Species

Silver-haired bat

Lasionycteris noctivagans

A black bat frosted with silver, a slow and graceful flier that winters in the South.

Photo Sam Kieschnick (opens in a new tab) / iNaturalist, CC BY 4.0 (opens in a new tab)

At a glance

Size: Body about 9 to 11 cm; wingspan about 27 to 31 cm
Weight: About 8 to 12 g
Habitat: Forests, especially near water, and wooded neighbourhoods
Diet: Moths, flies, midges, caddisflies, beetles and other soft-bodied insects
Active: Night, emerging later than most bats
Roost: Behind loose bark, in tree cracks and cavities, and sometimes in woodpiles and buildings
Young: Usually two pups
Rabies vector: Yes

Identification

Key marks: Black to dark brown fur with silver-white tips on the back, giving a frosted look; short, rounded, bare black ears
Tail membrane: Furred only on its upper surface near the body
Told apart from: Hoary bat, which is larger, brown and yellow-throated
Told apart from: Big brown bat, which is plain brown without silver tips
Where to look: Winter roosts in woodpiles, under bark and in outbuildings in the South; foraging over ponds and streams

Behaviour

Silver-haired bats are slow, agile fliers that hunt low over water, along forest trails and in clearings. They usually emerge late in the evening, which is where their scientific name, "night-wandering", comes from.

They are migrants. Many spend the summer in northern forests and move south for the winter, and in Georgia they are mainly winter residents, sheltering behind bark, in tree hollows, rock crevices, woodpiles and sheds, and waking on mild nights to feed.

Why they matter

Silver-haired bats feed heavily on the small, soft insects that rise from ponds and streams — midges, caddisflies and mayflies — and on moths, linking the insect life of the water to the forest around it.

They also show how much wildlife depends on dead wood. Loose bark, hollow trees and old woodpiles are their bedrooms, and a tidy woodland with every dead tree removed has nowhere for them to sleep.

Reproduction and lifecycle

Mating — autumn; fertilisation is delayed until spring
Gestation — about 50 to 60 days after fertilisation
Birth — June and early July, usually two pups
Flight — at about three to four weeks old
Independence — by late summer
Lifespan — up to about 12 years has been recorded; much less is usual

Living around people

Check stacked firewood before moving it in winter; silver-haired bats sometimes sleep between the logs.
Leaving standing dead trees where they are safe gives roosts.
Never handle a bat with bare hands; a variant of rabies associated with silver-haired and tricolored bats has been involved in a notable share of the rare human rabies cases in the United States.
A bat found in a woodpile or shed in winter is usually just asleep; leave it where it is.

Misconceptions

A bat sleeping in a woodpile is sick. In winter this is normal for silver-haired bats.
Only a bite you can feel matters. Bat teeth are tiny; anyone who wakes to find a bat in the room, or who has handled one, should speak to a doctor.
Bats that live in the north stay there all winter. Many silver-haired bats fly hundreds of kilometres south.

Related species

Seasonal activity

When this species is breeding, and when there are nests on the ground. Mowing during the shaded months is how most nests are found.

Breeding and active nests by month for this species
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Breeding	Jan: no	Feb: no	Mar: no	Apr: no	May: no	Jun: no	Jul: no	Aug: no	Sep: no	Oct: no	Nov: no	Dec: no
Active nests	Jan: no	Feb: no	Mar: no	Apr: no	May: no	Jun: no	Jul: no	Aug: no	Sep: no	Oct: no	Nov: no	Dec: no
Notes	Wintering bats roost in the South; torpid in cold weather	Active on warm nights	Northward migration begins	Most leave the Southeast for northern summer ranges	Females gather in small maternity colonies in tree cavities in the north	Pups are born, usually two	Young begin to fly at about three to four weeks old	Young are independent	Southward migration begins	Migrants arrive in the Southeast	Wintering bats settle into bark crevices, woodpiles and outbuildings	Mostly torpid; active on mild evenings

Where it lives

Recorded in 58 states and provinces. Each one links to the other animals there, and to the rehabilitators licensed for them.

Treated as a rabies-vector species in Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming, Alberta, British Columbia, Manitoba, New Brunswick, Nova Scotia, Ontario, Quebec and Saskatchewan. There, only a certified rehabilitator may take one.

Canada

If you found one

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