Sandy Whidden, a professor of biology at East Stroudsburg University, and graduate student Elizabeth McGovern studied bats as they migrate through the Delaware Water Gap. McGovern has been researching bats and conservation issues as she completes her master's degree. The two visited the Lehigh Gap Nature Center recently to talk about bats.

There are two threats to bats. The first, mortality cause by wind turbines, became known 10 to 15 years ago.The second is a fungal disease, white-nose syndrome, which was introduced from Europe and creates a risk of extinction for some species.There are two types of bats the hibernating and migrating. The big brown bat is sedentary and hibernates in caves, mines or other enclosed areas that retain warmth. The little brown is a regional migratory bat, which means they do not travel far.Long-distance migrators may travel 1,000 kilometers. They do not migrate to southern South America as some birds do, but as far as the southern United States. The migrators travel in groups.Some bats like the tree bats are solitary and are difficult to study. They travel along linear landscape features such as the Appalachian range or the eastern Pennsylvania Delaware River and adjacent ridges.It is important to study bats because of wind turbines that kill hundreds of thousands each year. The question was asked why bats with their echolocation cannot avoid turbines, but Whidden said the outer ends of the blades may be traveling at more than 150 miles per hour and appear slow because they are so big.The most fatalities at the Locust Ridge Wind Farm occur from July to October.The bats that McGovern studies are the Eastern red, silver-haired and hoary bats. She has three ridge sets and three river sets using acoustic monitoring. They record echolocation. The Eastern red has the most activity on the ridges. She said some may migrate along the Atlantic coast.The hoary bat showed higher activity along the river. Both the ridge and river are used early by the silver-haired bats but move up to the ridge later in the season. Linear features are important to them.Acoustic monitors run for seven hours. There is no electronic reporting system. McGovern visits each monitor three times a week.Someone wanted to know how to attract bats to a yard since they help keep down the insect population.Whidden said it is hard to do since the white-nose syndrome came. There are bat boxes that can be placed. Whidden said he can provide requirements on how to make a bat house and how it has to be situated.McGovern said the best way to tell if bats are just flying around or migrating is to understand when the migration season is in an area. She was asked her motivation for the study and said she has been inspired by the bats.Whidden said they want to learn the ecology of the bats and how they might contribute to conservation. He said their high-frequency sounds are attenuated so quickly that they cannot be followed and the sounds do not keep them safe from turbines.He said possibly the turbines could be slowed or turned off at nighttime until the wind begins to pick up again toward dawn.Migration is at the same time as mating season, so they might misunderstand what turbines are, said McGovern.For the bats that stay at home in caves and mines it is fairly easy to get a reasonable estimate of numbers. The hoary bat has a lower and flatter call, and with experience it can be differentiated from other bats.Dan Kunkle asked why a migration chart has two big peaks and nothing in between. McGovern said they do flock together and weather can be a factor.Bats have been banded, but Whidden said they move so far and so fast that they are hard to track.White-nose syndrome only affects bats when the body temperature drops below 40 degrees, which means migrating bats are not affected as severely. Among the cave dwellers the big brown is not affected as much with only 50 percent fatality, and that may be that with a bigger body it maintains temperature better. The little brown has a fatality rate of 97 percent."There is so much we do not know," Whidden said.