Overview

Brief Summary

The Virginia big-eared bat (Plecotus townsendii virginianus) is a medium-sized (3-4 in or 8.5-10cm long) colonial vesper bat (family Versperidae) with ears more than 1 inch (2.5cm) long.  In 2005 P. t. virginianus officially became the state bat of Virginia.  These bats are non-migratory and roost exclusively in limestone caves summer and winter.  Surveys in 2009 revealed that Virgina big-eared bats roost in just 15 caves in the Appalachian mountains of eastern Kentucky, eastern West Virginia, southwest Virginia and northwestern North Carolina, and estimated a total hibernating population of about 12,000 for the subspecies (Stihler 2011).  Over the winter, the bats congregate in hibernation sites (hibernacula) in dense mixed-sex clusters near the entrance or in well-ventilated parts of caves where temperatures stay above 32 degrees F (0 degrees C).  The bats mate in the fall and winter, sometimes while females are still in a torpid state.  Females store the sperm, ovulate in the spring, and then disperse in summer to maternity colonies where they give birth to a single offspring.  Mothers provide care and nurse their young until they mature at 6-8 weeks of age.  Virginia big-eared bats are insectivores and feed only at night; a majority of their diet is moths (US Fish and Wildlife Service 2013; Virginia Department of Game and Inland Fisheries 2013; Lacki and Dodd 2011; Loeb, Lacki and Miller 2011).

Virginia big-eared bats and their close relatives the Ozark big-eared bats (P. t. ingens) are remnant populations disjunct from each other and from the other two more populous subspecies of Townsend’s big eared bats (P. t. pallescens and P. t. townsendii), which have large ranges across the western half of the United States.  The eastern subspecies are thought to have diverged from the western populations during the ice age and research groups are investigating whether these subspecies should be considered separate species.  There is also evidence for recognizing and managing the colonies within the Virginia big-eared bat subspecies as evolutionarily distinct units, since the colonies are isolated and probably do not interbreed (Lack and Van Den Bussche 2009; Piaggio and Perkins 2005; Bayless et al. 2011).  Both eastern subspecies are federally listed as endangered and listed as imperiled by NatureServe due to their small, restricted populations and vulnerability to human disturbances. 

Spelunking (caving), vandalism and intruding humans are currently the major threats to the Virginia big-eared bat, as a whole colony can easily abandon their cave and offspring when disturbed.  Furthermore, when aroused in winter the unplanned increase in body temperature uses up the limited energy reserves required to last their full hibernation period.  Other threats to these bats are decline of insect food sources as a result of pesticide use and human development and mining activities reducing already limited number of appropriate roosting/breeding caves and foraging areas (Virginia Department of Game and Inland Fisheries 2013; Bayless et al. 2011).  Virginia big-eared bats roost in caves known to contain other species of bats afflicted with white nose syndrome (WNS), a fungus-related illness that has been decimating North American bat species since 2006.  Although infection could have particularly damaging ramifications to Virginia big-eared bats, they do not seem to be affected by this disease yet (Douglas 2008; Platt 2012; Youngbaer 2013; Gomez 2010).  The National Zoo attempted to protect Virginia big-eared bats from WNS in 2010, a controversial project (Smithsonian Newsdesk 2010).

The Virginia big-eared bat is confusable with closely related Rafinesque’s bat (Corynorhinus rafinesquii), which has an overlapping range.  Townsend’s big-eared bat subspecies have a history of taxonomic name changes and are known by generic names Corynorhinus, Synotus, and Plecotus.  Recent molecular work differentiates the new world species as Corynorhinus and old world species as Plecotus (Gruver and Keinath 2003).

