TN10032 SMALL-FOOTED MYOTIS MYOTIS LEIBII
Physical description: This is the smallest myotis in the eastern U.S.. It has a tiny foot, short forearm, flat skull and keeled calcar. It has long glossy/silky brown fur, and a facial mask, ears and black membranes. The total length is 73-82 mm, with a wingspread of 212-248 mm, and a weight from 1/5 to 1/3 ounce *152,20,219,141,45*. Reproduction: Little data is available. The single young are born May-July *20,141,45*. They don't form nursury colonies but are usually found alone *8905*. Behavior: The hardiest species are found in caves/mines of eastern North America. They have a characteristic slow flight and an extension of the arms about 30 degrees from vertical when hanging. They generally roost on the ground under rocks, in crevices/occasionally in buildings and under tree bark. It has been reported hanging in the open in West Virginia, and is not as often seen as an exposed ceiling-hanger. They may not migrate far if suitable hibernation sites are nearby. The last bat to hibernate was gone by February or March. It is active in late winter and hibernates in cold, dry areas near cave entrances (drafty, low humidity, may be subfreezing). They may pack tightly and deeply. In the summer this species molts and is out in the early evening to feed among trees, and overbrush, filling its stomach quickly *147, 152,286,20,2117,141,45*. They enter hibernation in November and may be active in late January or early February, but they resume hibernation when the temperatures drop again. They feed on mosquitoes anbd small beetles and fly faster than many similar species *8905*. Origin: This species is native *134,147,152,286,20,141*. Population parameters: This species may be rare in the state. The longevity record is 12 years *20,89*. Aquatic/terrestrial associations: They may be found in association with M. keenii in hibernacula *109*. Physical Description: The small-footed myotis can be distinguished from the little brown bat and other myotids by its small size and black facial mask. Overall, the color of this species is generally glossy brown, but varying shades of pale yellow or light tan to dark brown are known *20,90*. The face from nose to the base of the ears is black, including the lower lip and the ears *20,90,376,PA11369,45*. The wings (membranes) and interfe- moral membrane are dark brown, nearly black, and the calcar is keeled *20,90,45*. Other points aiding in identification are the small feet (<8mm), flattened skull, short forearm (30-36 mm), and wingspread (212-248 mm) *20,90,376,PA11498,5323*. Weights have been reported to average 5-8 gm (1/5 to 1/3 oz); however, adults may weigh as little as 3 gm *5323,45*. The total length is 69-88 mm and the hind foot length is 6 mm 20,45,141, 152,219,6037*. Reproduction: Very little data is available on the reproduction of this species. Very few maternity colonies have been reported and there have been only limited observations on summer roosts *20,5447*. Time of breeding, gestation period, pair bonds, breeding site, age of sexual materity, minimum and maximum breeding ages all are unknown *20,4771*. Apparently a single offspring is born, probable, sometime in May to July to adult females in summer maternity colonies *20,45,4771,PA11573*. Possible twinning was recorded at a recorded at a roost in South Dakota *5447*. In this case, both juveniles were males. Only one litter is produced each year *20,90*. Young, nonvolant (non-flying) juveniles are raised in nursery colonies. Colonies of 12-35 bats have been found in abandoned and little used buildings and in horizontal fractures on vertical walls or boulders *5447*. Behavior: Little is known of the behavioral characteristics of the small-footed bat, except for a few studies of hibernacular and roosting colonies. This species appears to be the hardiest bat species inhabiting the caves, mines, and tunnels of the eastern United States *204*. This bat is one of the last, if not the last, to move into hibernacula in the fall and one of the first to leave hibernacula in the spring. Small-footed myotis probably enter hibernacula sometime in late November and early December (December 1 is the earliest reported date in Pennsylvania) and depart hibernacula in late February, March, and early April (April 9 is the latest depar- ture date reported) *90,5323,PA11471*. This bat also appears to be active while occupying the hibernacula *PA11471,PA11567* and may move outside the hibernacula in moderately warm weather to other nearby hibernacula *45,PA11471*. The small-footed bat has been reported to hibernate in the coldest portions of the hibernacula, preferring both cave entrances and hollow caves *20,90,PA11573*. They also have been known to hibernate in cracks in the floor of caves and beneath stones on the floor *20*. The preferred sites appear to be drafty, with relatively low humidity, and temperatures near freezing *PA11488,PA11491*. Their appearance while hanging in hibernacula is quite characteristic. They hang with wings partly outstretched at a 30 degree angle from the body *45, PA11567*. Hall *PA11491* reports that clusters of these bats are never formed in hibernacula, but several individuals may be found in close proximity in the same cave. However, Mohr once observed a cluster of 3 *PA11471* and dense clusters of 50 or more have been found in Canada *20*. All observations in Pennsylvania have been solitary or clusters of 2 or 3 *PA11471, PA11441*. Individuals