ANNAPOLIS – While an army of Draculas and other assorted ghouls invade neighborhoods this Halloween Friday, an equally impressive force of the vampire’s bat-brethren will take over bridges, caves and forests across Maryland en route to Latin America and other winter roosts.
Fall probably brings the greatest population of bats to Maryland, said Dana Limpert, a biodiversity analyst at Maryland’s Department of Natural Resources. But the night-flying mammals are “very difficult to track,” she said.
In fact, no one knows exactly where and how many bats migrate. Solving the mystery of bat migration, scientists say, will be a key step to preserving endangered bat species, like the Indiana bat seen in Maryland.
Bats are nocturnal flying mammals more closely related to humans than rodents. But unlike the Transylvanian count, bats that inhabit North America eat insects instead of blood, and many scientists contend they provide more benefit than threat to humankind.
Preserving them is in humans’ best interest. They gobble pests that irk humans and destroy crops, Limpert said, and they are uninterested in man.
But bat populations are threatened by development, pesticides and commercialization of caves.
The state’s trick-or-treaters won’t be imperiled by blood-drinking species – Maryland has none – but there are three worldwide – all residing in Latin America. These vampire bats actually lap up blood like a cat with a saucer of milk after biting an animal with their two front teeth.
Bats in Maryland are far more interested in finding a place to hang upside-down.
This autumn search for lodging leads locally-migrating bats to caves, abandoned mines or, in the case of the big brown bat native to Maryland, warm attics to winter in.
Others, like the hoary bat that ranges from Canada to Latin America, can drop in for resting and refueling before moving on.
Yet their travel routes remain unclear.
“We know very little about the movement of these things,” said Don Wilson, a senior scientist at the Smithsonian National Museum of Natural History, “particularly long-distance migration.”
Bats are exceedingly hard to track because they are secretive creatures, often hard to find more than once. Radio trackers tiny enough to fit between a small bat’s shoulder blades have only enough battery life to track them for one or two weeks.
Those problems have led scientists to try genetics to aid tracking.
Maarten Vonhof, a post-doctoral researcher at the University of Tennessee is now collecting genetic samples from bat populations nationwide, and hopes to secure funding for a study that uses these samples to establish migration patterns.
If he finds a bat in Maryland that matches the genetic signature of a bat population in Canada “at least I’ll know that bat spent the summer in Canada.” – 30 – CNS-10-29-03