  • Bayless, ML, MK Clark, RC Stark, BS Douglas, and SM Ginger, 2011. Distribution and status of eastern big-eared bats (Corynorhinus spp.) In Loeb, S.C., Lacki, M.J., Miller, D.A., eds. Conservation and management of eastern big-eared bats: a symposium. Gen. Tech. Rep. SRS-145. Ashevill, NC: US Department of Agriculture, Forest Service, Southern Research Station. Retrieved September 11, 2013 from http://rafbat.org/gtr_srs145.pdf.
  • Douglas, B. 2008. Virginia big-eared bat (Corynorhinus townsendii virginianus) 5 year review: Summary and evaluation. US Fish and Wildlife Service. Retrieved September 11, 2013 from http://www.fws.gov/northeast/EcologicalServices/pdf/endangered/Virginia%20big%20ear%20bat%205year.pdf.
  • Gruver, JC. and DA Keinath, 2003. Species assessment for Townsend’s big-eared bat (Corynorhinus [=Plecotus] townsendii) in Wyoming. Prepared for US Department of the Interior, Bureau of Land Management. Wyoming State office, Cheyenne, Wyoming. Retrieved September 11, 2013 from http://www.blm.gov/pgdata/etc/medialib/blm/wy/wildlife/animal-assessmnts.Par.35707.File.dat/TownsendBig-earedBat.pdf.
  • Lack, J.B. and R.A. Van Den Bussche, 2009. A Relaxed Molecular Clock Places an Evolutionary Timescale on the Origins of North American Big-Eared Bats (Vespertilionidae: Corynorhinus) Acta Chiropterologica 11(1):15-23. doi: http://dx.doi.org/10.3161/150811009X465668
  • Lacki, MJ, and LE Dodd, 2011. Diet and foraging behavior of Corynorinus in Eastern North America. In Loeb, S.C., Lacki, M.J., Miller, D.A., eds. Conservation and management of eastern big-eared bats: a symposium. Gen. Tech. Rep. SRS-145. Asheville, NC: US Department of Agriculture, Forest Service, Southern Research Station. Retrieved September 11, 2013 from http://rafbat.org/gtr_srs145.pdf.
  • Loeb, SC, MJ Lacki, DA Miller, 2011. Conservation and management of eastern big-eared bats: an introduction. In Loeb, S.C., Lacki, M.J., Miller, D.A., eds. Conservation and management of eastern big-eared bats: a symposium. Gen. Tech. Rep. SRS-145. Asheville, NC: US Department of Agriculture, Forest Service, Southern Research Station. Retrieved September 11, 2013 from http://rafbat.org/gtr_srs145.pdf.
  • Stihler, C.W., 2011. Status of the Virginia big-eared bat (Corynorhinus townsendii virginianus) in west Virginia: Twenty-seven years of monitoring cave roosts. In Loeb, S.C., Lacki, M.J., Miller, D.A., eds. Conservation and management of eastern big-eared bats: a symposium. Gen. Tech. Rep. SRS-145. Asheville, NC: US Department of Agriculture, Forest Service, Southern Research Station. Retrieved September 11, 2013 from http://rafbat.org/gtr_srs145.pdf.
  • Piaggio, A. J., and S. L. Perkins. 2005. Molecular phylogeny of North American long-eared bats (Vespertilionidae: Corynorhinus); inter- and intraspecific relationships inferred from mitochondrial and nuclear DNA sequences. Molecular Phylogenetics and Evolution, 37: 762–775.
  • Platt, JR. 2012. Bat-killing fungus continues deadly spread; death toll now at 2 million. Scientific American Blogs. Retrieved September 11, 2013 from http://blogs.scientificamerican.com/extinction-countdown/2012/04/03/bat-killing-fungus-continues-deadly-spread/
  • Smithsonian Newsdesk, March 5, 2010. Smithsonian’s National Zoo working to understand and save endangered bats. Newsroom of the Smithsonian. Retrieved September 11, 2013 from http://newsdesk.si.edu/releases/smithsonian-s-national-zoo-working-understand-and-save-endangered-bats
  • US Fish and Wildlife Service, 2013. Species profile: Virginia Big-Eared bat (Corynorhinus (=plecotus) townsendii virginianus). Retrieved September 11, 2013 from http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=A080.
  • Virginia Department of Game and Inland Fisheries, 2013. Virginia Big-Eared Bat. Retrieved September 11, 2013 from http://www.dgif.virginia.gov/wildlife/virginia_big_eared_bat.asp.
  • Youngbaer, P. 2013. Summer update. National Speleological Society, White nose syndrome page. Retrieved September 11, 2013 from http://www.caves.org/WNS/
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Distribution

