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For information on Wisconsin's rare vertebrate animals, contact:
Rich Staffen
Conservation Biologist
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Jay Watson
Conservation Biologist

Hoary Bat (Lasiurus cinereus)



Hoary Bat (Lasiurus cinereus) has fur that varies from grey to chocolate-brown and is tipped with white, giving the bat a frosted appearance. This species is insectivorous and typically roosts in coniferous and mixed hardwood-conifer forests, but has also been found in trees along urban streets and city parks. In fall, the hoary bat migrates to southern states to spend the winter. Mating occurs during fall migration, and females store sperm until they return to summer habitat in spring. One to four pups are born in early June. This species is not actively tracked in the Natural Heritage Inventory Database, but it could be tracked in the future if there is further evidence of its decline.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Hoary Bat (Lasiurus cinereus). 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.

Lasiurus cinereus is not tracked by the Wisconsin Natural Heritage Inventory Program at this time (this species is not on the NHI Working List).
Summary Information
State Statusnone
Federal Status in Wisconsinnone
State RankS3
Global RankG3G4
Tracked by NHIW

Species guidance

Identification: The hoary bat is Wisconsin's largest bat. Their fur is dark and usually tipped with white. The overall appearance of the hoary bat is dark brown to yellow with a white or cream underbelly and fur covering the tail membrane and the ventral side of wings. The ears of the hoary bat are large, round and framed in black. The silver-haired bat may, at first glance, be confused with the hoary bat because of the coloring, but the silver-haired bat is much smaller and lacks the same amount of hair on the tail membrane and wings.

Similar Species: Silver-haired bat (Lasionycteris noctivagans)

Habitat: In September and October, the hoary bat migrates south to Arizona, California and Mexico and Central America to overwinter. In April and May, hoary bats migrate back to Wisconsin to summer habitat. Hoary bats roost alone and rarely, if ever, form maternity colonies. They roost readily in both hardwood and coniferous forests and prefer large, mature trees. They roost 10-15 feet above the ground on branches among foliage oriented to the south for warmth. Because of its coloring, they can often be mistaken for pinecones at first glance. Hoary bats are larger and less maneuverable than other bats, and tend to forage in open areas or at high elevations.

State Distribution: Hoary bats are found throughout the state in favorable habitats from May through September, though they appear to be more common in the northern part of the state. Hoary bats are not a common species in the state.

Global Distribution: Hoary bats are one of the most pervasive bat species in North America found from southern Canada down into South America, and limited numbers have been recorded in Bermuda, Iceland and the Florida Keys. It is also one of only two native mammals found on the Hawaiian Islands.

Diet: Hoary bats will sometimes establish feeding territories and will actively chase other bats away. Their diet consists heavily of moths, but they are also known to eat beetles, flies and true bugs and sometimes even other bats, although those occurrences are rare.

Life and Natural History: Hoary bats migrate in September and October to wintering grounds, and return in April and May to Wisconsin. They breed in the fall during migration, and sperm is stored over winter in the uterus of the female until she migrates back in the spring. The female gives birth to usually two pups in late May or June, although up to four pups per female have been recorded. The young are able to fly by themselves about one month after birth. The hoary bat is a reclusive bat by nature preferring to be alone most of its life except during mating and in the fall when they may migrate in groups. Little to no information exists on habitat and foraging activity of the hoary bat, and more research is needed on the life history of this bat.

Other resources

Links to additional Hoary Bat information

Other links related to mammals



Hoary Bat

Photo © Paul Cryan.

Hoary Bat

Hoary Bat

Photo © Heather Kaarakka.

Last revised: Thursday, December 22, 2022