C. townsendii can be distinguished from all other western bat species by the combination of a two-pronged, horseshoe-shaped lump on the nostrils, and large, rabbit-like ears. Although there are other western species with long ears none of these have the two-pronged nose lump, and most can be distinguished by other features.

1995: C. townsendii was listed as a species of Undetermined Status by Colorado Division of Wildlife.

1996: Because of its extreme sensitivity to human disturbance, vandalism of roost caves by recreationists, and its low reproductive rate, the Townsend's big-eared bat was listed as a Federal Species of Concern, requiring special protection.

Townsend's big-eared bat occurs through much of western North America. Since the species is limited by the presence of relatively rare habitat, it is regionally rare, but can be abundant where it occurs. Although the species is quite sedentary, its characteristics of late flight in the evenings, avoidance of humans, and ability to avoid capture may allow this bat to remain undetected in areas unless roost sites are located. Current known historical records for C. townsendii from Colorado number only about 200 individuals. Of these, 97 are from 1990 or later. Little is known of historical roost sites in the state.

 In terms of dominant vegetation type, this bat occurs in a variety of habitats, including desert scrub, sagebrush, chaparral, deciduous and coniferous forests. Their distribution is strongly associated with the availability of caves or cave-like roosting habitat such as old mines. In general, the most serious factor leading to population declines in bats is loss and/or disturbance of suitable roosting habitat, and Townsend's big-eared bats appear to be among the most dependent of all North American bats on abandoned or inactive mines. Concentrations also occur in areas with substantial surface exposures of cavity forming rock such as limestone, but such areas are rare in the West. The species is occasionally found in old, mostly abandoned buildings and other human made cave-like structures, but these areas are mostly used at night while the animals are foraging. The bats are inactive during the day, and stay mostly in caves or mine tunnels.

 These bats require habitat for day roosts, night roosts, and hibernation roosts. The most significant roosts, which have the largest aggregations and are most critical to the survival of populations, are the winter hibernacula (both sexes), and the summer maternity roosts (entirely adult females and their young).Additionally, there are other summer roosts: Those used in the day time by males and non-reproductive females (usually containing no more than a few animals per roost), night roosts (generally at a different site than the day roost), used by both sexes as a place to rest and digest food during the night, and interim roosts (sites used in the spring before the young are born and in the fall before moving to hibernating sites.

 During hibernation, the bats coil their ears tightly against their bodies like rams horns as shown in the left picture below.. Normally, their ears are unfurled as shown in the picture at right.

The wing and tail membranes also cover their bodies, and provide an insulating cover. In general, C. townsendii individuals begin to arrive at hibernacula in October and reach maximum numbers in January. If temperatures near hibernacula entrances drop below freezing, bats may arouse and move into the deeper, more stable parts of caves and mines. Recorded temperatures in C. townsendii hibernacula range from -2.0 degrees C to 13.0 degrees C, with temperatures below 10 degrees C preferred. Studies in the western U.S. have shown that Townsend's big eared bat selects hibernation roosts with stable, cold temperatures, and moderate airflow. Hibernacula with the appropriate stable temperature and humidity may be a major factor in limiting populations of the species. 

The Townsend's big eared bat requires roosting habitat that is inaccessible to humans, because individuals roost on walls or ceilings, often near entrances. They rarely seek shelter in crevices as many other bat species do. If undisturbed, individuals will frequently roost less than 3 meters off the ground, and have been found in air pockets under boulders on cave floors. Populations of this species are threatened by habitat loss, vandalism, and disturbance by cave explorers at maternity and hibernation roosts. Human disturbance can cause permanent abandonment of roost sites. Within a few years of publication of a guidebook to the caves of Colorado, human visitation to one particular cave increased so much that the colony of C.townsendii found there eventually disappeared.

 Females form separate maternity colonies in warm sections of caves or mines; warmth is essential for reproductive success. Fertilization is delayed after copulation in winter, and females give birth to one young in late spring and summer. Females become sexually mature at 2-3 years, and are polyandrous (1 female, many males) with no pair bonding. Gestation is 50-60 days. Young develop rapidly, and are capable of flight within three to four weeks.

 The big-eared bat feeds on moths, caddisflies, and other insects, detecting them by echolocation, and capturing them in flight. They forage frequently over water, and also pick insects from leaves. This bat is particularly maneuverable in flight, varying from swift darting movements to slow deliberate and hovering moves. This makes the species difficult to capture, which is one reason why so little is known about locations in Colorado. Townsend's big-eared bats are late flyers. They emerge from the roost primarily after dark, an average of 45.5 minutes after sunset, and forage until the early morning hours.