endemic to a single nation

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National Distribution

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

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Global Range: (250-20,000 square km (about 100-8000 square miles)) Appalachian Mountains in Virginia, West Virginia, North Carolina, and eastern Kentucky. Presently occurs in decreased numbers throughout much of the historic range. Largest colonies are in several caves in Pendleton County, West Virginia; some caves serve as both hibernation and maternity sites, others are primarily maternity caves Colonies occur also in Lee County and surrounding counties, Kentucky (the best known site being Stillhouse Cave); in Bath, Highland, Rockingham, Bland, and Tazewell counties, Virginia (Dalton 1987); and in Avery and Watauga counties, North Carolina (including Black Rock Cliffs Cave) See Matthews and Moseley (1990) and Handley (1991).

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Historic Range:
U.S.A. (KY, NC, WV, VA)

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Physical Description

Diagnostic Description

Differs from subspecies INGENS in being more sooty dorsally and averaging slightly smaller in all dimensions; also, the first upper incisor rarely has a trace of a secondary cusp, and the rostrum is less heavy and inflated (Handley 1959).

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Type Information

Type for Corynorhinus townsendii virginianus Handley, 1955
Catalog Number: USNM 269163
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Sex/Stage: Male; Adult
Preparation: Skin; Skull
Collector(s): W. Stephenson
Year Collected: 1939
Locality: Schoolhouse Cave, 22 mi SW Petersburg, 4.4 mi NE Riverton, Pendleton County, West Virginia, United States, North America
Elevation (m): 672
  • Type: Handley, C. O. 1955 May 27. Journal of the Washington Academy of Sciences. 45: 148.
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Ecology

Habitat

Comments: Caves typically in limestone karst regions dominated by mature hardwood forests of hickory, beech, maple, and hemlock (Matthews and Moseley 1990). Prefers cool, well-ventilated caves for hibernation (Matthews and Moseley 1990); roost sites are often near cave entrances or in places where there is considerable air movement (Handley 1991). Males and females hibernate together. In summer, males occur singly or in groups in caves (Handley 1991). In eastern Kentucky, feeding roosts were in cliffs adjecent to two maternity roosts and one bachelor roost (Burford and Lacki 1998). Individuals may move from one roost to another at any season.

Maternity colonies settle deep within caves, far from entrance (Matthews and Moseley 1990); these caves are warmer than those used for hibernation. In Kentucky, used limestone caves, except in one instance in which a sandstone rock shelter was used (Lacki et al. 1994).

In Kentucky, often detected in old fields and above cliffs (Burford and Lacki 1995).

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Migration

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Fairly sedentary; not known to migrate more than about 64 km between hibernation and maternity caves (Matthews and Moseley 1990).

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Trophic Strategy

Comments: Feeds principally on moths. Forages over fields and woods, with individuals routinely traveling 3-5 miles from roost cave to foraging area (End. Sp. Tech. Bull., Sept./Dec. 1991). In eastern West Virginia, Lepidoptera was the most important insect order in the diet, followed by Coleoptera, Diptera, and Hymenoptera; compared to availability, selectively consumed Lepidotera and avoided Coleoptera; forest insect comprised a substantial part of the diet (Sample and Whitmore 1993).

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Population Biology

Number of Occurrences

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 6 - 20

Comments: Known from about 15 caves in 4 states (Kentucky-1, Virginia-2, West Virginia-11, North Carolina-1). Other colonies have either declined or disappeared.

