Bats

Chiroptera

Townsend’s big-eared bat © J. Scott Altenbach.

There are more than 1,100 different species of bats, representing 20% of all mammal species worldwide. At least twenty of these bat species are found in the Los Padres National Forest. However, their numbers have dwindled and more than two thirds of bat species in the region are imperiled. Protecting remaining bat populations is important because of their vital role as insect controllers, pollinators, and seed scatterers.

Bats vary widely in size — the smallest mammal in the world is the bumblebee bat of Thailand (smaller than a dime), while some of the fruit bats (also known as “flying foxes”) of the Asian tropics can have a wingspan of up to six feet. Their shape also varies between species and usually corresponds with food type and highly specialized hunting or foraging habits. For instance, certain insect-eating bats that feed over water have very different feet, wings and ears than bats that catch insects in mid-air. Contrary to popular belief, more than 70% of bats eat insects, with much of the remainder being tropical species that feed on fruit and nectar. A few are carnivorous, eating small fish, birds and frogs. Only three species of bat are vampiric, totally subsisting on blood, and they are only found in South America. Sadly, bats all over the world have been targeted by humans based upon an unfounded fear that they are vampire bats when really they eat insects or fruit.

Bats are the only truly flying mammal species. This is part of the reason that they roost upside-down; because they don’t have the strength, like birds, to launch themselves into flight from standing, they drop from a hanging position directly into flight. Hanging upside-down also allows them to rest safely away from predators. Some bats are solitary and travel and roost alone or in small groups, while others prefer to congregate in large colonies of millions of bats. They are a commuting, migratory species, meaning they move from place to place on a nightly basis from a few to hundreds of miles. Like humans, bats give birth to live, helpless young and breast feed them on milk for several months, making them, for their size, the slowest reproducing mammals on earth. They are also quite long-lived for their size—some species can live into their thirties!

Bat sonar (formally called echolocation) is perhaps the most unique bat trait. Like dolphins, bats emit pulses of extremely high frequency sound waves, which bounce back to them as echoes and allow them to form an image of their surroundings. Most bats even have relatively good eyesight, but use this technique to navigate and hunt. Bat sonar is so efficient that they can snatch flying insects from the air and navigate past objects as small as a string in complete darkness.

Bat Species

Within the Los Padres National Forest, bat species vary from “mouse-eared” bats (from the genus Myotis) to the very large western mastiff bat. Conservation issues mainly have to do with the availability of adequate roosts (usually trees or caves) and feeding habitat within the distance of the nightly commute to a new roost. The large scale urban development surrounding the southern portions of the Los Padres limits bat survival in many areas, and therefore looking at the entire landscape’s interactions to inform conservation is vital.

Following are further descriptions of bat species found within the Los Padres National Forest that are classified as Federally Endangered (FE), Federal Species of Concern (FSC), California Species of Special Concern (CSC), Forest Service Sensitive (FSS), Bureau of Land Management Sensitive (BLM), or any combination thereof.

Fringed Myotis (Myotis thysanodes) – FSC, CSC, BLM

Photo © J. Scott Altenbach.

Fringed myotis is a large “mouse-eared” bat, with its name referring to a fringe of short hairs on the edge of the membrane between its hind legs. It can be found from sea-level to above 6,400 feet across its general range from British Columbia to Mexico, but is restricted to high-elevation habitats in southern California. In the Los Padres, it was found only at high elevations above 4,600 feet and populations are very patchy throughout the forest. Little is known about its history in this area, but it is actually thought to have always been a rare species in the Los Padres. Fringed myotis eats mostly insects such as crickets, moths and daddy longlegs, and roosts mostly in rock crevices and buildings.

Long-Eared Myotis (Myotis evotis) – FSC, BLM

Photo © J. Scott Altenbach.

Long-eared myotis is also a member of the “mouse-eared” bat genus, and has very long ears that are narrower than those of other myotis. This bat, like its relative the fringed myotis, can only be found throughout the upper elevations of the Los Padres, usually in oak woodlands. The long-eared myotis eats mostly moths, flies and beetles. It usually roosts in hollow trees, under slabs of bark or in abandoned mines, so timber harvesting and the sealing of mine entrances are harmful to its survival. However, a common technique is to seal mine entrances with “bat-friendly” gates that allow bats access to the caves, but keep humans and larger animals out.

Long-Legged Myotis (Myotis volans) – FSC, CSC, BLM

Photo © J. Scott Altenbach.

Long-legged myotis is the Los Padres National Forest’s third threatened member of the “mouse-eared” genus. It can be recognized by its short ears, long tail and relatively large hind feet. It occurs mostly in the high-elevation woodlands of the Los Padres and roosts in hollow tree snags or lightning scars during the day, and caves or mines at night. Although the long-legged myotis, like the fringed myotis, is likely to have always been rare in this area, timber harvests, pesticides, and mine reclamation activities are harmful to its survival. Its diet consists mostly of moths, termites, beetles and flies.