probably return to the same hibernacula each year *PA11471*. Migratory movements from hibernacula are largely un- known. In Ontario, Canada, two individuals banded in a cave in winter were recovered 10 and 12 miles away *20,2771*. In- divduals molt in the summer. Feeding is intiated early in the evening and completed very quickly *20*. Foraging occurs bet- ween, within, and/or below the tree canopy *4953*. Flight can be recognized among other bat species because of small size and slowness *20*. Summer habitat requirements and behavior in assumed to parallel other species of myotis. Maternity colonies may be found in cavities in the ground, beneath rocks, crevices in the walls of banks, or beneath the bark of pine trees *20,5447*. These bats are nocturnal. Population Parameters: This species may be rare in some states and common in others *20*. The longevity record is 12 years *20,89*. Aquatic/Terrestrial Associations: These bats may be found in association with m. keenii in hibernacula *109* Origin: The small-footed myotis is native to Pennsylvania *904,PA11471* The earliest verifiable Pennsylvania record dates to Charles Mohr's survey of Woodward Cave, Centre County on January 28, 1931 *PA11471*. Rhoads *2092* remarks about field encounters and specimen records in the 1800's, but no other record exists to verify the identity of these observations or specimens. Limiting Factors: Very little is known about factors limiting the distribution and abundance of small-footed myotis populations. This bat is very limited in distribution in the eastern United States and in Pennsylvania. The most serious factor would be human distur- bance of hibernacula *PA11491*. Other factors that might in- fluence small-footed myotis populations to Indiana bats, includ- ing vandalism, cave flooding, pesticide use *PA11488*. Loss of habitat is probably the primary limiting factor *20*. Hitch- cock et al. *PA11573* have suggested low female survivorship due to small populations and low reproductive rates and other factors (disease, weather, etc) are acting to limit population abundance *PA11488*. Physical description: This is the smallest myotis in the eastern U.S.. It has a tiny foot, short forearm, flat skull and keeled calcar. It has long glossy/silky brown fur, and a facial mask, ears and black membranes. The total length is 73-82 mm, with a wingspread of 212-248 mm, and a weight from 1/5 to 1/3 ounce *152,20,219,141,45*. Reproduction: Little data is available. The single young are born May-July *20,141,45*. They don't form nursury colonies but are usually found alone *8905*. Behavior: The hardiest species are found in caves/mines of eastern North America. They have a characteristic slow flight and an extension of the arms about 30 degrees from vertical when hanging. They generally roost on the ground under rocks, in crevices/occasionally in buildings and under tree bark. It has been reported hanging in the open in West Virginia, and is not as often seen as an exposed ceiling-hanger. They may not migrate far if suitable hibernation sites are nearby. The last bat to hibernate was gone by February or March. It is active in late winter and hibernates in cold, dry areas near cave entrances (drafty, low humidity, may be subfreezing). They may pack tightly and deeply. In the summer this species molts and is out in the early evening to feed among trees, and overbrush, filling its stomach quickly *147, 152,286,20,2117,141,45*. They enter hibernation in November and may be active in late January or early February, but they resume hibernation when the temperatures drop again. They feed on mosquitoes anbd small beetles and fly faster than many similar species *8905*. Origin: This species is native *134,147,152,286,20,141*. Population parameters: This species may be rare in the state. The longevity record is 12 years *20,89,ED8*. Aquatic/terrestrial associations: They may be found in association with M. keenii in hibernacula *109*.
| Life History |
| Periodicity: Active at night |
| Foraging Strategy: Gleaning |
| Foraging Strategy: Flycatching |
| Foraging Sites: Air |
| Breeding/Spawning Season: September |
| Breeding/Spawning Season: October |
| Mating System (Single breeding season): Colonial |
| Duration of Pair Bond: No pair bond formed |
| Gestation/Incubation Period: Greater than 8 months |
| Average Number of Offspring/Reproductive Effort: 1 |
| Number of Broods/Litters (Reproductive Efforts) Per Year: One |
| Nest/Den Site: Under bark |
| Nest/Den Site: Cave |
| Nest/Den Site: Under rocks/rock outcrops |
| Nest/Den Sites: Man-made structures (houses, barns, silos, etc.) |
| Nest Materials: No nest structure |
| Development of Young at Birth/Hatching: Altricial |
| Parental Care of Young: Female |
| Dispersion: Clumped |
| Periodicity: Active at dawn and/or dusk (crepuscular) |
| Periodicity: Most active in early spring |
| Periodicity: Most active in late summer |
| Periodicity: Most active in fall |
| Foraging Sites: Understory tree canopy |
| Foraging Sites: Canopy of overstory trees |
| Average Number of Offspring/Reproductive Effort: 2 |
| Nest/Den Site: Cavity in live tree |
| Nest/Den Site: Cavity in dead tree |
| Nest/Den Site: Trees |
References for Life History Codes
147, 152, 286, 20, 219, 2117, 141, 45, 134, 8905, 6037, 4953, 5447, PA7846, PA8809, PA9225, 90, PA11369, 5323, 6037, 4771, 5447, PA11573, PA11471, PA11491, PA11488, 2771, 2092, 89, 4953, PA11498, PA11441
Comments on Life History Codes