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Global Abundance

10,000 to >1,000,000 individuals

Comments: Total known population was 3,866 bats (ll colonies) in 1984 (Bagley and Jacobs 1985), about 10,000 in the late 1980s (Dalton 1987). In 1987, the total West Virginia population was 8000, based on a count of about 3500 females, up almost one-third since 1983 (Matthews and Moseley 1990). A 1991 count of the 9 summer colonies in West Virginia yielded 4455 individuals, a 15 percent increase from the 1990 count and a 20 percent increase from 1984 (End. Sp. Tech. Bull., Sept./Dec. 1991); the count was basically unchanged in early 1992, but in May 1992 the largest known maternity colony (1300 individuals) of this subspecies was discovered (1992 End. Sp. Tech. Bull. 17(12):18). The largest known concentration of this species is in Hellhole Cave, West Virginia; the count for the 1994-1995 season was 6378 individuals (End. Sp. Bull. 20(4):21). As of the mid-1990s, West Virginia/North Carolina population was more than 13,000 (1994 End. Sp. Tech. Bull. 19(5):14). In Kentucky, the hibernating population in Stillhouse Cave increased from 1700 in 1982 to 2600 in 1987 (Matthews and Moseley 1990). Virginia population in the 1980s was about 2000 and stable (Dalton 1987, Handley 1991). Total population in 1997 probably was less than 20,000 (Pupek 1997).

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General Ecology

Hibernates singly, or in small clusters; sometimes in large tight clusters of hundreds (Caire et al. 1989, Schmidly 1991, Handley 1991).

Pre-weaning post-natal mortality generally is low. Adult survivorship is relatively high.

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Life History and Behavior

Cyclicity

Comments: Activity usually begins well into the night, late relative to other bats. After an initial feeding period, roosts and rests during the night, presumably before a later feeding bout. Commonly arouses in winter, changing position within a hibernaculum or moving to a nearby cave or mine.

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Reproduction

Mating begins in late summer/early autumn, continues into winter. Ovulation and fertilization are delayed until late winter/early spring. Maternity colonies form as early as late winter (March) or as late as late spring (June), apparently depending on when the roost site reaches a suitably warm temperature. Gestation lasts 2-3.5 months. Litter of one is born in late spring/early summer. Young can fly at about 2.5-3 weeks, weaned by 6-8 weeks, leave cave to forage by the end of July or early August. Most individuals leave the nursery cave by mid- to late September. Females are sexually mature their first summer. Males may not be sexually active until their second year. Nearly all adult females breed every year. Females form nursery colonies; males roost separately ( solitary or in large bachelor groups) during this time.

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Conservation

Conservation Status

National NatureServe Conservation Status

United States

Rounded National Status Rank: N2 - Imperiled

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NatureServe Conservation Status

Rounded Global Status Rank: T2 - Imperiled

Reasons: Small range in several states in the Appalachian Mountains region; total population exceeds 10,000, has increased in recent years; occurs only in about 15 caves, of which about 5 contain the bulk of the population; vulnerable to disturbance by humans.

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Current Listing Status Summary

Status: Endangered
Date Listed: 12/31/1979
Lead Region:   Northeast Region (Region 5) 
Where Listed: Entire


Population detail:

Population location: Entire
Listing status: E

For most current information and documents related to the conservation status and management of Plecotus townsendii virginianus, see its USFWS Species Profile

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Global Short Term Trend: Relatively stable (=10% change)

Comments: Through the late 1980s, the population of reproducing females increased by nearly 30% since surveys were initiated in 1983 (Matthews and Moseley 1990). USFWS (1990) categorized the status as "improving," with the population "stable overall." West Virginia/North Carolina population increased by an order of magnitude between 1979 and 1994 (1994 End. Sp. Tech. Bull. 19(5):14). Populations in some West Virginia caves grew as much as 350 percent from 1983 to 1995 (Pupek 1997).

