Myotis lucifugus at Maternity Colonies in Massachusetts: Assessing
Impacts of White-nose Syndrome 

Katherine M. Gillman, Gordon Towne, Allison J. Harwick, Aaron Gatnick,
Thomas T.D. Little, Margrit Betke, Zheng Wu, Jonathan D. Reichard,
D. Scott Reynolds, and Thomas H. Kunz. 

Little brown myotis (Myotis lucifugus) populations in the northeastern
United States (US) have recently experienced major declines in many
hibernacula owing to the spread of Geomyces destructans, the fungal
pathogen associated with white-nose syndrome (WNS). For the past
several years, we have monitored two established maternity colonies of
M. lucifugus in Massachusetts using infrared cameras (BatCams) to
census bats. We present results from these two colonies for comparison
with colony sizes at other maternity roosts in the northeastern US
before and after the appearance of WNS. Weekly censuses were made
directly from the video recordings, along with live counts in the
field. Current analysis of videos from one site (Paxton) shows that
this colony decreased by 70% from 2008 to 2009, by 11% from 2009 to
2010, and by 5% from 2010 to 2011. The second site (Lincoln) decreased
by approximately 40% over each of the past two summers. Live visual
counts of emerging bats were comparable to counts made directly from
the video recordings. Automatic computer counts, made using a
specially developed program, were at times 20% higher than results
from the two visual counting methods (bats were sometimes difficult to
distinguish from insects in the near field). Relative to other
maternity colonies in the northeastern US, current results suggest
that these two colonies may provide refuges for unaffected bats or for
survivors of WNS. Similar results could be seen in other locations if
suitable roosting sites, such as specially designed roost modules, are
made available for small residual colonies.