Tailing Elusive Wood Rat

November 21, 1993|By Greg Tasker | Greg Tasker,STAFF GRAPHICStaff Writer

SWANTON -- Dan Feller climbs rocky outcrops and ducks into hollows each week along a rugged, forested ridge on Maryland's highest mountain. He tracks a small, furry creature that by name would cause most city dwellers to scream with contempt.

His subject is the Allegheny wood rat, a native rodent sometimes called the pack rat that is declining mysteriously in Maryland and other parts of the Eastern United States.

The elusive, nocturnal mammals are only distantly related to the notorious, sinister-looking Norway and black rats that accompanied colonists' ships to America and have been pests ever since.

Wood rats adapted long ago to rugged habitats largely unused by humans. They eat nuts and seeds in the forest and are hunted by barn owls, coyotes and bobcats.

"These Allegheny wood rats are really cool," said Ed Thompson, a regional ecologist for Maryland's Natural Heritage Program. "People think squirrels are cute. Wood rats are as cute or as endearing as any squirrel."

They're docile -- even playful -- around humans, he said. Unlike chipmunks and other small mammals, the wood rats remain calm when trapped. Wood rats are known for packing in their nests shiny items such as buttons, bottle caps and even an occasional coin. Their nests sometimes yield "stolen" clues about how people lived many years ago.

Mr. Feller's job is to determine why the state's wood rats, believed to number fewer than 200, are disappearing. He has put radio collars on eight rats -- transplanted from West Virginia and other sites in Maryland -- to track their movements along the Backbone Mountain ridge in Garrett County, where a previous colony perished.

"The point of the study is to recover a dead animal and do a necropsy [an animal autopsy] and determine the cause of death," said Mr. Feller, an environmental specialist hired by the state's Natural Heritage Program to conduct the study.

Based on work in New York, researchers believe a raccoon parasite is a culprit in the wood rat's decline. Wood rats are believed to ingest inadvertently eggs of deadly roundworms while feeding on undigested seeds in raccoon droppings.

"If people like [Mr. Feller] come up with similar results in other states," said Alan Hicks, a senior wildlife biologist with New York's Department of Environmental Conservation, "it'll be pretty convincing the parasite is the major cause."

Mr. Thompson cautioned that "we don't know anything for sure yet," pointing out that factors other than Western Maryland's plentiful raccoons may be in play as well.

For example, altered diets may be relevant in Western Maryland, where extensive gypsy-moth infestations have caused the decline of many acorn-bearing oak trees in recent years. The American chestnut, another food source, also has disappeared from Maryland forests.

Allegheny wood rats -- recently designated a subspecies of the Eastern wood rat -- are comparable in size to squirrels and have furry tails and big eyes.

They once were found at about 100 sites in Garrett, Allegany, Washington, Frederick and Montgomery counties. Now, they exist at about 30 sites from eastern Garrett to western Frederick County.

"We're very concerned," said Judy Jacobs, an endangered species biologist with the U.S. Fish and Wildlife Service in Annapolis. "There's been a horrendous decline in the northern part of their range."

The rats can be found along the Appalachians from the Tennessee River to New York. They also live along river valleys in Ohio and Indiana. But the species has been extirpated in New York, Connecticut and most of Eastern Pennsylvania.

Although concerned to the point of putting up $40,000 over three years to study their decline, the federal government has not listed wood rats as an endangered species because they are believed to be sufficiently abundant in some areas. West Virginia, Virginia and Kentucky have healthy populations.

Mr. Feller began his work three years ago by trying to find out how many wood rats existed in Maryland and where.

On average, he found that four wood rats live in one nest. Populations have ranged from one to 20 at other sites. They generally live in cliffs, caves or rocky outcrops.

Mr. Feller baits traps with peanut butter, weighs trapped animals, checks their reproductive condition and looks for signs of infection, such as loss of coordination.

Though biologists say some people question the state and federal governments spending money on a species of little public concern, researchers like Mr. Feller and Mr. Hicks believe wood rats are worth saving.

"I don't personally value species on how they're doing in the Nielsen ratings," Mr. Hicks said.

"I believe we have to maintain what we have on this planet for future generations -- whether that's grizzly bears or wood rats. Future generations will look kindly on us for saving them."

ALLEGHENY WOOD RAT

The only rat native to the Eastern United States, it once ranged the Appalachian Mountains from New York to the Tennessee River.

In Maryland, these rats live in the mountains of Frederick, Washington, Allegany and Garrett counties, but are declining in numbers.

SIZE: Adults weigh about one pound and, including tail, are as long as 18 inches.

COLOR: Tri-color coat, white underneath, chestnut on the flanks and dark brown on top.

L HABITAT: Caves, rocky or boulder fields, crevices in cliffs.

DIET: Variety of vegetation, fruits and nuts.

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