Myotis volans

"Long-legged myotis typically occupy mountainous or relatively rugged areas. They often live in coniferous forest, although they are sometimes found in oak or streamside woodlands, and even deserts. They feed mostly on moths, but are opportunistic, eating whatever soft-bodied insects are most abundant. When several long-legged myotis are feeding in the same area, and two bats seem to be on a collision course, they alter their echolocation calls, adding a lower-frequency ""honk."""

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Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Range includes western North America from southwestern Alaska, British Columbia, and Alberta south to Baja California and central Mexico (Jalisco, Veracruz, Nuevo Leon). This species occurs throughout the western United States from the Pacific coast to western North Dakota and extreme western Texas (Barbour and Davis 1969, Western Bat Working Group 1998, Bat Conservation International 1998, Adams 2003, Reid 2006).

Jalisco to Veracruz (Mexico); Alaska Panhandle (USA) to Baja California (Mexico), east to Northern Nuevo León (Mexico), South Dakota (USA), and Central Alberta (Canada) (Simmons 2005).

Long-legged Myotis are distributed throughout much of western North America, from central Mexico to southeastern Alaska and western Canada (Keller, 1987; Nagorsen and Brigham, 1993).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Myotis volans range from 83 to 100mm in total length with a wingspan from 215 to 272mm. Fur color varies from reddish-brown to nearly black with the ventral fur being relatively dark. The ventral fur extends onto the underside of the wing to a line joining the elbow and knee. The ears are relatively short (9 to 15mm) with rounded tips and barely extend to the nose when pushed forward. The tragus is long (5 to 7mm) and narrow. The calcar bears a prominent keel and the third metacarpal is longer than the fourth and fifth. The common name is derived from its relatively long tibia and the feet are relatively small. Characteristics of the skull include a short rostrum, steep forhead, broad interorbital region, and globose brain-case. Dental formula is 2/3 1/1 2/3 3/3.

Range mass: 5 to 10 g.

Range length: 83 to 100 mm.

Other Physical Features: endothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

Length: 10 cm

Length:
Range: 76-106 mm

Weight:
Average: 7.5 g
Range: 5-10 g

Habitat and Ecology

Systems

• Terrestrial

M. volans are found in forested regions. They establish roosts in trees, rock crevices, fissures in stream banks, and buildings. Caves and mines are not used in the day, but M. volans can be captured there at night (van Zyll de Jong, 1985).

Terrestrial Biomes: forest

Comments: Primarily in montane coniferous forests, in the south most often at 2000-3000 m; also riparian and desert (Baja California) habitats. May change habitats seasonally. Uses caves and mines as hibernacula, but winter habits are poorly known. Roosts in abandoned buildings, rock crevices, under bark, etc. In summer, apparently does not use caves as daytime roost site. In some areas hollow trees are the most common nursery sites, but buildings and rock crevices are also used. See Vonhof and Barclay (1996) for information on characteristics of roost trees in British Columbia.

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.

Adults and young leave the maternity colonies in fall but nothing is known of their subsequent movements (Barbour and Davis 1969).

Emerging at dusk and staying active throughout the night, M. volans takes aerial prey 3 to 4 meters over water, forest clearings, and forest canopy. Their diet consists mostly of moths (75%), but they also feed on termites, spiders, flies, beetles, leafhoppers, and lacewings. The echolocation call consists of a shallow frequency modulated sweep. They are capable of detecting prey at a distance of 5 to 10m. When foraging they follow a repetitive circuit throughout the evening and on consecutive nights (Barbour and Davis, 1969; Nagorsen and Brigham, 1993; Wilson and Ruff, 1999; van Zyll de Jong, 1985).

Comments: Feeds primarily on moths. Also consumes a wide variety of invertebrates: fleas, termites, lacewings, wasps, small beetles, etc. (Warner and Czaplewski 1984). Follows prey for relatively long distances around, through, over forest canopy, forest clearings, and over water. In New Mexico, forages primarily in open areas, feeds mainly on small moths (Black 1974).

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

Estimated Number of Occurrences: 81 to >300

Comments: This species is represented by a large number of occurrences (subpopulations). For example, Verts and Carraway (1998) mapped approximately 70 collection sites in Oregon, Hoffmeister (1986) mapped 34 sites in Arizona, and the species is known from several dozen recently documented sites in Montana (http://fieldguide.mt.gov/detail_AMACC01110.aspx).

