Difference between revisions of "Bat Species of California's Central Coast Region"

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(Importance of Bat Species to California's Central Coast Region)
(Bat Species of California's Central Coast Region)
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|Western red bat
|Western red bat
|trees, shrubs; occasionally caves
|trees, shrubs; occasionally caves
|Unknown (hypothesized to be a hibernator)  
|Unknown (hypothesized to be a migratory)  

Latest revision as of 15:06, 20 April 2020

An environmental summary created by the ENVS 560/L Watershed Systems class at CSUMB.

This page summarizes the distribution, habitat, life histories, and conservation status of bat species within California's Central Coast Region.

Importance of Bat Species to California's Central Coast Region

In addition to the intrinsic importance of bat species to global biodiversity, bats provide several key ecosystem services.

Pest Control in Agriculture

All bat species in the California Central Coast Region are insectivores and primary predators of beetles, moths, leafhoppers, and other insects that cost farmers billions of dollars annually in pest management. Bat consumption of insects results in increased crop yields and reduced insecticide application, which in turn results in increased profits and improved environmental quality. Pest control services provided by bats in the United States range from $3.7 billion to $53 billion annually.[1] Agriculture plays a very important role in California's Central Coast Region; Monterey County agriculture generates $8.1 billion annually to the local economy.[2] As bat populations decline, the cost of their pest control will cascade into the agricultural industry.

A number of studies have been conducted on bat foraging and have found the following:

  • A nursing, female little brown bat eats more than her own body weight in insects (4-6 grams) nightly.[3]
  • Pallid bats consume large numbers of grasshoppers and crickets that can damage crops .[4]
  • A single red bat can eat 100 moths in a night, which would otherwise produce 25,000 new caterpillars that would eat crops.[5]
  • A colony of 150 bats will eat more than a million insects each season.[6]
  • Bat calls have been found to "chase" away pest insects such as cutworms, armyworms, and bollworms from crops up to 130 feet away.[6]

Bioindicator Species

Bats reflect the status of the plant populations where they roost and forage as well as the productivity of insect communities, making them ideal bioindicator taxa.[7] Bioindicators are used to show measurable responses to environmental stressors, such as water quality, that reflect wider-scale impacts on biota.

Pollution of surface water has been a long-standing problem for California's Central Coast Region, particularly in the Salinas River. Under Section 303d of the Clean Water Act, California has identified and listed impaired waterbodies in the Monterey Region; however, many water bodies still need to be evaluated. Utilizing bat surveys as a proxy for evaluating ecosystem health within the region could be a viable option.

Threats to Bat Species

Wind Energy

Wind energy has increased in popularity as a clean energy source; as of January 2020, there are six wind energy facilities in the Salinas Valley. [8] However, widespread deployment of wind turbines has resulted in the death of millions of bats. [9] Migratory bats, like the hoary bat and silver-haired bat, are disproportionately impacted by wind turbines.[10] Recent studies have evidence to suggest that bat fatalities at wind farms result from being physically struck by rotating blades in addition to lung collapse caused by the change in air pressure caused by turbines. [11] As a result of these unprecedented mortalities, coalitions such as Bats and Wind Energy Cooperative have brought representatives from government agencies, private industry, academic institutions, and non-governmental organizations together to curtail and prevent mortality of bats at wind energy facilities. Additionally, the California Energy Commission approved voluntary guidelines for reducing impacts to birds and bats from wind energy development.

Habitat Loss

As natural habitat becomes more scarce, bats struggle to find suitable roosting, foraging, and pupping habitat. Habitat loss may result from the destruction of habitat for human development, resource extraction, or agriculture. California's Central Coast region has experienced intense habitat destruction as land has been converted to agriculture. In Monterey County, 61% of the total land is designated as agricultural land.[2]

The destruction of habitat may also result in habitat fragmentation, which occurs when natural habitat patches are separated by areas of human disturbance. Unless connectivity is maintained between habitat patches, possibly through wildlife corridors, the utility of the remaining habitat may be reduced. Bats may require connectivity between roosting habitat and nightly foraging habitat, and isolated habitat patches may not be large enough to maintain a viable population. Without suitable habitat connectivity, migratory bat species may be at additional risk if forced to migrate through areas of human development.

