Bats Offered Alternative to Haunted Houses

By Bonnie Stevens

This time of year we often associate bats with haunted houses, but houses don’t have to be haunted to attract these creatures of the night. Wildlife biologists say the large, standing dead ponderosa pine trees that many bats prefer are not abundant in our Southwestern forests anymore. So instead of crawling under the loose bark of snags to roost or raise their young, bats may be choosing to live with you, under the eaves of your home.

To solve this shortage-in-bat-housing problem, Northern Arizona University School of Forestry graduate student Liz Mering is introducing bat condominiums to the forest neighborhood.

“We have two kinds of artificial roosts that mount onto the trunks of large trees and mimic the exfoliating-bark characteristics of dead, old ponderosas pines. One is made of wood and looks like a one-foot by one-foot wedged box. The other is made of resin. It’s molded and painted to look like bark.”

Mering has posted 104 artificial roosts in trees around Flagstaff in the last two years. Half are wooden; half are resin. She says it’s too early to tell which kind the bats like better, but wildlife biologists prefer the resin roosts. They are made of the same material you find in boats, so they’re durable, lasting as long as the bats themselves, up to 30 years in the woods. And because they look so much like the bark of a ponderosa pine, they are fooling both the bats and their predators.

Unfortunately, they are also expensive, about $50 each. Noting the importance of bats in the ecosystem, the Forest Service has purchased 50 of these to ofer bats more habitat.

“Bats have gotten a bad reputation because people often associate them with rabies,” says Red Rock Ranger District Wildlife Biologist Janie Agyagos. “But less than half of 1 percent of the bat population actually carries the rabies virus. Instead, bats provide many benefits to the forest.”

Those benefits include fertilizing the soil with their guano, pollinating certain plants, and the big one, eating a lot of insects.

Of the 28 bat species squeaking and echo-locating across Arizona’s dark skies, 20 different kinds live in northern Arizona. Most weigh less than half a Hershey’s chocolate bar, but these ravenous nocturnal creatures are eating far more than their weight in pests.

“One bat can eat 600 mosquitos in an hour,” says Agyagos. “The desert pallid bat found in Sedona can pick up scorpions and millipedes off the ground and fly away with them.”

Keeping up with that appetite is exhausting, so finding a safe place to rest is critical to the bats’survival.

“We have a lot of trees in the forest, but not a lot of big trees,” says NAU School of Forestry Wildlife Ecology Professor Dr. Carol Chambers. “The bats we are studying are using trees with 25- to 30- inch diameters. With human-caused changes to the forest structure during the last century, we don’t have as many big, old trees as we once did, trees that will die and become bat habitat. While forest restoration efforts eventually will result in more big old trees, we’re hoping to be able to provide viable bat habitat in the meantime.”

By attaching a large bag that looks like a wind sock to the bat boxes, Mering is able to briefly capture the bats when they leave the roosts and examine them for disease and gender.

“We’ve gotten a lot of use based on mostly non-reproductive single bats. We’re hoping in a few more years we’ll get more use as many bats find them and remember them.”

If female bats set up maternity colonies and begin raising their pups in the artificial bat homes, researchers say they’ll have found a solution to the current lack of natural bat housing.