But like most neighbors, they also need our help
By Gaynor Bigelbach
AYER OR ANYWHERE — If the only bats hanging out in your backyard are Halloween decorations, then you are missing out on some of nature’s most fascinating, most beneficial, yet most misunderstood creatures.
New England is home to six bat species, the eastern pipistrelle, hoary bat, northern long-eared, the small footed, and both the little brown and big brown, all of whom are insectivores. They feed predominantly on midges and mosquitoes, which is good news to anyone, like myself, who spends a lot of time outdoors.
Bats feed on the wing, emerging at dusk. A single bat can consume an astonishing 1,200 mosquitoes per night.
Bats are superb, if diminutive, predators because of their perfectly evolved hunting skills. Most people are aware that bats use a technique called echolocation to find and intercept their prey. As they fly, they emit a series of high frequency squeaks, and their supersensitive ears can detect when the sound waves bounce back off an object. This process might sound pretty routine in these high-tech days, but those sound pulses, or squeaks to our ears, are sent out at about twenty pulses per second when the bat begins hunting, and ratchet up to an amazing 500 pulses per second as it homes in on an insect. In fact, biologists have discovered that echolocation is so phttp://www.about-bats.com/graphics/bat-fruit-2.jpgrecise that a bat can detect an object as minute as a single human hair. So, perhaps we can finally lay to rest the myth that bats can get tangled up in our hair and bite us in their panic to escape. Bats sometimes swoop around us because we act as lures to mosquitoes and midges, and not because they are aggressive.
At this time of year in central Massachusetts bats are getting ready to hibernate. After raising their young throughout the summer months, they have spent late summer and early fall laying down stores of fat. In the case of the little brown bat, they are returning to colonies in caves and disused mines, known as hibernacula. The Big browns are opportunists, seeking out nooks and crannies and often hibernating in buildings, like barns and silos.
Bats mate in the fall but, remarkably, fertilization does not occur until the females wake from hibernation in spring. Bats are amongst the slowest reproducing animals on the planet and have only one live young per year. They are devoted parents tending this baby with enormous care. Now these amazing creatures are under threat throughout the Northeast.
In recent winters, entire colonies of hibernating bats have been discovered dead, or dying, from a devastating disease now known as White Nose Syndrome. The condition has a 97 percent mortality rate, so when mated females are killed, the next generation is also destroyed, which is disastrous for such a slow breeding species. Field biologists are scrambling to understand what is causing the condition and why its victims are so helpless against it. In what may be a significant breakthrough, biologist David Blehert has identified a new strain of cold loving fungus called geomyces destructans growing on the bodies of afflicted bats.
At time of writing it is too early to say whether it is the fungus that is responsible for the bats’ deaths or whether it is simply an opportunistic fungus attacking already compromised animals. It appears that the handful of survivors were able to burn off the fungus as their body temperature returned to normal but we do not yet know whether the illness will return when they go into hibernation again this year.
It is essential that the bats that survive this winter are able to birth and raise their young in safe maternity colonies next summer. One of the best ways we can help them is by installing bat boxes during the winter months in readiness for the bats when they emerge. Installing a bat box in your yard will not lure bats to take up residence in your home. If there was a way for bats to get inside, they would already have found it. As it is with real estate, so it is with bat boxes — no matter how perfect the home, it is all about location. The ideal location for a bat house is within a quarter mile of a water supply and 10 to 30 yards free of cover so that they can exit without encountering predators. The box needs to be situated where it will get a minimum of seven hours of sun a day, and must be at least 10 feet off the ground. Please do not place a bat box where it may be vandalized.
There are several bat boxes available commercially, or you can build your own using the templates from books such as The Bat Builder’s Handbook by Merlin S. Tuttle. There are also a number of free plans available on the Internet at sites like www.batconservation.org and www.batroost.com. which are relatively inexpensive to make. The “rocket box”, developed by wildlife biologists Dan Dourson and John MacGregor, is one of the most successful bat boxes with a very high residency rate. The rocket box emulates a tree with exfoliating bark which is one of the most common roost sites.
As part of a broad-based plan to combat WNS, MassWildlife is asking the public to report any unusual behavior, such as bats seen flying during the winter months, and appearing during daylight hours, both of which are symptoms of bats afflicted with WNS. The fungus cannot live in temperatures above 40 degrees Fahrenheit, and cannot infect humans, however, anyone finding a sick or dead bat should not handle it but should inform MassWildlife immediately.
We have become so attuned to hearing that particular species of plants and animals are under threat that the warnings glide over us. We are fast closing in on the point where we will no longer be able to ignore them. In June, during testimony before Congress, experts predicted that if the die-off caused by White Nose Syndrome continues unabated, we will be facing the most serious threat to wildlife in a century.