100,000 to >1,000,000 individuals

Comments: Total adult population size is unknown but apparently quite large (likely greater than 100,000). According to Tuttle and Taylor (1994) mine colonies are usually in the hundreds and mines can be used year-round. About 700 specimens have been collected in New Mexico (Geluso et al. 1987). In Arizona, this species forms large nursery colonies, often numbering in the hundreds (Arizona Game and Fish Department 1997). Based on an extensive 1997 survey, the Nevada Heritage Program estimates at least 600 individuals in Nevada (Carrie Carreno, pers. comm., 1998). The Washington Heritage Program estimates more than 1,000 individuals and possibly more than 100,000 individuals in Washington State (John Fleckenstein, pers. comm., 1998).

In many areas this Myotis may be the most abundant species; it is the common Myotis in the western U.S. Life span of 21 years recorded in the wild.

Comments: Active throughout most of the night. Peak activity occurs during the first 3-4 hours after sunset (Warner and Czaplewski 1984).

Average lifespan
Sex: male
Status: wild: 2.1 years.

Maximum longevity: 21 years (wild)

Large nursery colonies, which may number in the hundreds, are formed by this species. These colonies occur most commonly in trees. Mating occurs before the bats enter hibernation in late August or September. Mature females produce one offspring, although it is unknown at what age sexual maturity is reached. Time of parturition varies with latitude. Young are born in late June and July. It is speculated that most juvenile males are sexually active. Banded individuals have been recorded living to 21 years of age (Barbour and Davis, 1969; Nagorsen and Brigham, 1993; van Zyll de Jong, 1985).

Range number of offspring: 1 to 1.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous ; sperm-storing

Average number of offspring: 1.

Average age at sexual or reproductive maturity (female)
Sex: female: 152 days.

In New Mexico, copulation was noted to begin in late August; sperm stored overwinter in female reproductive tract; ovulation occurred March-May, parturition May-August (Black 1974). Births probably occur in June or early July in Texas (Schmidly 1991). Litter size: 1. Nursery colonies may include up to several hundred individuals.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 7
Species With Barcodes: 1

Rounded Global Status Rank: G5 - Secure

Reasons: Widespread distribution in western North America; apparently large number of populations; considered locally abundant; probably secure throughout much of range.

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 1996
  Lower Risk/least concern
  (Baillie and Groombridge 1996)

Temperate North American bats are now threatened by a fungal disease called “white-nose syndrome.” This disease has devastated eastern North American bat populations at hibernation sites since 2007. The fungus, Geomyces destructans, grows best in cold, humid conditions that are typical of many bat hibernacula. The fungus grows on, and in some cases invades, the bodies of hibernating bats and seems to result in disturbance from hibernation, causing a debilitating loss of important metabolic resources and mass deaths. Mortality rates at some hibernation sites have been as high as 90%. While there are currently no reports of Myotis volans mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N5 - Secure

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

Comments: Range-wide population trends are unknown (Western Bat Working Group 1998), but distribution and abundance probably are relatively stable Populations are considered stable by heritage programs in Arizona, Nevada, Washington, and Nebraska (Arizona Game and Fish Department 1997, Carrie Carreno, John Fleckenstein, and Mike Fritz, pers. comm., 1998). Populations in Wyoming are greatly restricted or declining (Mary Neighbours, pers. comm., 1998).

Population

Population Trend

Degree of Threat: C : Not very threatened throughout its range, communities often provide natural resources that when exploited alter the composition and structure over the short-term, or communities are self-protecting because they are unsuitable for other uses

Comments: Overall, no major threats are known. Locally, this bat may be affected detrimentally by the closure of abandoned mines without adequate surveys, disturbance by humans, and certain forest management practices. As of mid-2012, this species was not known to be affected by white-nose syndrome.

Human disturbance can be extremely detrimental to bat colonies in general, especially to nonvolant young and hibernating adults (New Mexico Department of Game and Fish 1997). Special precautions should be taken when mine and cave surveys are conducted during breeding periods and winter hibernation. Disturbance of breeding colonies can cause young to lose their grasp and fall to their death. Disturbance during hibernation can cause bats to use up stored fat reserves and starve to death.

Residues of DDT and its metabolites have been found in Oregon individuals (Western Bat Working Group 1998).

According to Heritage Programs, the degree of threat is considered moderate in Oregon and Sonora (Mexico), and not very threatened in Nebraska, Washington, and Nevada (Eleanor Gaines, Andres Villareal Lazarraga, Mike Fritz, Carrie Carreno, and John Fleckenstein, pers. comm., 1998).

Major Threats

Global Protection: Many to very many (13 to >40) occurrences appropriately protected and managed

Comments: Many occurrences are in protected areas.

Conservation Actions

There are no known negative effects of M. volans, though bat populations do sometimes act as disease vectors.

M. volans populations act to control insect populations, as do those of other bat species.