Emily Brunkhurst: (603) 271-2461
Jane Vachon: (603) 271-3211
July 10, 2009
White Nose Syndrome Affects N.H. Bats this Summer; Peterborough Colony Decimated
CONCORD, N.H. -- The deadly White Nose Syndrome (WNS), a new disease affecting hibernating bats throughout the Northeast, appears to be affecting bats in New Hampshire this summer. Hundreds of thousands of bats have died over the past three years in states from New Hampshire to Virginia. A bat colony in Peterborough has sustained a catastrophic level of deaths, and reports have come in from several New Hampshire towns about young bats dying.
Biologists from N.H. Fish and Game's Nongame and Endangered Wildlife Program and all across the region are involved in tracking WNS, which was discovered just three years ago and appears to be nearly always fatal to bats. Affected bats usually have a characteristic white fungus on their muzzles, wings and tails, but only in the caves and mines (hibernacula) where they spend the winter. The bats use up their stores of body fat, which is all they have to survive the winter, become emaciated and die. Hundreds of thousands of little brown bats and five other species have died, from New Hampshire to Virginia.
"Since so many bats have died, we expected to see declines in some maternity colonies," said New Hampshire Fish and Game wildlife biologist Emily Brunkhurst, "But the other effects we have seen have been surprising and sad."
Dr. Scott Reynolds has been studying a maternity colony of little brown bats in Peterborough, N.H., for over 15 years. It is the longest-running study of these colonies, where female bats gather under the roof of a barn or attic, where it is nice and hot, to bear and raise their pups. Each female normally gives birth to just one baby. After banding more than 4,000 bats over the years, and despite knowing that some of his banded bats were found dead of WNS in hibernacula in Vermont, Reynolds was still shocked to discover how WNS had devastated this colony. "I expected a decline, as there were 20% fewer last year than there had been before," he said, "but this year there are almost no bats; the colony is functionally gone."
The Peterborough colony has averaged about 2,000 bats over the last 15 years, and has been in existence for at least 40 years. There are now fewer than 100 bats left, and they have lost the advantages of a big colony. "Bats save a lot in energy by clustering together, passively maintaining a high body temperature," says Reynolds. "Now they need to spend a great deal of their energy budget on heat, and thus have a reduced growth rate. This spring the pups seemed to be healthy and growing fast, but they have now all disappeared. We don't know what happened."
Brunkhurst said, "When I heard of the loss of the Peterborough colony, I was shocked. We all understood that thousands of bats had died, and that the possibility was there that we would see great losses, but this just brings home the possibility, or maybe likelihood, that our summer skies will soon be fairly devoid of bats." Already Fish and Game has received many calls and emails that ponds once busy with bat activity, and barns where bats had traditionally roosted, are empty.
One surprising effect is that female little brown and big brown bats are abandoning their pups in greater numbers than ever before, according to Brunkhurst. One barn in Amherst, N.H., had over 16 babies come down, and, although 13 were rescued and taken to a wildlife rehabilitator, all died. This is also true of barns in Durham, Epsom, and Dunbarton, N.H., as well as colonies in Vermont, Connecticut, Virginia and other states. Susi von Oettingen, biologist with the US Fish and Wildlife Service (USFWS) said, "I'm puzzled by the unexpected pup mortality. Our preliminary observation is that the pups are emaciated, but we do not know if this is an effect of WNS or of the wet weather or some unknown cause." Dr. Reynolds plans to look at his long-term data to predict what mortality such a wet spring would be expected to produce, and compare it with the actual numbers to see what the effect of WNS might be.
New Hampshire. Fish and Game has teamed up with Vermont Fish and Wildlife to collect information on sick bats. If you find a dead bat this summer, or notice the absence of bats where they typically are seen in abundance, report it on the online reporting form hosted on the Vermont Fish and Wildlife website: www.vtfishandwildlife.com/Sick_Acting_Bat_Citizen_Reporting_Form.cfm.
Researchers have been working hard to learn as much as possible about this disease, but there has not been enough funding to get everything done. So far they have discovered that the fungus on the bats is new to science. It has been aptly named Geomyces destructans by its discoverer, Dr. David Blehert and his colleagues. It is not known whether the fungus causes the bats to become emaciated during the winter, or if something else is killing the bats. Recent funding through the USFWS State Wildlife Grant Program has provided some resources for states to respond to this problem through monitoring of bats, and research and management of bat habitat, especially the hibernacula. Response to a Nongame Program special appeal last fall provided donations that funded surveys of caves and mines in New Hampshire for WNS last winter. A new USFWS grant will fund research into mortality, disease spread and containment or population effects of WNS. Some possible projects include discovering if known treatments for fungal diseases can control WNS, finding ways to build resistance to the disease in bats, understanding the population effects of WNS and searching for causes other than the fungus. Several New Hampshire bat researchers are involved in projects to help in learning more about and controlling WNS. Congress has recently taken an interest in this fast-moving problem, but there has been no additional funding forthcoming as yet.
Meanwhile, one of the traditional sights of summer may be less visible in New Hampshire this year. "The little brown bat - the one most affected -- is the bat we often see cruising over a pond, eating insects," Brunkhurst said, "Bats eat thousands of pounds of agricultural pests and nuisance species like mosquitoes every summer. It is very alarming to think how this huge drop in the bat population will ripple through the ecosystem, and possibly affect our food production and timber industries."
Find more information and links on the N.H. Fish and Game Department's Nongame and Endangered Wildlife Program website at wildnh.com/Wildlife/Nongame/bats.html.
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