 Mortality is high among juveniles. The number of yearling females returning to their natal roost after their first winter averages 38% to 54%. After the first year the survival rat is around 80%. The average age of animals in a population is five years, although there has been a recovery of a previously banded individual >21years old. Undisturbed populations tend to remain stable, but low reproductive potential, high longevity and high roost fidelity make populations of this species highly sensitive to roost threats. During hibernation, both males and females lose roughly half of their body weight, and arousal from winter hibernation can lead to the expenditure of roughly 10 to 30 days' supply of fat reserves. This can lead to starvation before the arrival of spring when food supplies again become abundant. Loss and/or degradation of foraging habitat may also be a contributing factor in the declines of C.townsendii populations.

An additional threat is the closure of abandoned mines by private landowners or by claim and patent holders.  Historic underground workings (shafts, adits, stopes, etc.) can also become incorporated into current open pit mining plans of operation. Eventually, older hard rock mines are shaved away by the newer open pits. C. townsendii roosts have been lost under these circumstances. At times, limestone solution caves were incorporated into the workings of historic hard rock mines. Open pit mining in these sites could destroy natural caves as well.

Experiments in West Virginia have shown that excluding humans from roostsites by gating or fencing has resulted in increases in C. townsendii populations. When gates have been breached, populations have dropped precipitously, and been slow to recover. C. townsendii populations have been negatively impacted by the increasing popularity of recreational caving. Public land cave locations are often included on agency maps that are dispersed to the public. The USGS has traditionally included cave locations on the 7.5 minute series (topographic) maps. Cave locations have been freely dispensed upon inquiry to civic groups, the media, and the general public. These factors, together with improved and increased road networks, have made many caves with bat habitat easily accessible to the general public, thus increasing roost visitation and potential harassment. Some elements of the caving community have observed agency cave management and have withheld information about cave locations or cave resources out of fear of increased regulation or poor management. Barriers to communication between cave managers and cave user groups could contribute to further losses in bat habitat. Research activities can also depress, scatter, or extirpate populations of C. townsendii. For some of the same reasons that recreational caving can have a negative impact on this species, increased roost visitation by scientists can have similar effects.

Chemicals produced by humans are another source of mortality for the Townsend's big eared bat. Cyanide is used in the processing of gold ore. A cyanide solution is sprayed on gold bearing ore and later collected in ponds of varying size. These ponds often contain lethal levels of cyanide and heavy metal compounds. In Nevada, 15 mines reported killing at least 158 bats (species not identified)between _ 1986 and 1989 in their cyanide solution ponds (NDOW Files).Regulations designed to eliminate this source of mortality through netting and neutralization were established in April 1990 and reported mortalities decreased significantly as a result. A troubling unknown is how many of these mortalities go undetected and thus unreported; particularly those mortalities that result from bats using ponded water atop ore piles. Also, as before mentioned, much of the contemporary open pit gold mining in the west is associated with historic mining Districts. Locating toxic water sources in close proximity to established C.townsendii roost sites may be a deadly consequence of these associated land uses. Locating oil reserve pits (associated with oil drilling operations) near roost sites can also be a source of bat mortality. C.townsendii forages primarily on moths. Non-target, insecticide sprays reduce the number and quality of insects in an area available to C.townsendii and have been identified as contributing to the decline of North American bat populations.

 Abandoned mines must be evaluated as bat habitat prior to closure. Identified roosts will receive protection consistent with the goal of this conservation strategy. Any gates must meet design specifications, allowing exit and entry by the species of concern while blocking entry by humans. Agencies will cooperate with private owners possessing mines. Cave roosts of all types must be identified (e.g. maternity, etc.), and detailed restrictions for use of inhabited caves must be put in place. Where applicable, protection will include gating, public education/outreach, law enforcement, area/trail/road closures, visitor use management. Agencies Management Practices will cooperate with private land owners possessing caves. Information regarding locations of caves will be restricted under the Federal Cave Resources Protection Act, and printed locations will be removed from maps, brochures, and other public flyers. Caving clubs will be encouraged to keep inhabited cave locations confidential. Important caves will be designated as Areas of Critical Environmental Concern (ACEC) and/or Research Natural Areas (RNA) on BLM and USFS managed lands. The Federal Cave Resources Act of 1988 will be used for guidance in management decisions.

URL:http://www.fw.vt.edu/fishex/nmex_main/species/050025.htm (information about Townsend's big eared bat)

URL:http://birding.miningco.com/msubbats.htm (general information about bats: bat houses, bat detectors, etc)

http://www.marshill.org/Apologetics%20Pages/bat_sonar.htm  (the amazing precision of bat sonar!)

http://www.batcon.org/ptown.html (Bat Conservation International)