Habitat loss may also occur when existing habitat is degraded by human activities. Gennet et al. (2013) documented the destruction or degradation of 13.3% of riparian and wetland vegetation along the Salinas River due to agricultural practices [12]. Degradation of habitat can also occur as a result of increased pesticide use[13], light pollution [14], or contaminated water.[15]

Image 1. White-nose syndrome Occurrence Map by Year

White-nose syndrome

White-nose syndrome (WNS) is a disease that has killed an estimated 6.7 million bats in North America since 2006.[16] WNS is caused by an invasive fungal pathogen (Pseudogymnoascus destructans), which was likely unintentionally introduced from Europe by humans.[16] This fungus kills hibernating bats but has been detected on migratory bats that remain unaffected by WNS.[16] During hibernation, bats lower their metabolic, heart, and respiratory rates which increases their energy efficiency and subsequently lowers their immune systems.[17] This fungus feeds on the soft tissue of hibernating bats (i.e. face and wings) and causes them to arouse from torpor, thus depleting their limited fat reserves and resulting in death.[16] The mortality rate of a bat with WNS is estimated to be as high as 90-100%.[18] Unfortunately, a population-wide treatment for WNS has not been found.

WNS syndrome has been detected in 33 states, including California, which recorded its first confirmed case in Plumas County during 2019 surveillance efforts.[19] Although WNS has not been detected in California's Central Coast Region, the recent detection in northern California has prompted CDFW to increase statewide surveillance efforts in addition to monitoring impacts on bat populations and assisting with research on disease management.[19]

Lack of Research

There is limited knowledge on the life histories of bat species within California's Central Coast Region and few studies have been completed within the region. Relative threats and benefits are thus based on studies in similar regions and differences may be observed in California's Central Coast Region with adequate studies. This gap in knowledge can possibly be attributed to the accelerated privatization within California's Central Coast Region coupled with the inherent difficulties presented with studying a small, nocturnal mammal.

Bat Species of California's Central Coast Region

The following bat species are found within California's Central Coast region. Information is presented on the roosting habitat and presumed wintering behavior of each species, although this is poorly known for some species in the region. The conservation status of each species is also included. Though certain species within the region have received Special Status designation, none have received formal legal protection under the Federal or California Endangered Species Act, predominantly due to the lack of research.

