Slogging in Maryland to snare, catalog bats

Unknown: Gloved researchers wade in streams and mud to learn how far bats travel, and which ones live here.

July 26, 2004|By Jason Song | Jason Song,SUN STAFF

CATOCTIN MOUNTAIN PARK - Being a bat-catcher is a messy business.

Your jeans get wet from wading in streams or mud to set up nets. You spend so much time in the woods you can tell the difference between a bat's squeak and a flying squirrel's chirp. On a good night, you spend most of your night pulling squirming, biting animals from the trap. On bad nights, all you do is slap mosquitos and watch the bats flit around the nets.

"We only catch the dumb ones," jokes Rachel Gauza, one of the researchers on the University of Maryland Center for Environmental Science team.

But for Gauza and her fellow researchers, the effort is worth it. They are surveying bats in the state as part of an effort by the federal government to count the number of species in the nation's preserves. What they find could help answer fundamental questions about the animals - how far some bats migrate, where they hibernate and how many live in Maryland.

They also hope to find an Indiana bat, an endangered species that hasn't been seen in Maryland since the late 1980s. Scientists say that all the conditions are ripe for the bat's comeback, which could lead to extra funds for the park from the federal government to help protect the animal.

"It would be a huge thing for the park," says James W. Voight, resource manager for the Frederick County park.

On a recent night, there was little time for slapping mosquitos or searching for salamanders, the bat-catchers' other favorite diversion. The group's AnaBat II, a machine that detects bats' high-pitched squeaks, chirps continuously, and the researchers are constantly wading in the stream to pick the bats out of the nets, hung over a mountain stream where insects gather.

In the first hour, the group collected nine animals, not counting one that was snared but managed to claw its way free. Bats occasionally rip apart the nets to escape.

"Some of the big ones, it looks like they're eating the net," says Jennifer Karow, a senior at Muskingum College in New Concord, Ohio, who is working on the project this summer.

The furry mammals hiss and bite when they are pulled from the net.

"If you blow on their faces, sometimes it helps," Karow says before puffing on the bat, which doesn't stop angrily squealing.

Karow measured the animal's wings, slipped it into a plastic bag and weighed it, then held its wings out while Gauza took small skin samples. Researchers say the bats don't feel pain and that the skin grows back in about three weeks.

The bat is released and the skin samples shipped to a Princeton University researcher for analysis.

Federal grant

The project is paid for by a $120,000 National Park Service grant, which the Maryland group received two years ago. The group, which will be working for several more weeks, conducted a similar project last summer. They will forward their results to the federal government at the end of the summer.

Most of the captured animals are little brown bats, or Myotis lucifugus, which are about the size of an egg yolk. When they screech and hiss, their black eyes narrow to the size of pinheads, and when a bat bites a volunteer's gloved finger, it resembles a terrier attacking a telephone pole.

`Beat you up'

Most Maryland bats are small, weighing about an ounce at most. The Eastern red bat, Lasiurus borealis, is one of the biggest bats in the state, but when Gauza pulled one out of the nets, its body easily fit in her palm even as it flapped its black wings furiously.

"They like to try and beat you up," she says.

The researchers' work could have national implications. Maarten Vonhof, a graduate student at Princeton, is analyzing bat skin and hair samples collected by nearly 60 researchers around the country.

The tissue will reflect the animal's environment - a bat living in Florida will have a different chemical makeup than a bat from Maryland - and should help determine how far they have migrated.

Many believe that bats will migrate only relatively short distances, but some species have been found as many as 200 miles off shore, Vonhof says. Dead bats have also been found near wind turbines, suggesting that they conserve energy for long distances by riding the wind much as birds do, he adds.

"There's a lot we don't know," he says.

One of the greatest unknowns is the prevalence of the Indiana bat, Myotis sodalis. There were once small numbers of the animal in Maryland but the bat has not been sighted in nearly 20 years. Nobody is sure why the bats apparently left, although some speculate that the bats, which hibernate in caves, ran out of habitat.

Hope for comeback

State officials hope the bat may make a comeback in protected areas like Catoctin Mountain Park. Over the past decade, black bears and coyotes have returned to the park, Voight noted.

Researchers say they don't get their hopes up, saying they've never even netted anything that resembles an Indiana bat, which is bigger than most Maryland species and has an upturned nose.

But they admit that they can't help but get excited when they see something squirming in the net.

"You always got to check just in case," Karow says.

Bats wanted

University of Maryland Center for Environmental Science researchers are capturing bats to survey what species live here. Species among the bats caight include:

Little brown bats -- Myotis lucifugus

Eastern red bat -- Lasiurus borealis

Big brown bat -- Eptesicus fuscus.

Bat facts

The little brown bat feeds on soft-bodied insects such as moths, flies, midges, mosquitoes and mayflies. A lactating little brown bat can eat as many as 4,500 insects a night.

The larger big brown bat preys mostly upon beetles such as ground beetles, June bugs and cucumber beetles. A colony of 150 big brown bats can eat well over 120,000 agricultural pests a night.

Bats are long-lived animals. Some have been known to live more than 30 years.

Source: Department of Natural Resources

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