Brown bats, white noses, bad scene
Like any expectant mother, a little brown bat will seek comfort and security when it's time to deliver and nurse her baby. At Moore State Park, the bat maternity house, a small, windowless building at the edge of Eames Pond, provides just this kind of shelter for the mothers and babies who make the park their summer home.
Sadly, a fungus known as white nose syndrome is making inroads into the little brown bat population, and the park's summer visitors are no exception.
Dr. Thomas H. Kunz, professor of biology at Boston University, says the little brown bat population at Moore has seen declines over the past two winters.
"We don't know what's causing it," he says.
To find out, Kunz and his team last week installed a camera at the maternity house that will let the biologists get a good feel for the health of the colony, which they have been observing since 1979.
The bats mate at "swarming sites" in the fall and then hibernate over winter in caves and old mines in western Massachusetts, New York, Vermont and Pennsylvania. The bats should be arriving at their maternity sites in the next few weeks, Kunz says, where the mothers will give birth and nurse their babies (called pups) for 4-5 weeks.
Typically, Moore State Park's maternity house will have a population of 600- 900 moms and pups, Kunz says, but this year, they're predicting a 30-50 percent decrease.
It's not clear what is causing the white, fuzzy fungus geomyces that grows on the nose and sometimes the wing membranes of afflicted bats.
"It's not usual for a fungus to kill a mammal, but it can irritate and cause infection like athletes' foot does," Kunz said. "It's possible that the fungus is arousing the bats from their hibernation and that by midwinter, they've expended their fat."
The fungus invades the dermis of the bat's skin, and their wings become scarred and necrotic, making it impossible to feed or fly.
The fungus appears to be a relatively recent invader.
"It grows at around four degrees Celsius, which is the temperature of a bat hibernation cave," Kunz said.
Bat experts don't know the mechanism spreading white nose syndrome. While bats may be dispersing the fungus, it's possible that humans who explore the hibernation caves are carrying it on their footwear.
There are several hypotheses about the cause of the syndrome.
It could be related to climate change, a dryer climate causes a decrease in some insects, Kunz said. The lack of food may depress the bats' immune systems and leave them vulnerable to white nose.
This could be a natural variation or a global climate change, Kunz said, but added that he isn't blaming global warming.
"Global warming is just one hypothesis," he said. " It's used to explain everything. We don't have any data to suggest that global climate change is to blame."
While it's true that a nursing little brown bat will eat its body weight in insects, it's not true that they eat mosquitoes - though humans would probably appreciate it if they did.
Little brown bats eat pest moths that are bad for forests. Kunz said. They also eat insects that are bad for agriculture like potato beetles and cucumber beetles. The bats play an important part in the ecosystem.
As bat experts continue to search for answers to the fungus, they sadly note that government agencies aren't providing much help.
"The feds are dragging their feet on this," Kunz said. "We don't even have enough money for our summer funding."