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Threats

Degree of Threat: A : Very threatened throughout its range communities directly exploited or their composition and structure irreversibly threatened by man-made forces, including exotic species

Comments: The growing popularity of spelunking is a tremendous threat to these bats. Very intolerant of disturbance in summer and winter. Former decline probably is attributable to human intrusion into caves, which depletes energy reserves of aroused bats and may lead to cave abandonment if disturbance is frequent. Forest defoliation by gypsy moth could adversely affect native Lepidoptera and impact bat population (Sample and Whitmore 1993). In some areas, feral cats prey on the bats.

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Management

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: At least five of the caves have been fenced to limit human visitation. Do not know how many are on private land. As of late 1991, all colonies in West Virginia were protected by gates, fences, or landowner agreements.

Needs: All existing maternity and hibernation caves should be targeted for some protection, especially the four with large populations.

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Wikipedia

Virginia big-eared bat

The Virginia big-eared bat (Corynorhinus townsendii virginianus)[2] is one of two endangered subspecies of the Townsend’s Big-Eared bat. It is found in West Virginia, North Carolina, and Kentucky. In 1979, the US Fish and Wildlife Service categorized this as an endangered species. There are about 20,000 left and most of them can be found in West Virginia.[3] The Virginia Big-Eared Bat is the state bat of Virginia.[4] The bat is part of life in West Virginia. They eat lots of bugs around the community and keep out biting insects.

Description[edit]

Virginia big-eared bat (C.t. virginianus).JPG

The Virginia Big-Eared Bat has light to dark brown fur depending on age. Their fur is long and soft and the same from its base to its tip.[5] This species is one of the largest cave-dwelling bats in its range, and weights between 7 and 12 grams. The bat is recognized by its big ears, which are over 2.5 centimeters long. Their ears reach back to half the length of their body when at rest.[5] It also has a globular shaped muzzle and elongated nostrils.[5] Its whole body is 98 millimeters long. The forearms of the bat are anything from 39 to 48 millimeters, the tail can be about 46 millimeters, and the hind foot can be about 11 millimeters.

Mating happens in the fall and the winter. Females ovulate in the winter and the spring and can store the sperm from the male until then. The bats are pregnant for 3 months and have their one pup in May or June. In 2 months the pups fully develop and are able to fly from their roost.[6]

These bats live in caves throughout the whole year and prefer caves surrounded by oak-hickory forest. They are usually located in mountainous limestone regions.[5] During the maternity period the female bats stay in the caves. Most male bats don’t stay with the female bats during this period. They aren’t migratory and usually stay close to their caves. In the winter this species hibernates rather than migrates.[5] Usually these bats only leave to hunt for food.They are nocturnal hunters and feeders.[5] In Virginia they are known to hunt in fields and in Kentucky they are known to hunt by cliffs. Research shows that hunting patterns are very varied. They use their sonar to see insects while flying on the edges of the forests where they hunt. They benefit us because they hunt harmful insects.[2] They hunt for insects such as: small moths, beetles, flies, lacewings, bees and wasps.[3]

Threats to this species include disturbance from noise, bright lights, and human presence.[5]

Diet[edit]

The Virginia big-eared bat consumes insects, with small moths making up the significant portion of the diet.[7]

Virginia Big-Eared Bats are insectivores. Insectivores are carnivores that predominantly eat insects as their main resource of sustenance. The Virginia Big-Eared Bat has become adapted to twilight, evening and dawn feeding times. They rely on these nocturnal times to fly around and capture their prey. They fly and hunt for their prey all around the forestry, caves and woodland. They use this time to hunt tiny flying insects that are airborne and soaring through the nighttime air. Bats have an uncanny and complex sense of hearing. This high-level intelligence of hearing allows The Virginia Big-Eared Bats to quickly and immediately identify and apprehend its flying prey.[8]

The bat's pristine sense of hearing is referred to as echolocation. Echolocation is a natural ability that bats have. This ability allows the bat to make sounds that then echo off of upcoming prey, such as flying, mosquitoes, moths, beetles, termites and flies. Any of these insects within reach will be heard and then eaten by the Virginia Big-Eared Bat. Echolocation is necessary and indispensable to the bats survival. Without this system the bat would not be able to localize and specify flying insects and food.[9]

