Canyon Bat

Canyon Bat (Pipistrellus Hesperus), formerly known as the Western Pipistrelle.

Canyon Bat
Image Copyright (c) Merlin D. Tuttle

Description: Body length about 2.4-3.4″, with a 7-9″ wingspan. Yellow to light grey to reddish brown fur. Membrane of wings, ears and tail are dark black. Smallest bat in the US. Keeled calcar. One premolar. Club-shaped tragus (vs. pointed tragus of Myotis).

Range: Stays in home range. Hibernates or stays active. More common in desert and lowlands of south-western North America to Mexico. Found in association with significant rock features in lower elevation mixed conifer forest in mountain ranges in CA.

Habitat: Desert, around towns and above water. Roosts in rock crevices alone or in small groups, may also be found in mines and bridges. Begins foraging before sunset, may also be active after sunrise.

Diet: Caddis flies, stone flies, moths, small beetles, leaf and stilt bugs, leafhoppers, flies, mosquitoes, flying ants, wasps and fruit flies.

Behavior:Behavior: Strong, fast and erratic flier. Gives birth to twins which fly at 4 weeks.

Risks: Destruction of rocky areas due to mining and development.

Long-Eared Myotis

Long-Eared Myotis (Myotis evotis)

Long-Eared Myotis
Image Copyright (c) Merlin D. Tuttle

Description: Body length about 3.4-3.9″, with a 10-12″ wingspan. Long, glossy brown fur on back and lighter belly.

Range: Western US and Canada, not common in CA central valley. Probably migrates short distances to hibernate.

Habitat: Found in coniferous forested areas and semi arid shrub lands and agricultural areas. Roosts singly or in very small groups. Small maternal colonies. Roost in abandoned buildings, hollow trees, niches under bark, cliff crevices, caves and mines.

Diet: Emerges half hour after sunset. Forages in forests. Catches insects on the fly, gleans off vegetation or the ground. Prefers moths and beetles. Also consumes true bugs, flies, lace wings, other insects as well as spiders and wasps.

Behavior: Flies slowly, can hover. Mother gives birth to one pup. Life span 22 years.

Risks: Closure of abandoned mines, recreational caving, blasting for avalanche control, destruction of rocky areas for development.


Townsend’s Long-Eared Bat

Townsend’s Long-Eared Bat (Plecotus townsendii)

Townsend's Long-Eared Bat
Image Copyright (c) Merlin D. Tuttle

Description: Body length about 3.5-4.6″, with a 12-13″ wingspan. Pale to black fur with paler belly. Huge ears (over an inch long). Two lumps on either side of nose.

Range: Western North America. Hibernates in caves and mines near entrances.

Habitat: Forested and open (edge) habitat. Roosts from ceiling frequently hanging by one foot.

Diet: Emerge an hour after sunset. Eats mostly moths, but also eats lacewings, dung beetles, flies and sawflies.

Behavior: Flight can go from swift to hovering. One pup is born and able to fly at two and a half to three weeks. May lose half of the body mass during normal over-winter hibernation. Life span 16 years or more.

Risks: Habitat loss, vandalism, renewed mining and increased disturbance by cavers in maternity and roost colonies have reduced the numbers of this gentle bat. When roost is disturbed, they may abandon it permanently. Disturbance during hibernation leads to burning energy in an attempt to escape and they may not have enough fat storage left to survive the winter. Species of Special Concern in California.

Western Mastiff Bat

Western Mastiff Bat (Eumops parotis)

Western Mastiff Bat
Image Copyright (c) Merlin D. Tuttle

Description: Body length about 6.3-7.4″, with a 21-23″ wingspan. Bi-colored fur,  white at base and brownish to dark gray at tips with lighter underside. Largest bat in the US. Tail extends beyond tail membrane. Long narrow wings. Large round ears which bend forward and join at base.

Range: Southwest US. Does not migrate or hibernate.

Habitat: Desert scrub to woodland. Forage in open areas. Roost in exfoliating rock slabs of vertical cliffs and rugged canyons. Live deep inside narrow crevices. Sometimes roost with other species.

Diet: Emerge after complete darkness. Forage at high altitudes. Primarily eats moths but diet also includes beetles, crickets, katydids and dragonflies. May forage in groups.

Behavior: Due to size, drops 10 feet to launch flight. Fast, strong, high flier. Males and females roost together year-round. Birth one pup. Throat gland secretes strong odor. Emits high pitched sound audible to humans.

Risks: Urban expansion, disturbance, vandalism, quarry operations and rock climbing.
Species of Special Concern in California.

Fringe Tailed Bat

Fringe Tailed Bat (Myotis thysanodes)

Fringe Tailed Bat
Image Copyright (c) Merlin D. Tuttle

Description: Body length about 3.2-4.0″, with an 11-13″ wingspan. Reddish brown to dark brown long fur on back, paler underside. Small bat with relatively long ears. Fringe hair on tail membrane between feet.

Range: Western US and Canada. Patchy distribution and uncommon. May migrate to lower, warmer elevations and stay somewhat active in winter.

Habitat: Found in desert scrub to oak and juniper forests . It is most common in drier woodlands. Flies close to tree canopy and forages along streams and rivers. Roosts in rock crevices, caves, buildings and mines as well as large snags generally in small clusters of females. Males roost alone or in small separate colony.

Diet: Emerges one-two hours after sunset. Eats mostly beetles and moths, also consumes flies, leafhoppers, lacewings, crickets and spiders. May glean insects from foliage.

Behavior: Slow and agile flight. Can hover. Changes roosts periodically. One pup which can fly at 3 weeks of age.

Risks: Loss or modification of roosting habitat, mine changes, recreational caving, loss of decadent trees, removal of forest and woodland habitat.

Species of Special Concern in California.