Clumps of Spanish moss make good daytime roosting places for northern yellow bats. Small groups of males or slightly larger groups of females are often found roosting together in forested areas near a permanent source of water. They are seldom found roosting in houses or other manmade structures. They feed over open spaces: they are seen over golf courses, beaches, and along the edges of ponds, hunting for mosquitoes, flies, and other insect prey. Barn owls are known to prey on them. Unlike most other Lasiurus bats, they have only two nipples, and if a female gives birth to more than two offspring, usually only two survive. Young are born in May or June and are flying by June or July.

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This species occurs from Honduras to Sinaloa (Mexico) and through Texas to Florida and New Jersey (USA) (Simmons, 2005). It occurs from lowlands to 1,600 m (Reid, 1997). Found in Costa Rica.

Lasiurus intermedius is found only in the United States of America, with a range spanning along the southern coastal plains of the Atlantic and the Gulf of Mexico. The Northern Yellow Bat is found from Virginia down to Florida and to the Southern tip of Texas, as far inland as Austin. (GA Museum of Natural History, 1999).

Biogeographic Regions: nearctic (Native )

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

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Coastal southeastern U.S. from South Carolina (with records north to Virginia) south to Florida, west along Gulf Coast to south-central Texas, and southward to Honduras, north to southern Sinaloa in western Mexico. Extralimital record from New Jersey. The formerly included Cuban population was found by Morales and Bickham (1995) to be a distinct species (L. INSULARIS).

Lasiurus intermedius gets its name from its yellow-orange to yellow-brown fur. It has long, silky fur only on the anterior half of its dorsal surface. The body is ventrally compressed and it has a short neck. The underside and its thin, wing membrane (patagium) are nearly naked. It has elongated hands, each with a thumb and four fingers. These elongated metacarpal and phalanges bones help to spread and control the wings. The hip joint in rotated 90 degrees--the legs project sideways and the knees are almost backwards. This formation is thought to assist the bats when alighting upside down and hanging by their toes. The length of the maxillary toothrow is usually more than 6.0 mm. The females are larger than the males (a sexually dimorphic species). The average total length of the Northern Yellow Bat is approximately 118-129 mm.

(Allen, 1997; GA Museum of Natural History, 1999; Simmons, 1999; Taylor).

Range mass: 17 to 22 g.

Length: 13 cm

Sexual Dimorphism: Females are larger than males.

Length:
Range: 121-131.5 mm

Weight:
Average: 17 g
Range: 14-20 g

Habitat and Ecology

Systems

• Terrestrial

Lasiurus intermedius primarily roosts in Spanish moss, Tillandsia usneoides, but it also uses trees--often dead palm fronds. It generally inhabits hardwood and pine forests in permanent water, but is also found in pine groves. One oak tree with Spanish moss may harbor several bats. (GA Museum of Natural History, 1999; Organization for Bat Conservation).

Terrestrial Biomes: forest

Comments: Typically occurs in wooded areas in the vicinity of permanent water. In the southeastern U.S., often roosts and rears young in clumps of Spanish-moss, commonly in longleaf pine/turkey oak sandhill habitats and live oak hammocks; in Florida, most abundant in dry uplands (Kern 1992). Sometimes roosts and rears young in the skirt of old fronds of tall palm trees or structurally similar sites. Rarely reported from buildings. Forages primarily over open areas such as fields, pastures, airports, golf courses, marshes and lake borders, and the open savanna-like habitat of sandhills (Jennings 1958). Often taken over water.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

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.

Does not appear to migrate in Florida and Louisiana.

Lasiurus intermedius is a nocturnal insectivore that locates its prey through echolocation. Specifically, the Northern Yellow Bat preys upon leafhoppers, dragonflies, diving beetles, ants, and mosquitoes. It forages over open, grassy areas, such as pastures, lake edges, golf courses, and forest edges. (Allen, 1997).

Comments: Typically forages for flying insects 15-50 feet above ground in open areas, above the canopy of a woodland, or along along forest edges. May form evening feeding aggregations (Florida).

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

Estimated Number of Occurrences: 21 to >300

Comments: No exact figures.

2500 to >1,000,000 individuals

Comments: Relatively common in preferred habitat.

Tends to roost singly, but may aggregate in the same tree. Evidently there is sexual segregation in winter (Webster et al. 1980).

Comments: Probably primarily nocturnal.

Lasiurus intermedius breeds in late fall; however, fertilization and embryo development do not occur until the following spring (specifically referred to as "delayed fertilization"). The females generally carry 3-4 embryos, but only 2-3 young are born. Birth occurs in late May/early June. The young are born naked and helpless with small and undeveloped wings, but they mature and grow rapidly and are generally able to take to flight by late June of the year they are born. The complete extent of the mating season and its reproduction is not fully understood. The females do not take the young out on nocturnal flights but may transport them if the daytime roosts are disturbed. (Allen, 1997; GA Museum of Natural History, 1999; UC Berkeley, 1995).

Range number of offspring: 1 to 4.

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

In Florida, mates in fall. Gestation lasts 2-3 months. In Florida, a litter of usually 3-4 is born in May-June; postpartum litter size usually is 2-3. In Florida, lactation may extend well into July, though some young are foraging by the first week in July. Young probably fly within one month. Forms small loose maternity colonies, sometimes including up to at least 45 individuals.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 2
Species With Barcodes: 1

Lasiurus intermedius is generally considered to be a rare bat, although it is common across the state of Florida. Its major population threat comes from the destruction of their habitats (forest trees, palms, etc.) by humans. (Department of Wildlife Ecology and Conservation, 1997).

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 Lasiurus intermedius mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America.

CITES: no special status

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: N4 - Apparently Secure

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: Large range (southeastern U.S. to Central America) and relatively common but dependent upon Spanish-moss or palm fronds for roosting sites; threatened by loss of wooded habitats suitable for roosting.

Population

Population Trend

Major Threats

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: Threats include habitat loss due to residential and citrus development. Reduced abundance of Spanish-moss due to fungus outbreak may be a problem. Formerly, human harvest of Spanish-moss was a problem, but that industry is no longer viable. Removal of old palm fronds may reduce potential roost sites in suburban areas.

Conservation Actions

Biological Research Needs: Investigate movements.

Global Protection: Unknown whether any occurrences are appropriately protected and managed

Needs: Protect preferred habitat by selective cutting of trees without Spanish-moss; reduce Spanish-moss harvest.

Bats, in general, have been known to roost in accessible attics or roofs. This can lead to an inconvenient economic "burden" that is limited to barring the entrance to the roosting site. Lasiurus intermedius , however, does not generally roost outside of a tree or a clump of Spanish moss.

Lasiurus intermedius provides a significantly greater benefit to humans than it does harm. By eating a large amount of insects, particularly mosquitoes, the bats eliminate potentially detrimental elements: insect consumption can reduce agricultural output, and insects (in particular, mosquitoes) can carry dangerous, and even fatal, diseases. (Taylor).

Comments: New World Lasiurus were placed in the genus Nycteris by Hall (1981), who based the change on nomenclatural (rather than biological) concerns; few if any other authors have followed this change. Included in the genus Lasiurus by Jones et al. (1992) and Koopman (in Wilson and Reeder 1993).

Prior to 1961, populations in the southeastern U.S. were regarded as a distinct species, L. floridanus.

Here the Cuban form is considered a distinct species, Lasiurus insularis (Webster et al. 1980, Rodriguez and Kunz 2002, Morales and Bickham 1995).

See Baker et al. (1988) for a genic analysis and information on the relationship to other Lasiurus. See Hall and Jones (1961) for a taxonomic evaluation of this species.