Studies show that, when analyzed, 97% of the fecal pellets and contents of the stomachs of The Virginia Big-Eared Bats showed that the bat had consumed and digested Lepidoptera.[10] Lepidoptera is a distinct classification of insects primarily known as butterflies and moths.[11]

The Virginia Big-Eared Bat of Kentucky had a similar study done, examining the absorbed and processed fecal pellets and stomach contents of the bats in and around the caves. Recognized and acknowledged food found and processed showed that in this particular area The Virginia Big-Eared Bat had a diet of Lepidoptera (moths) and Coleoptera (beetles), in addition to spiders, crickets, roaches, flies, ants, wasps and bees.[12]

Range and habitat[edit]

According to "Virginia Big-Eared Bats (Corynorhinus Townsendii Virginianus)", Virginia Big-Eared Bats can be found in isolated populations located in eastern Kentucky, eastern West Virginia, southwestern Virginia, and northwestern North Carolina. They are nonmigratory bats, and live in caves all year round. This subspecies of Townsend's Big-Eared Bats prefer caves made from limestone bedrock. The regions they are found in are usually filled with oak-hickory or beech-maple-hemlock forest.[13]

Since Towsend’s Big-Eared Bats are usually found in areas to the West of the Rocky Mountains, it seems that there is a big distance between each subspecies of these bats. According to many scientists, it seems that this separation has been present since the last ice age.[14] It is hard for these bats to find suitable habitats due to their strict requirements when it comes to the temperature and humidity levels of caves.[14]

Habitat and behavior[edit]

High activities of these bats have also been found high above cliffs in the Daniel Boone National Forest. Many studies have seemed to have inconsistent results, showing high bat activity on cliffs, forest habitats, and open fields/pastures.[15] Bats were seldom seen flying over open spaces or flying above human occupied lands. The farthest a Virginia Big-Eared Bat has been observed foraging was 8.4 km from its roost. This was shown through radio telemetry.[16] This study, located in Lee County, Kentucky, studied hills consisting of sandstone cliffs. The elevations varied from 182 meters to 424 meters, and limestone deposits under the sandstone resulted in the formation of caves. These caves are an ideal habitat for the Virginia Big-Eared Bats. There is a large amount of variability when it comes to the use of foraging habitats between geographically isolated populations. In Kentucky, old fields have been shown to be important components of the foraging habitat of this subspecies. As a result, old fields should be taken care of and isolated from humans in the Daniel Boone National Forest. By doing this, this subspecies may use the location as a foraging habitat.[15]

Habitat and seasons[edit]

A tightly packed cluster of hibernating Virginia big-eared bats

During hibernation, these bats need an environment that ranges from 32 to 54 degrees Fahrenheit.[13] Virginia Big-Eared Bats store a certain amount of body fat in the winter during their hibernation, so when they are disturbed and the temperature of the cave changes, they must use up their body fat to raise the temperature of their bodies in order for them to leave the disturbed area. The burning of their fat makes them very weak and causes female bats to leave their babies if a maternity site is disturbed or altered. [14] This is one of the main reasons why this subspecies of bats hibernate in tight clusters. These clusters occur at the opening of each cave, due to the suitable temperature and good ventilation. Maternity colonies are found in the warmer parts of the caves.[13]

Hibernating Virginia big-eared bats

Most of these bats reside in Limestone caves based on the thermal warming of the roost, which is the most important factor when it comes to the habitat the mother’s need when pregnant. Maternity patterns and timing are important because they change the requirements that the mothers need when it comes to habitat. Roosts in Virginia showed a decrease in the amount of bats in late May to early June.In July, the population and activity levels at night increased drastically in July, showing that July is the most popular breeding and maternity time.There was a large increase in the movement and switching of roosts in August when it came to the males. However, it is unknown where the males spend the rest of their summer.[17]

Over 5,000 Virginia big-eared bats, approximately 40 percent of the species' total population were found hibernating in Stillhouse Cave, in the Daniel Boone National Forest of Kentucky.[18]