Key to Conservation Status Abbreviations

Agencies & Organization Designation
California Department of Fish and Wildlife Species of Special Concern SSC
United States Forest Service (USFS) Sensitive Species[20] USFS
United States Bureau of Land Management (BLM) Sensitive Species[21] BLMS
Western Bat Working Group High Priority WBWG(H)
Western Bat Working Group Medium Priority WBWG(M)
Western Bat Working Group Low Priority WBWG(L)
Family Scientific Name Common Name Roosting Habitat Wintering Behavior Conservation Status
Molossidae Eumops perotis Western mastiff bat rock crevices on cliff faces Resident (periodically active) WBWG(M); SSC; BLMS
Molossidae Tadarida brasiliensis Mexican free-tailed bat; Brazilian free-tailed bat caves, rock crevices on cliff faces, urban structures (buildings, culverts, under bridges) Migratory (primarily) WBWG(L)
Vespertilionidae Antrozous pallidus Pallid bat caves/mines, rocky outcrops, cliffs, trees, urban structures (buildings, porches, bridges) Unknown (hypothesized to be resident/short-distance migrant) WBWG(L); SSC; BLMS
Vespertilionidae Corynorhinus townsendii (formerly Plecotus townsendii) Townsend's big-eared bat caves and mines Resident (Hibernator) WBWG(H); SSC; BLMS
Vespertilionidae Eptesicus fuscus Big brown bat caves, mines, rock crevices, trees, urban structures (buildings, bridges) Resident (Hibernator) WBWG(L)
Vespertilionidae Euderma maculatum Spotted bat caves, cracks/crevices on cliff faces Unknown (hypothesized to be residents and periodically active at lower elevations) WBWG(M); SSC; BLMS
Vespertilionidae Lasionycteris noctivagans Silver-haired bat hollow trees, under sloughing bark, in rock crevices; occasionally under wood piles/leaf litter and in urban structures (buildings, mines) Migratory WBWG(M)
Vespertilionidae Lasiurus blossevillii Western red bat trees, shrubs; occasionally caves Unknown (hypothesized to be a migratory) WBWG(H)
Vespertilionidae Lasiurus cinereus Hoary bat trees; occasionally caves, rock ledges, and in urban structures (buildings) Migratory WBWG(M)
Vespertilionidae Myotis californicus California myotis caves, mines, rocky hillsides, under tree bark, urban structures (buildings) Hibernator WBWG(L)
Vespertilionidae Myotis ciliolabrum Western small-footed myotis cliff and rock crevices, caves, urban structures (buildings, bridges, mines) Unknown (hypothesized to be a hibernator) WBWG(M); SSC; BLMS; USFS
Vespertilionidae Myotis evotis Long-eared myotis tree bark, hollow trees, caves, mines, and rocky outcrops close to the ground Unknown (hypothesized to be a hibernator) WBWG(M); SSC; BLMS
Vespertilionidae Myotis lucifugus Little brown myotis generalist (will roost in natural and urban structures) Unknown (hypothesized to be a hibernator) WBWG(M)
Vespertilionidae Myotis thysanodes Fringed myotis cliff faces, rocks, trees, urban structures (buildings, bridges, mines) Unknown (hypothesized to be a hibernator) WBWG(M); SSC; BLMS; USFS
Vespertilionidae Myotis volans Long-legged myotis cracks in the ground, cliff faces, under tree bark and in tree hollows, urban structures (abandoned buildings) Hibernator WBWG(M); SSC; BLMS
Vespertilionidae Myotis yumanensis Yuma myotis cliff crevices, caves, trees, urban structures (mines, bridges, buildings) Unknown (hypothesized to be a hibernator) WBWG(L); BLMS
Vespertilionidae Parastrellus hesperus Western pipistrelle; Canyon bat rocky canyons and outcrops, caves, urban structures (mines) Hibernator WBWG(L)

Reporting Sick, Dead or Injured Bats

California Department of Fish and Wildlife (CDFW) encourages people to report any unusual behavior observed in bats, such as trouble flying, flying during the daytime or during cold winter weather, dying or sick bats (on the ground, unable to fly), or bats that have a white fungus on their face or wings to by submitting information here.

If you have found a bat that appears to be injured, contact your local bat rehabilitator:



