(Note: White-nose Syndrome, caused by the fungus Geomyces destructan, has been associated with the deaths of over one million cave-dwelling bats in the U.S. since 2006. The fungus has infected six species of insect-eating bats in the northeastern and southern U.S. causing the deaths of 75% to over 90% of some surveyed populations ( http://www.fws.gov/northeast/white_nose.html ; http://www.fort.usgs.gov/wns/ ). It has not yet reached Iowa's bat populations as far as biologists know. During a search for the fungus in Europe, researchers have discovered the first bat similarly infected in France. For the complete paper, and implications of this finding, see ( http://www.cdc.gov/eid/content/16/2/290.htm .)

Introduction:

Over the winter, Marlene Ehresman, IWC Executive Director, and her husband, Bruce Ehresman, Iowa DNR Wildlife Diversity Biologist, received 22 bats from individuals, animal control or students at Iowa State University's Wildlife Care Clinic. All of the bats, except one, were Big Brown Bats, a common winter resident of attics, buildings and hollow trees. One bat was a Silver-haired Bat -- the first of this species the Ehresmans have cared received as Silver-haireds are typically migratory bats. It seems fitting that it be the Iowa Wildlife Center's Creature Feature.

Natural History of the 

Silver-haired Bat

Lasionycteris noctivagans

"Hairy Bat Night Wanderer"

By Rose Danaher

Hairy bat night wanderer.  It may sound like something out of a horror movie, but this creature is actually one of the most beautiful and mysterious bat species in Iowa. The silver-haired bat, whose scientific name, Lasionycteris noctivagans, translates to "hairy bat night wanderer", is a woodland species that can be found in Iowa from early April through early October. While the species will roost in younger woodlands, its chosen roost is in old growth forest, which is one reason it is rarely encountered by humans.

The silver-haired bat is a medium sized bat that has blackish fur with distinct silvery tips. This unique coloring gives the bat an icy or frosted appearance. They spend the majority of their lives in woodlands and often roost alone beneath loose bark and in high, large diameter snags. Although they are a migratory species, typically moving south several hundred miles where there are more abundant insects in winter months, there are records of single silver-haired bats that have turned up at wildlife rehabilitation clinics as late as January.

Because of the silver-haired bat's dependence on old growth forest, rotten snags and abandoned woodpecker holes, it is important for land managers to consider the bats' needs when doing restoration work. At WildWay, we carefully analyze the effects of each step we take during the restoration process.  We generally leave dead trees and snags as habitat not only for the silver-haired bat, but the many other species that frequent Wildway's woodlands.

Rehabilitation Notes for the Silver-haired Bat

By Marlene Ehresman and Sarah Hart

Success. During a warm spell in late April, we released the Silver-haired Bat in the upland of an urban creek, not far from where it was found. We released it after giving it time in a screen shelter to test its wings. But what did we have to consider as we cared for him these past months?

Winter. There are no babies to care for; only juveniles and adults who have found themselves too close to humans for comfort - either for the bats or the people. This year seemed to be unique as one rehabilitator in the Chicago area had more Silver-haired Bats presented to her facility than the typical Big Brown Bat. But how do we care for these warmth-seeking furry friends?

Overwintering bats may sound relatively simple, requiring the typical food, water and shelter any species needs to survive. Proper humidity and temperature, quiet space to house them, rabies pre-exposure vaccination for any caregiver and time allowance for cleaning and feeding are other important aspects to consider. Doing it right is not as simple as you might think. If you are curious about how rehabilitators might over-winter bats, or are a rehabilitator who needs a few ideas, please follow this link. Please understand that these notes are meant to offer perspective on caring for bats and does not contain all the information necessary to successfully over-winter them.