Halloween festivities are only a few weeks away, with their mock-scary themes of ghosts, goblins and bats. By then, many of the region's real bats will have left town, headed for winter hibernation caves.

October is a month of transition for these creatures, the only mammals that truly fly. Thousands of little browns and eastern pipistrelle are winging their way to caves in western Virginia and Maryland, where they will hang out upside down with their buddies and live life in the slow lane. During hibernation, their oxygen consumption drops to 1 percent of its normal level.

Other bat species migrate here for the winter from farther north. And for some species, such as big browns, it is mating season, although the babies will not be born until next year. These are the bats that often nest in attics. At this time of year, they leave their "maternity colonies" in warm buildings for cooler winter digs, such as garages.

The region's 10 bat species are all insect-eaters, so there's no need to fret about vampires. The big brown bat chows down on beetles, the red bat goes after moths, and smaller bats get whatever is flying around in their vicinity. They catch insects in their mouths, then spread their membrane-enhanced legs out and forward to form a curtain that encloses their prey. They forage during the evenings, although they do not go out as much when the temperature drops below 60.

They do good work, but they do not get much thanks for it.

Leslie Sturges would like to change that. She is director of Bat World of Northern Virginia, part of a national nonprofit group that tirelessly promotes their good deeds. She points out that they are very intelligent for their size and that because many of them live in colonies, they have to cooperate to get things done. They may even form friendships, she says.

"As people learn more about bats and learn that they are not evil, rabies-spewing creatures, they still need to use caution," Sturges says. "I got too many calls this summer from people whose kid took care of a bat overnight. That shouldn't happen."

Bats can, though rarely, carry rabies, so never handle one barehanded. Anyone who wakes up in the morning and finds a bat in the house should assume that it could have had contact with a person and should call animal control to have the creature tested for rabies. Same if a bat is behaving oddly, such as crawling on the ground and unable to fly. (The group's Web site, www.batworld.org, has instructions on what to do -- or not do -- if you find a bat.)

Bats outdoors, even seen during the day, should generally be left alone, Sturges says, adding that they will not seek out people.

Her group takes in about 50 rescued bats annually, only from Virginia. This year, she raised and released 21 orphaned pups, feeding them a milk replacement, then graduating to mealworms and eventually flying insects that they know instinctively how to catch.

She also has saved adults found in strange situations. One red bat got caught in the retracting antenna of a car. The bat probably had been hit by the antenna while flying, and hung on when the antenna went down. The bat's wing tips were broken off and it cannot fly enough to catch bugs, Sturges said, but she plans to include it in education programs she runs.

Bats like to fly along a tree line or hedgerow so predators such as hawks cannot see them from above. Like hummingbirds, they move very quickly, navigating and catching prey via echolocation -- emitting high-frequency sounds that people cannot hear and that are reflected back to the bat in flight as echoes. That's why they don't crash into humans.

They fly with their legs stretched behind them. One way to distinguish bats from birds in low light is that bats don't have tails. Another is by the way they move.

"Birds glide, and bats don't," Sturges says. "If it's constantly fluttering, it's a bat."

-- D'Vera Cohn