Uncover mysteries of region's bat species

Local biologist hopes to engage community in citizen science

Posted: Friday, March 18, 2011

Fruits and flowers ripen into lush, succulent shades, bodies of water, gleaming and still, trees swaying rhythmically across a sultry twilight — such images are the stuff of holiday brochures and postcards.

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These scenes also depict an environment in which most of the world’s 1,000 species of bats live and thrive, where they have everything they need: seeds, insects and a variety of places to roost.

Although 70 percent of bat species choose to live in tropical climates, there are five species that call Southeast home: Keen’s long-eared bat, long-legged myotis, California bat, the silver-haired bat and the little brown bat.

The most common of these is the little brown bat, Myotis lucifugus, which is the only bat species that not only resides here, but also ventures up to Southcentral and Interior Alaska. The little brown bat is about nine centimeters long, with fur ranging from cinnamon to dark brown and ears that, when laid forward, nearly reach the tip of the creature’s nose.

“It’s definitely a stretch for bats to survive and reproduce in this climate,” said Karen Blejwas, a regional biologist based in Juneau. “But obviously, some bat populations have done it.”

Blejwas, who works with the Wildlife Diversity Program at the Alaska Department of Fish and Game, will be presenting “Bats in the Backyard: Flyers in the Forest” this Friday as part of the Mendenhall Glacier Visitor Center’s Fireside Lecture Series.

“We are delighted to have Karen share her research about bats and to give our audience the opportunity to participate in a citizen science project,” said Laurie Craig, an interpreter at the Visitor’s Center and the coordinator of its lecture series.

For those who have never heard the phrase, what is “citizen science”?

“That’s the term used when citizens contribute their careful observations and data collection to scientific study,” Craig said.

This data, Blejwas said, helps scientists gain a greater understanding of a species that represents more than 20 percent of the world’s classified mammals.

“It is amazing to me how much we don’t know about bats in Alaska, how much we don’t know about their distribution,” she said. “The fact that the little brown bat is fairly widespread throughout Alaska might surprise people — a lot of people, even long-term residents, aren’t even aware that there are bats in Southeast.”

And once people realize they are sharing our region with bats they may be curious about their neighbors: Exactly how many bats live in Southeast? Where do they roost? Do they leave for the winter or do they hibernate here? And when do they reproduce?

Scientists don’t yet have complete answers to these questions, and, due to this lack of information, Alaska’s State Wildlife Action Plan has identified the state’s five species of bats as species of concern.

“Bats are hard to study in Alaska, because they don’t occur in high densities,” Blejwas said. “Out East, there are huge numbers gathered in caves this time of year, but here, we don’t know what bats do in the winter.”

That’s where local citizens come in.

Simply calling in when you see a bat, and reporting its location, can help researchers gain a greater understanding of where bats are at any given time. Once biologists know basic distribution patterns of bats, they will then have a baseline for monitoring summertime populations, to see if the number of bats here are growing or getting smaller.

Blejwas, who is heading a study of bat behavior that encourages citizen involvement, says so far about three dozen people have volunteered information about bat sightings and roosts. These observations are being compiled into a searchable database.

And soon people in Juneau will have a new way of gathering information about bats, by becoming involved in a Citizen Science Acoustic Monitoring project.

“Not only can they report roosts, but they can take out the bat detector and count bats,” Blejwas said. “The timing wasn’t good to develop an acoustic monitoring program last summer, but this spring we want to involve people in more formal ways.”

Blejwas said she has four bat detectors available for mobile surveys.

“These are frequency-division detectors — they convert the high frequency bat calls to a lower frequency within the range of human hearing, so you can hear the bat while you are surveying,” she said. “The detectors also record the calls, with a date-time stamp, so you can look at a time-frequency graph of the call later on a computer.”

Groups of friends or families can check these out, and take them along designated trails.

“It’s a lot of fun — people can get together, walk a trail, and learn about bats.” Blejwas said.

The designated trails are located throughout Juneau and Dougas, and are of different lengths and degrees of difficulty — meaning, Blejwas said, that “there is something for everybody” who would like to participate.

The Wildlife Diversity program is supplementing the work of portable bat detectors with tasks performed by stationery monitors.

Right now, there are four of these monitoring stations set up — one each at Auke Bay, Auke Lake, Jensen-Olsen Arboretum and Twin Lakes — and eight more monitors are scheduled to be set up over the next two weeks. These monitors record night sounds to establish the activity patterns of the bats they detect.

So once researchers compile these various sources of information to learn more about what bats here are doing during the summer months, how will they learn more about where these creatures go in the winter?

Blejwas said when biologists know where the bats are roosting, they will have a better chance of trapping a few of the animals in late August so they can be radio-tagged.

“We hope to track them back to their winter hibernacula,” she said.

Citizen science contributes to biologists’ ability to better serve a creature as mysterious and as misunderstood as the little brown bat.

And it allows people to learn more about local wildlife in a way that engages both mind and spirit.

“Learning about our environment is great fun; being able to focus our efforts on a particular species makes our efforts more meaningful,” Craig said. “It helps us pay closer attention to the world and creatures around us. Understanding leads to appreciation, which leads to caring and respecting.”

• Amy Condra is a freelance writer based in Juneau, Alaska.





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