Washington Department of Fish and Wildlife Bats of Eastern Washington
[Bats]
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Our thanks and appreciation goes to the Bat Conservation International (BCI) and Merlin D. Tuttle for the following bat photos!

[Townsend Bat] Townsend's big-eared bat has large ears, 1.5 inches long, and pale cinnamon brown to dark brown fur. Total length is 3.5 - 4.5 inches. Females are usually larger than males. Townsend's  is another one of the "lump-nosed" bats, with large glandular masses like warts between the eyes.

This is a cave bat found most often around evergreen forests during warm months and less often in dry shrub-grassland. It is known to roost in limestone caves, lava tubes, and human-made structures; they are known to hibernate in mines and caves. Townsend's big-eared bat can fly at very low speeds, almost hovering in flight. They have been seen capturing insects - primarily small moths.

Pairs typically copulate between November and February. Sperm is stored in the reproductive tracts of females until spring. Gestation is between 56 - 100 days and birth occurs in late spring or early summer. Young bats grow rapidly, nearly reaching adult forearm size in one month. Females form maternity roosts in warm parts of caves, mines, and buildings. Males are solitary during this time.

In winter, Townsend's big-eared bats may hibernate singly or form clusters of up to several hundred. During hibernation, their ears may coil against the head to appear like rams horns. They do not migrate great distances and seem to come back to the same site year after year.

Townsend's Big-eared Bat

[Pallid Bat]The pallid bat is a large, 3.5-5.5 inch, pale, long-eared bat not easily confused with any other North American species. The eyes are large, and the nose has conspicuous glands which resemble wart-like bumps. The body color varies from pale cream-colored to light brown. The pallid bat is a species of the Columbia basin desert and grasslands habitats. It is gregarious and tends to form colonies in human-made outbuildings and other structures (such as culverts). This species tends to form small colonies and may use rock crevices as day roosts. Males and females usually form separate colonies throughout the summer.

Mating and copulation takes place from October through perhaps February. Sperm are stored by the female and ovulation and fertilization occur in spring. One young is born per female usually in May or June. Newborn remain attached to the teat until the female leaves to forage. The female returns often through the night to feed her young. A strong bond exists between mother and offspring and this association may continue for many years. Lactation occurs from May to mid-August and growth of the young is rapid.

Pallid bats are unusual because they can crawl and climb well and feed primarily on the ground eating crickets, grasshoppers, beetles, and spiders. Aside from excellent echolocating, pallid bats have good eyesight and a strong sense of smell. Rustling and other sounds generated by insects help these bats locate their prey. The range of the species covers much of North America, including Alaska, Quebec, and central Mexico.

The little brown myotis is a medium-sized, 3.5 inch, bat with small dark ears. It is usually found in or around our ponderosa pine woods. Nursery colonies have also been found among cottonwoods, willows, and sycamores. They are often found near permanent water. The little brown myotis has been "the bat" for many studies so there is much information about its form and function, reproduction, ecology, and behavior.

They have three types of roosts; day roosts, night roosts, and hibernation roosts called hibernacula. Day and night roosts are used by active bats in spring, summer, and fall, while hibernacula are used as overwintering sites. Little brown bat day roosts include sites in buildings, trees, under rocks, in piles of wood, and occasionally in caves. They gather in night roosts before feeding -  perhaps to increase roost temperature, deposit feces away from day roosts, or to reduce individual heat loss. When approaching a roost site, little brown bats make short circling flights. They use "honks" to avoid mid-air crashes with other bats. Their eyes perform better in dim light than in bright light. They spend a considerable amount of time each day grooming themselves. In winter, little brown bats hibernate usually in caves or mines.

These bats appear to consume whatever prey is in their path. In a captive study, a little brown bat was observed to eat 12 fruit flies per minute.

Pesticides have been blamed for the drastic decline of this and other bats. Exposure to pesticides kills bats either directly through exposure or indirectly through ingestion of sprayed insects.

Bat Sounds

The echolocation calls of most bat species are beyond the range of human hearing.
A bat detector, however, can make these signals audible to humans.

Our thanks goes to Bat Conservation International  for the following examples of bat echolations sounds.  An exciting new tape by Bat Conservation International takes you on a fascinating journey into the world of bat echolocation. The cassette contains calls of common North American bats, as well as natural history information for featured species.
Here are two samples from the audiotape:
[Note: Only the Silver-haired bat is found in Eastern Washington.]
[Silver-haired bat]
(150KB)		 Silver-haired Bat
with feeding buzzes.
Recorded by Burr Betts		 The "feeding buzz" is a distinctive feature of bat echolocation. Most hunting bats emit one echolocation pulse per wing beat. For a small bat, this is typically about 10 per second. When the bat detects an insect, it increases its pulse repetition rate up to roughly 200 per second, creating the "feeding buzz" we hear on a bat detector. This recording was made of a silver-haired bat as it caught an insect.
(© Merlin D. Tuttle, Bat Conservation International)
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[Silver-haired bat]
(164KB)		 Mexican
Free-tailed Bat
communication calls.
Recorded by Gareth Jones and John D. Altringham		 Bats also use a wide range of vocalizations to communicate. Many of these contain ultrasonic components that are above the human range of hearing. This broad-band recording was made at a large colony of Mexican free-tailed bats. This recording is slowed down by a factor of 10. The diversity of sounds illustrates the tremendous range of social communication. (Thanks again to Bat Conservation International for the sound files.)
(© Merlin D. Tuttle, Bat Conservation International)

Other Bat Photos

Spotted Bat Hoary Bat
Spotted Bat Hoary Bat

Bat Links

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