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Photo © Wisconsin DNR
Silver-haired Bat (Lasionycteris noctivagans) is a Special Concern species in Wisconsin. It is easily identified by its dark, silver-tipped fur. The silver-haired bat is insectivorous. During the summer months, silver-haired bats are found in forested habitats, particularly coniferous woodlands, adjacent to aquatic habitats like ponds, lakes and streams. In the fall this species migrates to southern states where they continue to forage and breed. Over the winter, when they are not active, the silver-haired bat can also be found in brief bouts of torpor in natural and manmade protected structures like inside trees, rock crevices, and buildings. Females store sperm until spring when they return to summer habitat where usually one pup is born in early June.
The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Silver-haired Bat (Lasionycteris noctivagans). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.
Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.
| Summary Information | |
|---|---|
| State Status | SC/N |
| Federal Status in Wisconsin | none |
| State Rank | S3 |
| Global Rank | G3G4 |
| Tracked by NHI | Y |
| WWAP | SGCN |
Identification: Silver-haired bats have dark brown or black fur which is tipped with white or light yellow on the back giving the bat its name. The ears, wings and tail membrane are black and the tail membrane is partially furred in the dorsal side. Ears are short and round with a blunt tragus. The silver-haired bat is usually easily distinguishable but may be confused with the big brown bat or the hoary bat. The big brown bat is larger than the silver-haired bat and lacks and silver or white coloring. The hoary bat is larger and has fur completely covering the tail membrane and wings, which the silver-haired bat does not have.
Similar Species: Big brown bat ( Eptesicus fuscus) Hoary bat (lasiurus cinereus)
Habitat: In fall silver-haired bats migrate south to overwinter in areas where below-freezing temperatures are unlikely. They overwinter in tree crevices and rarely in caves and mines at higher latitudes. During fall and spring migration, some silver-haired bats have been observed burrowed into ground debris or in rock crevices. In summer, silver-haired bats roost in deciduous or coniferous forest, especially near water. They roost 1-5 meters off the ground under loose bark, in crevices and abandoned woodpecker holes. Silver-haired bats may use bridges and trees as night roosts. Silver-haired bats forage in forest clearings, clear cuts and along ponds and streams.
State Distribution: Silver-haired bats are found state-wide from early April through early September, although they are more abundant in the northern part of the state.
Global Distribution: Silver-haired bats range from southern Alaska and Canada into southern United States depending on season.
Diet: Silver-haired bats feed primarily on flies and moths, but are also known to eat beetles and wasps.
Life and Natural History: Silver-haired bats mate in the fall during migration and sometimes into winter hibernation. Sperm is stored in the uterus until spring when the bats migrate back to summer habitat. Reproductive females roost alone or with a few other females starting in May. Gestation lasts 50-60 days and usually two pups are born in June. Non-reproductive female and male silver-haired bats usually roost alone in trees. Silver-haired bats begin to forage shortly after sunset, and may use temporary night roosts to rest and digest food. Silver-haired bats migrate in September and October in large numbers, sometimes with other bat species like red bats and hoary bats. Silver-haired bats live up to 12 years, and sometimes longer.
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Photo © Wisconsin DNR.
The table below lists the natural communities that are associated with Silver-haired Bat. Only natural communities for which Silver-haired Bat is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.
The table below lists the ecological landscape association scores for Silver-haired Bat. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.
Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.
* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.
Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.