Visitors to covered Red Bridgecan view colony of brown bats

[Wayne Harrison]

NATURE'S NAVIGATOR
Visitors to covered Red Bridgecan view colony of brown bats
Sunday, July 23, 2006

A visit to Red Bridge, originally known as Wertz's Bridge, at the Berks County Heritage Center near Reading, gives the nature enthusiast new respect for covered bridges.

Not only is the bridge the longest single-span, covered bridge in Pennsylvania -- 204 feet, over both the wide Tulpehocken Creek and the former Union Canal -- throughout the summer it's home to a colony of little brown bats.

Snuggled up into the rafters of the bridge's sides during the day are hundreds of female bats and their pups.

They can be spotted by anyone with a flashlight and the sense to look up when they spot a large collection of bat guano below a select area of the rafters. Visitors should steal only brief looks at the bats to avoid overly disturbing them.

The group at the bridge is a maternity colony, composed of only the females and their pups. Males in the population occupy other sites, in much smaller groups.

Each female gives birth to a single pup in June or early July. After four weeks, the young bat is fully grown and ready to leave the colony.

A full-grown little brown bat is about 2 inches long with a wingspan of about 10 inches and a weight of no more than 0.35 ounces.

They do not get tangled in anyone's hair, but each one kills and eats up to 1,200 flying insects per hour each evening from May to October. In a series of feeding flights each night, a bat needs to consume about half its weight in insects every day.

To manage such feats, the bat relies on echolocation, in which it produces a sound that echoes back to tell it what lies ahead.

Although the bats will sound off in little squeaks and chirps audible to the human ear when disturbed in their roost on the bridge, echolocation relies mostly on high-pitched sounds above the range of human hearing.

The little brown bat is the most common of the nine bat species that inhabit Pennsylvania.

The colony on the bridge, like all maternity colonies of little brown bats, is a summertime phenomenon.

Bats are hibernators, and they need a more insulated spot than the drafty bridge for the winter. In October and November, they leave their summer roosts and move to tunnels, mine shafts and caves, where they cling to the ceilings, clustered against one another, until the following April or May.

They return to the same hibernation and summer roost sites year after year.

Wertz's Bridge, built in 1867 with the Burr arch-truss design and placed on the National Register of Historic Places in 1979, is easy to find.

The Heritage Center and surrounding park are just south of the intersection of Routes 222 and 183, opposite the Reading Regional Airport. From Route 183, turn south onto Red Bridge Road, which ends in a parking lot and the paved walkway that leads downhill about 150 yards to the bridge.

MARCUS SCHNECK: 610-562-1884 or mschneck@comcast.net. Schneck's outdoor writing also appears in The Patriot-News Sports section today and Wednesday, and at http://www.pennlive.com.

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