Whidden, a professor of Mammalogy Systematics and Conservation Biology at East Stroudsburg University, detailed an ongoing study of bat species and populations in the Upper Delaware before the Upper Delaware Council (UDC) on November 6.

Prefacing local work, Whidden cited a 2011 Science Magazine article that provides a number of illuminating statistics on the national problem, as well as the economic impact caused by of a disruption of one link in an ecosystem: One colony of 150 big brown bats in Indiana consume 1.3 million pest insects annually; the loss of bats as an insect predator would cost North American agriculture $3.7 billion annually, up to $53 billion if pesticides are required as alternatives. And the latter figure does not include downstream environmental impacts from increased pesticide use.

Bat numbers are in decline due to disease and technology, such as wind turbines.

White nose syndrome is a fungus disease, believed to have been imported from Europe on the gear of cave explorers. Introduced at New York’s Howe Caverns in 2005-06, it has been ravaging hibernating bat colonies in Northeastern caves and has spread south and to the central states. From bat census numbers before and after the disease’s introduction, scientists have found various species have decreased from 12% to 91%.

Technology, in the form of wind turbines, has also taken a high toll on migratory bats. Whidden said that the sonar-type guidance that bats use in flying apparently does not detect the action of turbine fans. There are no known numbers, but he characterized the impact as a “massive mortality” annually.

According to the Science Magazine article, “by 2020 an estimated 33,000 to 111,000 bats will be killed annually by wind turbines in the Mid-Atlantic Highlands alone.”

Adding to the concern, bats normally are long-lived and have a low reproduction rate, producing only one or two young annually.

Local studies

Using stationary and mobile acoustic monitoring of their movements, Whidden has been studying native and migratory bat populations on the PA side of the upper and middle Delaware River since 2007. Study participant Larry Laubach said this year’s studies between Shohola and Stockport included 10 to 12 nights in June and July.

Laubach said some species showed losses reflecting national statistics. The big brown bat, historically one of the most abundant, has been affected locally.

However, the little brown bat, which has been depleted in the Middle Delaware, still has a relatively wide distribution in the Upper Delaware. Estimated numbers in colonies at Lackawaxen, Ten Mile River and Cochecton Station have increased from 300 to 650 this year, he said.

Cochecton UDC delegate Larry Richardson noted that the bats are “not tidy tenants.”

There is no cure for white nose fungus and efforts to make wind turbines more bat-friendly have failed.

Westfall delegate Chuck Pranski asked about the possibility of introducing European bats, which have developed immunity to the white nose fungus. Whidden said that as far as he knew such an option had not been considered.

There are other measures available to assist bat populations. Whidden said artificial roosting units, “bat boxes,” are being used. Two of these have been mounted near the Zane Grey Museum in Lackawaxen.

A Penn State study found bats will use boxes mounted in areas receiving at least seven hours of sunlight daily, when traditional roosts in buildings are sealed.

Laubach noted that bats will still seek building roosts. They should be removed carefully—fishing landing nets are often used—while avoiding direct contact, as rabies infection is a continuing concern.