Pallid Bat (Antrozous pallidus) – CSC, FSS, BLM

Photo © J. Scott Altenbach.

Pallid bat is a small, pale colored bat with large eyes that has very unique feeding habits: it feeds mostly on insects from the ground, while most other insect-eating bats capture food from the air. It is known to eat scorpions (it is immune to their sting!), spiders, praying mantids, and grasshoppers and has even been seen running across the ground chasing crickets. Pallid bats are found at high elevations between 1,100-6,600 feet within the Los Padres. There is strong evidence to suggest that the pallid bat has suffered severe population declines in recent years in our region due to the destruction of roosting sites (human structures, mines, tree hollows). It is extremely dependent upon its roosts for survival, and the large scale of roost disturbance in this region may cause populations to fail in the future.

Townsend’s Big-Eared Bat (Corynorhinus townsendii) – CSC, FSS, FSC, BLM

Photo © J. Scott Altenbach.

Townsend’s Big-Eared Bat, so named for its extremely large ears, is found throughout the Los Padres. Its distribution, however, depends upon the availability of caves or abandoned mines due to its large size and preference to live in large colonies. Its ability to survive also depends on these types of roosting sites, and its numbers are in decline due to disturbance of its reproductive roosts. These disturbances include mining, sealing of abandoned mines, vandalism and recreational use of caves. Recommended conservation efforts include protection of key roosting sites and close monitoring of population numbers.

Western Mastiff Bat (Eumops perotis californicus) – CSC, FSC, BLM

Photo © J. Scott Altenbach.

Western mastiff bat’s home range extends through all of California, but its greatest concentration historically was in southern California. It is the largest bat native to North America, with a wingspan of almost 2 feet, and is characterized by its enormous ears that are joined at the base and extend over each side of its head like a bonnet. It usually roosts in rock crevices and large rock outcroppings on cliffs that have an opening of at least 6.5 feet to allow them to drop in from flight. The western mastiff bat is very dependent on wide-open spaces for foraging for moths, its main food source, and is affected by the limitation on foraging that urban development causes.

Western Red Bat (Lasiurus blossevillii) – CSC, FSS

Photo © J. Scott Altenbach.

Western red bat is a solitary species that roosts alone or in small groups mainly in shrubs and small trees in habitats bordering rivers, forests and urban areas. It has been documented along the upper Salinas River in the Los Padres National Forest. The western red bat is also a migratory species, ranging from Canada to South America, only spending its summers in southern California and the Los Padres National Forest before migrating southwest. Because of its migratory nature, the western red bat is very dependent upon the connectivity of habitat along its migratory pathway and has probably suffered decline due to habitat loss from urban expansion, reservoir construction and agricultural conversion.

Bats of the Los Padres National Forest

  • Pallid Bat (Antrozus pallidus)
  • Mexican long-tongued bat (Choeronycteris mexicana)
  • Townsend’s big-eared bat (Corynorhinus townsendii)
  • Big brown bat (Eptesicus fuscus)
  • Spotted bat (Euderma maculatum)
  • Western mastiff bat (Eumops perotis)
  • Red bat (Lasiurus blossevillii)
  • Hoary bat (Lasiurus cinereus)
  • Silver-haired bat (Lasionycterus noctivagans)
  • California leaf-nosed bat (Macrotus californicus)
  • California myotis (Myotis californicus)
  • Western small-footed myotis (Myotis ciliolabrum)
  • Long-eared myotis (Myotis evotis)
  • Fringed myotis (Myotis thysanodes)
  • Long-legged myotis (Myotis volans)
  • Yuma myotis (Myotis yumanensis
  • Pocketed free-tailed bat (Nyctinomops femorosaccus)
  • Big free-tailed bat (Nyctinomops macrotis)
  • Western pipistrelle (Pipistrellus hesperus)
  • Brazilian free-tailed bat (Tadarida brasilienis)

Fun Facts

  • There are at least twenty different species of bats in the Los Padres National Forest – from the small mouse-eared bats to the very large western mastiff bat.
  • Most bats eat only insects, fruits, and/or nectar.
  • Bats drop from a hanging position directly into flight – unlike birds, they don’t have the strength to launch into flight from standing.
  • Some bats are solitary and roost alone or in small groups, while other species prefer to gather in large colonies of millions of bats!
  • Bats are long-lived for their size – some can live into their thirties!
  • Bats emit high-frequency sound waves to navigate and hunt. They also have good eyesight.
  • North America’s largest bat, the western mastiff bat, is found in the Los Padres National Forest. It’s wing span is nearly two feet!