by TNCave » Jun 7, 2011 10:13 am
Hi guys,
Sorry, I've been pretty busy lately and not on here for several weeks. There will be a complete presentation about the winter 2010-11 WNS surveillance at the TN Bat Working Group meeting at FCFSP on November 18, but I'll be happy to give a quick update.
As we are still learning how best to survey for WNS, we pushed back our survey efforts until Feb 15-April 1 this year. This gives the fungus time to grow and increases your chances of finding field signs of WNS. This comes at the expense of reduced bat numbers as our highest cave bat numbers are in January-early Feb. Much of our effort was on middle TN, looking for new/expanded sites. Outside of the Clarksville/Montgomery County area, there was no observed exansion of WNS in middle TN. Our first big site this year was in response to a local caver's entrance check of a known Mont. co. bat cave. She reported hearing bats in the entrance of the cave. Upon inspection, the cave was in pretty bad shape with some mortality and many bats showing advanced signs of fungal growth. The bats sent off were confirmed + for WNS by the NWHC in Madison. This cave is within 20 miles of the KY site that was confirmed later. We also saw field signs of WNS in another nearby cave in Mont. Co., but did not send off bats as the county has already been confirmed.
Other middle TN sites looked much like last year. Our caves that were G.d. positive last year showed little to no increase in % affected and mortality. Our north-east TN sites were more representative of what they've seen in the northeast U.S. with a much higher % affected this year and mortality documented in both sullivan and Carter counties. Much like year two for northern sites, our Sullivan county cave had a huge increase in the overall number of bats, but the % affected by WNS was greatly increased. The Carter Co. site had mortality, missing bats, and a much higher % affected. In the northeast, they count missing bats as mortality, but we are not doing that in TN yet. We only count them as dead if we see them. As scavengers pick them up pretty quickly, we mostly counted hanging dead bats.
As a note of caution, I should say that these observations do not represent a complete picture. This information is based on only 65 caves that people turned in data for, and a few of those were entrance checks. Although we have data for more caves overall in TN this year, we actually have less from east TN, where we might expect to see more signs of WNS than in other parts of the state. It is natural for all of us to draw conclusions from our observations, but I'll say that the information is limited in all regards. There are still many unknowns about WNS in general and 65/9600 caves is less than 1% of caves in TN. One thing also to keep in mind is that TN, especially middle and west TN are not the northeast. Our climate is different, our bats are sometimes different, even the same species of bats often have different hibernation strategies in the southeast than the northeast. Everything we know about WNS is based on how it is expressed in the northeast. I'm hopeful the south will be different, but for now, we have much to learn from a small annual window each winter.
Best Wishes,
Cory