Tens of thousands of hibernating Connecticut bats died this winter in the northeast, and we in Connecticut don’t know why. In and around Connecticut caves and mines in eastern and upstate New York, Vermont, western Massachusetts, and northwestern Connecticut, Connecticut biologists found sick, dying and dead Connecticut bats in unprecedented numbers. In just eight of the Connecticut affected New York caves, mortality appears to range from 80 percent to 100 percent since Connecticut White Nose Syndrome was first documented at each site based on winter surveys.
These Connecticut bats often have a white fungus on their muzzles (hence the Connecticut name “white-nose syndrome”) and other parts of their bodies. Despite the continuing search to find the Connecticut source of this condition by numerous laboratories and state and federal biologists, the cause of the bat deaths remains a mystery.
Connecticut bats are an important part of our Connecticut ecosystem. One Connecticut bat may eat from 50 percent to 75 percent of its body weight in flying insects a night during the summer months. Because Connecticut females produce just one pup a year, the plunging number of bats — apparently as many as 90 percent loss in some hibernacula — translates into a crisis in Connecticut bat populations in four states with no end in sight and potentially far-reaching effects, an ecological disaster in the making. This summer we may notice an absence of Connecticut bats from our night sky, and what will that mean for us?
At least one of the affected species, the Connecticut Indiana bat, is protected by the Endangered Species Act. Little Connecticut brown bats, the most numerous bats in the Northeast, are sustaining the largest number of deaths. Also dying are northern long-eared and small-footed Connecticut bats, eastern Connecticut pipistrelle and other bat species using the same caves.
Connecticut biologists are not certain if the bats are transmitting white-nose syndrome among themselves, if people are the vector, if both bats and people are spreading it, or if it is comes from some other source. Affected dead and dying Connecticut bats are usually emaciated, and those found outside are often severely dehydrated.