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Bald eagles, bears and ... bats?

Posted: Monday, November 08, 2010

The Alaska Department of Fish and Game is undergoing a pilot study on bat behavior through the Wildlife Diversity Program.

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Michael Penn / Juneau Empire
Michael Penn / Juneau Empire

"We know very little about bats here," said Karen Blejwas, a regional wildlife biologist for the Wildlife Diversity Program who's conducting the study.

Blejwas said bats are a mystery in Southeast Alaska, with little known about behavior or migratory patterns. Many people don't even know there are bats in the Southeast at all.

"There's a limited understanding of where bats are found and where they're distributed in the landscape here," she said, explaining it must be researched whether bat species are found only in certain spots or if they are spread out more. Therefore, a study began in the spring and continues now.

The Wildlife Diversity Program borrowed three AnaBat detectors from the Forest Service from Chugach National Forest to do a combination of active and passive monitoring.

For active testing, researchers walk a trail with the AnaBat after sunset to pick up echo location signals that bats produce. Blejwas said she's done this on 32 trails in Juneau and found bats on all but one.

She said the findings were widespread but in low densities, with some "hotspots" located at certain times of the year that change over the course of a season. "Hotspots seem to be in the (Mendenhall) Valley," she said, giving other examples like in lower Montana Creek, the Airport Dike Trail and the Auke Lake Trail.

For passive testing, timed detectors are set up near known maternity spots, such as those in Auke Bay or near Twin Lakes. These boxes turn on about an hour before sunset and record throughout the night.

"So we're able to look at activity patterns and when bats are most active and when bats first show up in the spring and disappear in the fall," said Blejwas.

She said activity readings dropped in mid-September, but still pick up the occasional bat.

Blejwas said the study could help researchers learn where bats hibernate in the winter and swarm and roost during other times of the year. She said many bats may stay in the Southeast as it doesn't get as cold here as in other areas.

"It wouldn't surprise me of we had some bats from the interior or Canada hibernating here.

She said there are many spots locally that present good hibernation spots, such as caverns, decaying trees and rock crevices. She cited a cave on Prince of Wales that bats are known to use.

She said the study could also help distinguish local bat behaviors from those of the same species in the lower 48 states.

Another important aspect of the study is that a disease known as white-nose syndrome has been killing bats down south and it's important to locate hibernation spots to monitor if the disease will eventually make it's way here, she said. White-nose syndrome hits little brown bats the hardest and that's the most common species here, so it's important to find out where they are in order to help prevent the disease.

The Wildlife Diversity Program is getting the public involved in the study. Flyers have been circulating asking those who have seen bats, particularly three or more in a group, to call in. Blejwas said the significance of this number is that three or more bats indicates a nearby roosting area. She said typically only one or two bats are seen at a time.

Blejwas hopes to expand public involvement with volunteers monitoring trails next year. She said training sessions could be held in the spring.

She said Fish and Game is also working on its bat observation website to expand into Southeast Alaska, and that should be updated within the next few months.

She is also working on a proposal based on this study to extend monitoring to other Southeast communities and hopes to progress into capturing and radio tagging bats to find out where they spend winters.

Blejwas said there are five species in the Southeast. The little brown bat, Keen's myotis and California myotis are found in Juneau. The long-legged myotis is found around Wrangell and Petersburg. She said another local species is the silver-haired bat. She said the only specimens found of this one have been female and have only been found in wintertime.

Blejwas said the little brown bat is not only the most common bat in Southeast Alaska, but is also the only species around that crosses into the interior of Alaska.

Blejwas said she's also heard of some bat sightings offshore near Prince of Wales Island and would like to find out more if there is really activity there.

Those who would like to report bat sightings or are interested in aiding the study may contact Blejwas at 465-4328 or karen.blejwas@alaska.gov.

• Contact reporter Jonathan Grass at 523-2276 or at jonathan.grass@juneauempire.com.



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