Evolution[edit]

The Virginia Big-Eared Bat is classified as Corynorhinus townsendii virginianus. The Corynorhinus genus, called the North American Big-Eared Bats, consists of three different species located from central Mexico to southwestern Canada (C. mexicanus, C. rafinesquii, C. townsendii). The subspecies of C. townsendii are C. t. townsendii, C. t. pallescens, C. t. australis, C. t. ingens, and C. t. virginianus, all of which primarily occupy North America. It is hypothesized that the MRCA, most recent common ancestor, of the Corynorhinus species diverged into two different lineages, creating a C. rafineesquii ancestor and C. mexicanus/ C. townsendii ancestor, during the warm periods of the Pliocene, approximately 5.0-2.5 mya. Then, during the cooling period of the early Pleistocene, cerca 2.5 mya, the C. mexicanus/ C. townsendii lineage split, separating C. mexicanus and C. townsendii. During this same period, the C. townsendii species was further divided into three lineages, isolating a C. t. townsendii ancestor, a C. t. pallescens/ C. t. australis ancestor, and a C. t. ingens/ C. t. virginianus ancestor. Subsequent glacial advances around 1.8-1.0 mya finally divided all these lineages into the subspecies that are found today. The events that caused the subspeciation between C. t. ingens and C. t. virginianus are believed to have separated the already disjunct populations from each other, leading the then unified species towards separate refugia, leading to divergence and subsequent subspeciation.[19]

Conservation status[edit]

Citizens of West Virginia were the first to notice a decline in the amount of Virginia Big-Eared Bats in local caves. The population of Virginia Big-Eared Bats was estimated to be between 2,500 and 3,000 individuals in 1976.[20] The cause of the decline is thought to be human sport, including spelunking, and general human disturbance in caves inhabited by the bats, which have lower tolerance to outside activity. The bats could also have been collected as a token for cave researchers because of their unique appearance.[21] Inhabiting mines have been shown to also result in a decrease in population.[22] Deforestation also presents itself as a problem. The Virginia Big-Eared Bat eats a variety of moths, some 45 different species, but 77.8% of those moths grow from larva that are dependent upon woody, forest plants for survival. Destruction of this environment would hurt the bats through both the destruction of habitable areas as well as by lowering of the population of their prey.[23]

The Virginia Big-Eared Bat was listed as endangered in December 31, 1979, and five caves in West Virginia were declared critical habitat for the bat.[20] These caves were closed off to the public. The recovery plan was proposed in 1984.[21] Cave sites preferred by Virginia Big-Eared Bats would be gated off to prevent human disturbance, and colonies would be monitored for population surveys. Specifically, the recovery plan under the Endangered Species Act required the monitoring of population trends with minimally invasive infrared sensors, searching for undocumented caves of importance to Big-Eared Bats, preventing human disturbance of said caves by installing gates and signs, appropriate agencies protecting the caves providing habitat for solitary big-eared bats, preventing changes and damage to essential habitat, developing and maintaining support for species protection, preparing and maintaining a management profile for each colony site to record population and activity, and appointing a coordinator for all recovery and research efforts.[21]

A 77% increase in population was recorded in 2009 since an initial report in 1983.[20] The population increase of the Virginia Big-Eared Bat is considered to be a successful revival due to the Endangered Species Act.[24]

Torpid Virginia big-eared bats (Corynorhinus townsendii virginianus) with condensation photographed during a hibernaculum survey

Threat of White nose syndrome[edit]

White-nose syndrome is the worst wildlife disease in recent history that is currently decimating North American cave-hibernating bat populations.[25] This epidemic is responsible for mass mortalities in hibernating North American bats, and is caused by a uniquely cold-adapted fungus Pseudogymnoascus destructans. The fungus begins to grow on bats during the winter hibernation season, when bats are in torpor and immune-compromised. The body temperature of a hibernating bat is the optimal fungal growth environment.[25] The fungus has affected 90% of species that hibernate in caves for the winter. Pseudogymnoascus destructans spores have been found growing on the Virginia big-eared bat. To date, no WNS mortality in this species has been observed although the syndrome has killed millions of its fellow cave-dwelling species.[26]

