Monday, April 11, 2016

Bats Battle for Survival

The United States has 45 native bat species across the nation. Virginia with its mid-Atlantic location has bat species found in both the Northeast and Southeast. Though 17species of bats have been sighted in Virginia, only 15 are usually found in the state. Bats are the number one predator of night-flying insects, and all bat species in Virginia are insect eaters. On summer nights I can sit on my deck and watch the small local bats coming from their summer roost in the woods behind my house nab insects out of the air.

However, the bat population is being endangered by white-nose syndrome, a disease affecting hibernating bats. Named for the white fungus that appears on the muzzle and wings of hibernating bats, white-nose syndrome or WNS is causing extensive die-outs of bats in eastern North America and has now spread to the west. First documented in New York in the winter of 2006-2007, WNS has spread quickly among bats in other affected areas, killing more than six million beneficial insect-eating bats in North America since it was first documented nearly a decade ago. In the United States WNS has been detected as far south as Mississippi and now has reached Washington State. The presence of WNS in Washington was verified by the U.S. Geological Survey’s National Wildlife Health Center last month.
from USGS  Fish and Wildlife

According to Bat Conservation International those 6 million lost bats would have consumed over 4,000,000 tons of insects each year. Bats that benefit humans by consuming large quantities of insects that can carry disease and impact forest health and commercial crops. Without the bat populations we would be buried in insects, so we need to care what is happening to the bat populations. Scientists describe WNS as the most serious known decline in North American wildlife.

White-Nose Syndrome is caused by a white fungus that thrives in the cold environments where bats hibernate. This fungus was formerly known as Geomyces destructans is now known as Pseudogymnoascus destructans. Hibernating bats with white-nose syndrome often display this white fungus on their noses and on other hairless parts of their bodies including their wings. In Virginia bats hibernate in the caves of the karst terrain, often hundreds of miles from their summer roosts.

The WNS fungus isn't always visible to the naked eye and usually is not seen on bats found flying or dead outside of their hibernacula or at their summer roosts. Bats with WNS act strangely during the cold, winter months, including flying outside in the day and clustering near the entrances of the caves and mines where the bats hibernate. Bats have been found sick and dying in unprecedented numbers in and around caves and mines. In some hibernacula, 90 % to 100 % of the bats have died. The bat populations in the United States are being devastated by white-nose syndrome; however, WNS is not known to pose a threat to humans, pets, livestock or other wildlife.

It is believed that white-nose syndrome is being spread from bat to bat, but it is also believed that humans have had a hand in the spread of the fungus. You can help by avoiding possible spread of WNS by humans. Stay out of caves and mines where bats are known - or suspected - to hibernate. Stay out of all hibernation sites when bats are hibernating (winter).

"We are extremely concerned about the confirmation of WNS in Washington state, about 1,300 miles from the previous westernmost detection of the fungus that causes the disease,” said U.S. Fish and Wildlife Service Director Dan Ashe. “Bats are a crucial part of our ecology and provide essential pest control for our farmers, foresters and city residents, so it is important that we stay focused on stopping the spread of this fungus. People can help by following decontamination guidance to reduce the risk of accidentally transporting the fungus.”

There are a small number of bats that exhibit a resistance to the fungus. Preserve the bats that survive the winter hibernation and return to roosts near your home. Reduce disturbance to natural bat habitats around your home (e.g., reduce outdoor lighting, minimize tree clearing, and protect streams and wetlands). This is actually a good idea for maintaining a healthy environment. Please take care of the bats that survive. If bats are in your home and you don't want them there, work with the Department of Natural Resources to exclude or remove them without hurting them after the end of the summer when they have moved to their hibernation location. The best time to exclude bats is when they aren’t in your home.

The soundest long-term solution for the management of bats that enter buildings and cause a nuisance problem or a potential public health hazard is by bat proofing the structure. Excluding bats from buildings requires establishing one-way exits through which the bats can leave but cannot return, while also sealing all other potential entry points. This process of eviction and exclusion is the only effective and permanent solution when bats in a building are unwanted. Bats may roost in attics, soffits, louvers, chimneys and porches; under siding, eaves, roof tiles or shingles; and behind shutters. Click this link for guidelines in excluding bats from your home.

Another way you can help is to report unusual bat behavior including; bats flying during the day when they should be hibernating (December through March) and bats roosting in sunlight on the outside of structures. More difficult to tell is unusual behavior when bats are not hibernating (April through September); however, bats roosting in the sunlight or flying in the middle of the day is unusual. Bats unable to fly or struggling to get off the ground is also unusual. In Virginia report observations to the Department of Natural Resources.

You can also watch the Fish and Wildlife Service video Battle For Bats: Surviving White Nose Syndrome
from Fish and Wildlife Service Video

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