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<<Back to Winter 2008-2009 Steward

Gone Batty!

by Katie Benzel, Dillon Field Office

biologists setting mist nets

Biologists set up a mist net over a spring area. 
Photo by Katie Benzel

big brown bat

Big brown bat. 
Photo by Katie Benzel 

Bats are an important part of the ecosystem, pollinating valuable crop plants and controlling night-flying insects. One little brown bat can catch up to 1,200 insects in one hour and reproductive females can consume their body weight in insects each night. A large colony of bats can catch literally tons of insects nightly, including beetle and moth species that cost American farmers and foresters billions of dollars a year. 

To get a better idea of which bat species occur on public lands within the Dillon FO, the BLM partnered with the Beaverhead-Deerlodge National Forest. The agencies used mist nets and acoustic ultrasound detectors, which record the bats’ echolocation, to conduct surveys in July and August. Dillon Field Office Wildlife Biologist Katie Benzel joined the bat crew for two nights at the end of August.   

The nets were hung across slow-moving/standing water where the bats come to drink and feed, and at the base of a cliff. Bats caught in the net squawked and hissed as they were untangled and taken to the makeshift processing table on the pickup tailgate. There, the crew took measurements such as forearm length, ear length, and weight, and noted statistics such as adult vs. juvenile, sex, and reproductive status. 

In addition, the crew took a biopsy punch from the wing for genetic identification of the species. Bat species caught these two nights were the little brown bat, big brown bat, silver-haired bat, and the long-eared myotis, which is on the BLM sensitive species list.

Bats are largely misunderstood and many people fear them; however, less than one-half of one percent of bats have rabies, and these typically bite only in self-defense. Bats pose little threat if you do not handle them. 

Having the rare opportunity to be so close to bats, I realized how interesting they are--from their echolocation capabilities (they can detect obstacles as fine as a human hair in total darkness) to their wings, which have four fingers and a thumb.  Although batting requires late hours (the first night we were out until 4 a.m.), I definitely have a greater appreciation and fascination for this little mammal that serves a big purpose. 
Did You Know?
  • There are more than 1,110 kinds of bats in the world, making up nearly a quarter of all mammal species. 
  • Bats are found everywhere except in the most extreme desert and polar regions.
  • There are 47 species of bats in the U.S. and Canada. More than half of the U.S. bat species are in severe decline or on the Endangered Species list.
  • For their size, bats are the slowest reproducing mammals on earth, making them vulnerable to extinction. On average, bats have one pup per year and don’t give birth until they’re at least two years old.
  • Bats are long-lived, with a few surviving more than 34 years. 
  • There are seven species of bats on the Montana/Dakotas BLM’s sensitive species list.



Last updated: 06-28-2012