CNHP studies little brown bats to understand stability of populations in Colorado

by Rob Schorr and Jeremy Siemers, CNHP Biologists

In 2006, a new disease called White Nose Syndrome (WNS) appeared in New York that decimated bat populations.  This disease, caused by a cold-loving fungus, appears as a white dusting on the nose of bats has progressed westward as far as Missouri, and there is fear that it will continue its deadly march through to Colorado.  Yet, if it did, would we know? The nocturnal and secretive nature of bats makes monitoring their populations challenging.  That, in addition to the fact we have little knowledge of where many bats overwinter in Colorado, would make detection of a WNS-induced decline would be all but impossible to identify. There may be an alternative, however.  We may be able to monitoring summer (breeding) populations of bats to identify population-level declines.

Bats in flight around ranch house on a star-filled night
(Photo by George Fargo)

CNHP biologists, Rob Schorr and Jeremy Siemers are collaborating with Colorado Parks and Wildlife, the Yampa Valley Land Trust, and The Nature Conservancy to monitor little brown bat (Myotis lucifugus) populations at 2 ranches in the Yampa Valley.  This summer Schorr and Siemers marked nearly 600 bats with passive integrated transponder (PIT) tags and will return in 2015 to determine how many of the bats return and use the area annually.  This level of monitoring will provide insights into population stability for a healthy population of little brown bats in Colorado.

Schorr releases a female little brown bat after marking (Photo by George Fargo)

Jeremy Siemers and Rob Schorr assembling a 12-foot-tall harp trap
for capturing bats (Photo by Paul Cryan)