See also[edit]

References[edit]

  1. ^ Arroyo-Cabrales, J. & Ticul Alvarez Castaneda, S. (2008). "Corynorhinus townsendii". IUCN Red List of Threatened Species. Version 2009.2. International Union for Conservation of Nature. Retrieved 2010-01-25. 
  2. ^ a b US Fish and Wildlife Service (2003), Virginia big-eared bat 
  3. ^ a b Strickland, Johnson (2003), Biological Assessment for the Federally Endangered Indiana Bat (Myotis sodalis) and Virginia Big-eared Bat (Corynorhinus townsendii virginianus), pp. 9–10 
  4. ^ Virginia State Bat
  5. ^ a b c d e f g Virginia Big-Eared bat 
  6. ^ US Fish and Wildlife Service (2013), Virginia Big-Eared bat (Corynorhinus (=plecotus) townsendii virginianus) 
  7. ^ Stihler, Craig (2006), WILDLIFE DIVERSITY NOTEBOOK: Virginia big-eared bat 
  8. ^ Moore, Kimberly (2013), Virginia Big-Eared Bat: An Endangered Species of the Commonwealth 
  9. ^ Harris, Tom, How Bats Work 
  10. ^ Sample, Whitmore (1993), FOOD-HABITS OF THE ENDANGERED VIRGINIA BIG-EARED BAT IN WEST-VIRGINIA, pp. 428–435 
  11. ^ Harris, Mary S (2002), Lepidoptera 
  12. ^ Bauer, Elliot (2008), Insect Prey Consumed by a Bachelor Colony of Virginia Big-Eared Bats, Corynorhinus townsendii virginianus Handley, in Lee County, Kentucky, p. 65 
  13. ^ a b c Virginia Big-eared Bat (Corynorhinus townsendii virginianus) 
  14. ^ a b c Virginia Big-eared Bat 
  15. ^ a b Burford,Lacki, Habitat Use by Corynorhinus townsendii virginianus in the Daniel Boone National Forest 
  16. ^ Adam, Michael D., Foraging Areas and Habitat Use of the Virginia Big-Eared Bat in Kentucky 
  17. ^ Lacki, Adam, Shoemaker, Observations On Seasonal Cycle, Population Patterns, and Roost Selection in Summer Colonies of Plecotus townsendii virginianus in Kentucky 
  18. ^ Selbert, Pamela, Lockout for bats 
  19. ^ Lack, Justin B. (2009), A Relaxed Molecular Clock Places an Evolutionary Timescale on the Origins of North American Big-Eared Bats (Vespertilionidae: Corynorhinus) 
  20. ^ a b c Loab (2011), Conservation and management of eastern big-eared bats: a symposium 
  21. ^ a b c Bagley (1984), A Recovery Plan for the Ozark Big-Eared Bat and the Virginia Big-Eared Bat 
  22. ^ PIAGGIO (2008), Intraspecific comparison of population structure, genetic diversity, and dispersal among three subspecies of Townsend’s big-eared bats, Corynorhinus townsendii townsendii, C. t. pallescens, and the endangered C. t. virginianus 
  23. ^ Burford, Laura S., Moths Consumed By Corynorhinus Townsendii Virginianus In Eastern Kentucky 
  24. ^ Gordon (1997), Conservation Under the Endangered Species Act 
  25. ^ a b Blehert (2008), Bat White-Nose Syndrome: An Emerging Fungal Pathogen? 
  26. ^ http://www.whitenosesyndrome.org/news/north-american-bat-death-toll-exceeds-55-million-white-nose-syndrome
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Names and Taxonomy

Taxonomy

Comments: Formerly included in the genus Plecotus (see taxonomic comments for C. townsendii).

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