The Lost Generation?
To find answers, National Wildlife Health Center scientists are performing necropsies on nearly a hundred bat carcasses, and many other labs are following suit and eagerly awaiting results.
"Labs have done that first level of analysis looking for known pathogens or obvious contaminants—[something in the] physiology that might indicate an infection of some sort," said Susi von Oettingen, an endangered-species biologist with the U.S. Fish and Wildlife Service in Concord, New Hampshire.
"Many of these bats were malnourished, dehydrated, basically starving, [but] otherwise seem to look normal."
Meanwhile the bats that have emerged from hibernation this spring, especially pregnant females, offer a new opportunity to decode white-nose syndrome—or at least find out how devastating it has been over the winter.
"Most females [mate] in the fall [but utilize] delayed gestation. They emerge pregnant, and then the fetus starts to grow once they reach their summer habitat," von Oettingen said.
"The female bats that survived and emerged, are they going to have enough strength to have offspring?" she asked.
Because bats typically have only one pup a year, they are in a poor position to recover from population plunges.
Bat Barn Key Study Site
An otherwise unassuming barn in Peterborough, New Hampshire, is one of the key sites that may help experts answer their many questions about the affliction.
Independent bat expert Scott Reynolds, a teacher at St. Paul's School in nearby Concord, has studied and tagged little brown bats (Myotis lucifugus) at the site for 15 years.
The barn is a maternity habitat. In summer it fills with female bats that have hibernated all winter in far-off caves or mines. (Related: "Bats Use Magnetic "Compasses" to Navigate, Study Says" [December 6, 2006].)
This winter, four bats from the Peterborough barn were found in hibernation sites, or hibernacula, in New York and Vermont where white-nose syndrome was reported.
But the vast majority of the bats in Reynolds's long-term study hibernate in areas unknown to humans. During some 14 years of banding the barn's bats, only a handful have ever been found in hibernacula.
"Because we've gone into every hibernacula that we know of in the Northeast, we presume that at least 2,000 [bats from the barn] are living at any one time and we can't find them. Huge populations are wintering somewhere that we don't know about," Reynolds said.
"Is white-nose syndrome localized at the [two dozen-odd] sites where it has been discovered? Or is it much more pervasive and these hibernation sites that we don't even know about yet are going to get wiped out?"
In early June, when Reynolds begins to revisit the little brown bats, the Peterborough barn and other oft-studied sites may provide some answers.
"If numbers are down a lot, it means that even these hidden hibernacula are under threat, and [the ailment] is even bigger than we think," he said.
The prospect is unnerving. Reynolds warned that the Northeast's bats are facing their gravest known threat.
"If this is transmissible, it could really wipe out the flying, nocturnal insectivores section of the ecosystem."
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