Unfortunately, North American bat populations have been struggling to overcome the impacts of a new disease (white-nose syndrome; www.whitenosesyndrome.org), moralities at wind energy facilities (http://www.batsandwind.org/), and declines in insect prey (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185809). These challenges have bat biologists and conservation biologists scrambling to figure out how best to maintain populations of these nocturnal wonders. Yet, strategizing for these threats requires an understanding of the natural history and population ecology of these poorly-understood species.
Zoologists Rob Schorr and Jeremy Siemers of the Colorado Natural Heritage Program are trying to fill in the blanks regarding population dynamics of one of the bats most affected by white-nose syndrome, the little brown bat (Myotis lucifigus). For 3 years, Schorr and Siemers have been conducting mark-recapture studies of little brown bat maternity colonies in northwestern Colorado, and, in 2017, recruited two ambitious Colorado State University undergraduate researchers to understand what other roosts little brown bats use. These talented undergraduates (Kira Paik and Toryn Walton) tracked little brown bats that were fitted with small radio-transmitters. They discovered that the bats tended to return each night to roosts that are within a couple miles of the main maternity colony.
In addition to following them around, the researchers decided to get a peek at what these bats see from these newly-discovered alternate roosts. They employed a DJI Phantom 3 drone to take video from above each roost to look at the surrounding landscape. Although difficult to quantify, the video (this one from the main maternity colony) reveals what might be interpreted as a “neighborhood” with most roosts within sight of each of each other (within <2 miles). It is unclear why little brown bats return to roosts within close proximity, but it may have something to do with access to cohorts, available prey, and water resources.
See the CNHP drone in action the video below!