Eastern small-footed myotis

The eastern small footed bat is between 65 and 95 millimeters in length, has a wingspan of 210 to 250 millimeters, and weighs between 4 and 8 grams (with 4.0 to 5.25 grams being typical). The bat got its name from its very small hind feet, which are at most 8 millimeters long. A defining characteristic of this bat is its appearance of having a dark facial "mask", created by nearly black ears and muzzle. The fur on the dorsal side of their body is dark at the roots, and fades to a light brown at the tips, which gives the bats a signature shiny, chestnut-brown appearance. Like all bats, the eastern small-footed bat has a patagium that connects the body to the forelimbs and tail, aiding in flight. Their head is relatively flat and short, with a forehead that slopes gradually away from the rostrum, a feature that distinguishes them from other species in the Myotis genus. They have erect ears, which are broad at the base and a short flat nose. Like other Myotis, they have a pointed tragus. They also have a distinctly keeled calcar (cartilagenous rod on the hind legs to support the interfemoral membrane). The keeled calcar combined with their small forearms (less than 34 mm in length) can be used to distinguish them from all other Myotis in eastern North America. The tail is between 25 and 45 millimeters in length and protrudes past their interfemoral membrane. They have a dental formula of . Eastern small-footed bats are most likely to be confused with the little brown bat (Myotis lucifugus), especially in individuals where the face-mask is less apparent; however, forearm size less than 34 mm and presence of a keeled calcar are considered diagnostic. ==Range and distribution==

The range of this species includes northern Arkansas and southern Missouri, east to the Appalachian Mountains and Ohio River basin, south into northern Georgia, and north into New England, southern Ontario and Quebec. During the spring, summer, and autumn they predominantly roost at emergent rock-outcrops such as cliffs, bluffs, shale barrens, and talus slopes, but also man-made structures, including buildings, joints between segments of cement guard rails, turnpike tunnels, road-cuts, and rip-rap covered dams. The largest populations of Myotis leibii have been found in New York, Pennsylvania, West Virginia and the western part of Virginia. ==Diet==

Eastern small-footed bats are believed to feed primarily on flying insects such as beetles, moths, and flies They are nighttime foragers and usually forage in and along wooded areas at and below canopy height, over streams and ponds, and along cliffs. Moths compose nearly half of their diet, and they forage primarily on soft-bodied prey. ==Hibernation==

The eastern small-footed bat has been most often reported during hibernation, and has been counted at approximately 125 caves and mines. ==Spring and summer roosting==

in Virginia Compared to many other bat species, relatively little information about the spring and summer roosting locations of eastern small-footed bats is available. Summer roosts were previously considered difficult to find, but recent studies have shown that the species can be easy to locate if survey efforts are focused near appropriate rocky habitats. The species has also been documented roosting in or on buildings. On average they change their roosts every 1.1 days, and in one study males traveled about 41 meters between consecutive roosts and females around 67 meters. This study also found that females roosting sites were closer to ephemeral water sources than male's roosts. However, in another study on talus slopes in Virginia, males and female roosts appeared to be segregated on the basis of rock size. Reproductive females in Virginia roosted in boulders that were larger and more thermally stable than those used by males at the same sites. Temperatures in maternity roosts did not get as high as some male roosts during the day and they tended to retain more heat through the night, a microclimate likely beneficial to young bats that remain in the roost at night. Reproductive females and their young are sometimes observed congregated at the entrance to the roost, or even just outside the roost, likely to aid in thermoregulation. ==Mating and reproduction==

As with many other species of bats, the eastern small-footed bat usually has only one offspring a year, although a few instances of twins have been noted. This k-selected reproductive strategy means that their populations are not capable of withstanding high mortality rates, making them particularly vulnerable to sudden population declines. Mating most often occurs in autumn and the female stores the male's sperm throughout hibernation in the winter. Fertilization occurs in the spring once the females are active again, and gestation occurs between 50 and 60 days with young being born in late May and early June. The young's large body size is believed to lead to high-energy expenditure from the mother, which is what limits her to only having one offspring a year. Size of maternity colonies is not well studied, but they appear to form smaller groups than other bats in the genus. ==Threats==

The main threat to this species is habitat disturbance, both natural and human caused. They also likely are under threat from white-nose syndrome, pollution (especially water pollution) and human disturbance during hibernation. Very low levels of light, noise and heat are sufficient to wake hibernating bats. Once awake bats begin to expend energy and deplete critical fat reserves needed to survive winter. If disturbances within hibernacula are repeated, bats (especially juveniles) are likely to die. This phenomenon was well documented in other species of bats in eastern North America, such as the Indiana bat (Myotis sodalis) and gray bat (Myotis grisescens). White-nose syndrome (WNS) is a fungal infection that attacks bats while they hibernate. In the first six years following the discovery of WNS, 7 million bats of six different species were estimated to have been killed by the disease. Early estimates of impacts from white-nose syndrome based on bats counted in hibernacula suggested a 12 percent decline in eastern small-footed bat populations. However, changes in capture rates during summer, in West Virginia and New Hampshire, suggested declines from WNS may have been more severe (68–84%). Due to their dependency on exposed and predominantly non-forested rock outcrops for roosting sites, they may be at risk from "natural" processes such as forest encroachment and establishment of more mesic forest types due to suppression of forest fires. Likewise, the species is likely threatened by a host of human activities that impact rocky habitats or the surrounding areas where eastern small-footed bats forage, such as: mining, quarrying, oil and gas drilling and other forms of mineral extraction, logging, highway construction, wind energy and other forms of agricultural, industrial and residential development. However, it is also likely that some of the above activities have created roosting sites by providing exposed rock faces. ==Conservation==

The eastern small-footed bat is listed as endangered by the IUCN. Many states in the US in which the bat resides have begun listing it as threatened, and have begun conservation efforts in order to improve its numbers. In Canada, eastern small-footed bats are considered endangered in Ontario, and "threatened or vulnerable" in Quebec. The species is not protected under the US Endangered Species Act, but was a former C2 candidate for listing prior to the abolishment of that category by the U.S. Fish and Wildlife service in 1996. Some states (e.g. Pennsylvania) have given the species legal protection while others have recognized its apparently low numbers and consider the eastern small-footed bat a species of concern. In the report Species of Special Concern in Pennsylvania, the Pennsylvania Biological Survey assigned Myotis leibii the status of "threatened". Other states, such as Virginia, are currently working to get the eastern small-footed Myotis legal protection. Despite these efforts not many conservation projects have been initiated to help the species. Due to their cryptic hibernation patterns, and the lack of information regarding their spring and summer roosting sites, meaningful conservation efforts are difficult. The species will not usually use bat boxes like many other bat species, so construction of bat boxes is not an appropriate action to mitigate against habitat disturbance issues. However, the species is known to roost in man-made rocky habitats such as road cuts and rip-rap embankments, suggesting it should be possible to create roost sites for conservation purposes. ==Longevity==

The eastern small-footed bat has been recorded living up to the age of 12 years. ==See also==