many ecosystems. They feed on many insects that cause great damage to forests, agricultural crops, and people.
Understanding the Ecology of Bats in Pacific Northwest Forests
Habitat Fragmentation is Considered the Biggest Threat to Bat Populations
My Job Learn about the ecology of bats in the forests of the Cascade range. Find out what habitat types and ecological features are important to bats. Determine and make recommendations for timber management practices with bats in mind.
The Long-legged Myotis • The long-legged myotis is generally considered to be associated with late-successional forests Listed by the Northwest Forest Plan as a species of concern and in need of further study Concerns that populations of this and other Myotis species were declining in the Northwest
Information Needs for Myotis volans What are the specific roost-site structures preferred by the long-legged myotis? What is habitat use compared to availability? I.e. what successional stages do they prefer? Will the long-legged myotis use retention implemented under the Northwest Forest Plan?
Alien Abduction! Your on your way to get a drink Then boom, you caught in a giant net, bright lights shine upon you, giant hands handle you. Then…
Alien Abduction! Take Measurements and Place Radio-transmitters on Their Backs
Unexpected Results and More Questions My hypothesis was that they were roosting in the cave in the day and would head out at dusk Instead, I captured them going INTO the caves at dusk! But why?
#2- Release them and track them to their day-roost locations the next morning.
They were roosting in trees in the day! As it turns out, they were using the caves to get a drink after they woke up and before they’d head out to hunt for moths.
#3- Take roost measurements including: Roost height, diameter, canopy cover, canopy height, snag class and snag species
Analysis GPS each roost-site location Create a circle with a radius from the water source to the furthest roost-site Use a GIS and aerial photos to map roost-sites and available habitat Place habitat polygons into circles Use a computer program to determine habitat use versus availability
Eight habitat types were delineated Douglas fir/grand fir forests Stem initiation Earliest Succession Stage
Early Successional Retention Types Aggregate Retention Patch Shelterwood
Mid-successionalStages Stem Exclusion Stem Initiation Small Young trees are so densely packed that no new sprouts can grow Some of the young trees die, allowing more light to hit the ground and more new seedlings can survive
Late-SuccessionalStages Stem Reinitiation Medium Stem Reinitiation Large
Conclusions Long-legged myotis use snags as day-roosts Prefers late-successionalforests Strongly prefers large grand fir snags
Conclusions Avoid early successional stages, but occasionally use aggregate retention patches and shelterwoods. Unknown what effect lack of late-successionalstands has on population size or reproductive success
What can you do to protect bat populations? • Leave dead or dying trees on your property • Place a bat box on any large trees about 20 feet high • Avoid using insecticides, bats can be poisoned • If you find bats in buildings other than your homes, such as barns and sheds, let them stay! • If you have bats in your attic, leave them if they are not causing problems
Management Implications Leave snags for bat species Leave at least small patches of late-successional forests in managed forests Grand fir should be maintained in management prescriptions for wildlife