08-28-13 Bat Field Note

08-28-13 Bat Field Note

August 28, 2013

Kate Stone shares a Field Note on efforts in conjunction with FWP to capture and study bats.

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Bat Field Note 8/26/13 Kate Stone Long-eared myotis

From August 19th-21st, we worked with Lewis Young, a volunteer from MT Fish, Wildlife, and Parks, to capture bats and to examine potential bat habitat. Kristi Dubois, the local nongame biologist for FWP, helped coordinate the efforts and helped with trapping on two nights. These efforts complement on-going bat acoustic monitoring. We set up nets and trapped for bats on three nights at three locations. Though we saw bats at both the floodplain and Whaley Draw sites, we did not capture any. Strong winds and heavy smoke the first two nights may have compromised the efforts.

Lewis suspected that this spring that spills onto the road in the Boondocks would attract bats for a drink. It offered clear access and relatively still, open water. We set up a net directly over the largest puddle and placed additional nets at either end of the flyway.

Lewis’s hunch proved correct. We found bats at the net each time we checked. On this check, I found four bats on arrival, and one more flew in as I extracted the others. Sometimes the distress calls of bats stuck in the net attract other bats.

Lewis processed the bats back at his truck, where he arranged the bats in paper bags based on their capture time (top). The procedure generated a lot of garbage (bottom) because of the need to guard against the potential spread of white nose syndrome. Lewis handled each bat with a different set of rubber gloves, and a different holding bag.

To distinguish a California myotis from a small-footed myotis, Lewis examined the amount of tail extending beyond the uropatagium. If it does not extend beyond, as above, it is a California. If it does extend beyond, then it is a small-footed myotis. The same California myotis, below, has an orange-colored mite attached to its ear.

Reaction to handling varied by species. A big brown bat, above, appeared relaxed and sleepy compared to a long-eared myotis that bared its teeth (below).

Lewis aged the bats by illuminating the joints of the wing in Debbie’s headlamp (top). The color and knobbiness of the joints indicate adult or juvenile life-stage. He also checked for wing damage that could indicate white nose syndrome (bottom). The photo below shows the hoary bat’s two-toned wing.

After processing, Lewis extended and gently waved his hand to prompt the bat to fly away.

We captured 28 bats of six different species. A few bats escaped from nets or out of bags during processing. The long-eared myotis and the long-legged myotis were the most frequent species captured. Lewis suspected a maternity roost nearby due to the number of female longeared myotis. This species might use a tree cavity or a rock crevice for roosting.

Insects found at night.

The night adventures also led to repeated observations of common poorwills (top) and western toads (bottom).

Lewis offered several suggestions for ways to improve water sources for bat drinking and safety. This large pool in Whaley Draw offers unobstructed access to bats. Some springs are closely surrounded by fencing to keep ungulates out. These fences make the water sources inaccessible to bats. Expanding the fencing even a few feet would allow bats to navigate close to the water.

The Lolo Creek fire smolders on the west side of the valley. Burned forests provide habitat for many species including bats; they roost under the dead bark of charred trees.

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