Tracking Bats in the Semi-Arid West

I am amazed when I look  out over the semi-arid desert, knowing that the harsh environment actually shelters a variety of wildlife. Hiking through rough scrub and dusty red soil, we scare up fence lizards and many-lined skink. We walk in the tracks of the wild/feral horses, and we drive carefully around blind curves to avoid the bighorn sheep on the cliffs. In the last few weeks, I have seen more owls than I’ve previously encountered in most field seasons. I was born and raised in the semi-arid west, but I am still impressed to discover the vibrant life dwelling in this land.

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Hiking with my field partner to a bat acoustic site (in a very stylish sun hat).

The wildlife that brings me and the Wyoming Natural Diversity Database (WYNDD) here are the bats. Wyoming is home to 16 species; we are interested in learning more about all of them, but particularly the Northern Long-Eared Myotis (Myotis septentrionalis), a species recently listed as threatened by the U.S. Fish and Wildlife Service.

When we catch M. septentrionalis in our mist-nets, we attach a tiny radio-transmitter to their back before letting them fly off again. We track them the next several days, climbing over valleys and hills in pursuit of their radio beeps, until we find their day roosting tree. We record habitat information, which we will accumulate until we have a better understanding about M. septentrionalis’ habitat use.

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The tiny transmitter is attached to a shaved portion of the bat’s back with a spot of glue. The transmitter will fall off on its own after a few days.

The other half of our bat work is placing acoustic detectors across the landscape which can passively record bat calls each night. These locations are random; they can be placed near water and therefore very active sites, or in the middle of a dry, barren dust-bowl. Bat calls can show up even in places where I am skeptical that anything lives at all. A good, clear recording of a bat call can be identified to species, since bat species have their own unique frequency and style of sonar. This way, we can gain an idea of the activity and species composition at a site.

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My field partner hikes to another acoustic site amidst prickly pear and yucca.

I enjoy both aspects of the work– experiencing the behavior of bats in hand, and recording their activity while they carry on undisturbed–and a combination of these tactics will tell us more about these special inhabitants of  the Wyoming landscape.

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A hoary bat captured in the Laramie Range in Wyoming.

 

 

 

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