  1. Boyles JG, Cryan PM, McCracken GF, Kunz TH. 2011. Economic Importance of Bats in Agriculture. Science. 332(6025)41:42. https://science.sciencemag.org/content/332/6025/41
  2. 2.0 2.1 Agricultural Economic Contributions.Farm Bureau of Monterey Count. Accessed April 2020. http://montereycfb.com/index.php?page=economic-contributions
  3. Long RF, Kiser WM, Kiser SB. 2006. Well-Placed Bat Houses Can Attract Bats to Central Valley Farms. California Agriculture. 60(2)91:94. https://escholarship.org/uc/item/9bs900wj
  4. Summary of Agricultural Wildlife Conservation Center Project. Bat Conservation International. Accessed April 2020. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_010028.pdf
  5. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_010028.pdf
  6. 6.0 6.1 Long, RF, Simpson T, Ding T, Heydon S, Reil W. 1998. Bats Feed on Crop Pests in Sacramento Valley. California Agriculture. 52(1)8:10. http://calag.ucanr.edu/download_pdf.cfm?article=ca.v052n01p8
  7. Jones G, Jacobs DS, Kunz TH, Willig MR, Racey PA. 2009. Carpe Noctem: the Importance of Bats as Bioindicators. Endangered Species Research. (8):93-115. https://www.int-res.com/articles/esr2009/8/n008p093.pdf
  8. U.S. Wind Turbine Database. United States Geological Survey (USGS). Archived January 2020. https://eerscmap.usgs.gov/uswtdb/viewer/#7.28/36.465/-120.467
  9. Bat fatalities at Wind Turbines—Investigating the Causes and Consequences. United States Geological Survey(USGS). Accessed April 2020.https://www.usgs.gov/centers/fort/science/bat-fatalities-wind-turbines-investigating-causes-and-consequences?qt-science_center_objects=0#qt-science_center_objects
  10. Bat and Wind Energy Cooperative Report. Evaluating the Effectiveness of ultrasonic acoustic deterrent for reducing bat fatalities at wind turbines. Archived December 2011. https://tethys.pnnl.gov/sites/default/files/publications/Arnett-Final-Report-2009.pdf
  11. Horn JW, Arnett EB, Kunz TH. 2008. Behavioral Response of Bats to Operating Wind Turbines. The Journal of Wildlife Management.72(1)123-132. http://batsandwind.org/wp-content/uploads/hornetal2008.pdf
  12. Gennet S, Howard J, Langholz J, Andrews K, Reynolds MD, Morrison SA. 2013. Farm practices for food safety: an emerging threat to floodplain and riparian systems. Frontiers in Ecology and the Environment 11(5): 236-242. http://onlinelibrary.wiley.com/doi/10.1890/120243/full
  13. Frank E. 2016. Declining Bat Populations, Increased Pesticide Use & Infant Mortality. https://pdfs.semanticscholar.org/41a2/e60c16503c1425b0ab001b68485ab2b90b1f.pdf
  14. How Light from Street Lamps and Trees Influence the Activity of Urban Bats: A Complex Relationship. Science Daily. Archived March 2019. Accessed April 2020. https://www.sciencedaily.com/releases/2019/03/190327080702.htm
  15. Laverty, T. 2018. Where Clean Drinking Water is Hard to Find, Bats Could Lead the Way. Smithsonian Magazine. Accessed April 2020. https://www.smithsonianmag.com/science-nature/where-clean-drinking-water-is-hard-to-find-bats-could-lead-way-180968941/
  16. 16.0 16.1 16.2 16.3 White-nose Syndrome: Questions and Answers. Center for Biological Diversity. Accessed April 2020. https://www.biologicaldiversity.org/campaigns/bat_crisis_white-nose_syndrome/Q_and_A.html
  17. Bats: Hibernate or Migrate. National Park Service (NPS). Archived October 2016. Accessed April 2020. https://www.nps.gov/subjects/bats/hibernate-or-migrate.htm
  18. White Nose Syndrome. Wildlife Health Lab at Cornell University. Archived 2018. Accessed April 2020. https://cwhl.vet.cornell.edu/disease/white-nose-syndrome
  19. 19.0 19.1 Deadly Bat Fungus Detected in California. White-Nose Syndrome Response Team. California Department of Fish and Wildlife (CDFW) and U.S. Fish & Wildlife Service (USFWS) Press Release. Archived July 2019. Accessed April 2020. https://www.whitenosesyndrome.org/press-release/deadly-bat-fungus-detected-in-california
  20. California Department of Fish and Wildlife (CDFW), Natural Diversity Database Special Status Animals List. Archived August 2019. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=109406&inline
  21. Bureau of Land Management (BLM) Special Status Animals List. Archived December 2009. https://www.blm.gov/sites/blm.gov/files/documents/files/Programs_FishandWildlife_BLMCA%20Special%20Status%20Species.pdf


This page may contain student work completed as part of assigned coursework. It may not be accurate and does not necessarily reflect the opinion or policy of CSUMB, its staff, or students.