Alabama experts conducting ‘culvert blitz’ in search for hibernating bats
Bat experts are exploring culverts across the state to gauge their importance as winter residences for bats. (Scott Lamont)
Multiple organizations and agencies continue cooperative efforts to learn more about the health of bats in Alabama.
If you happen to notice some folks with flashlights peering beneath bridges around the state this month, don’t call 911. They’re on a mission to identify where some of Alabama’s more mysterious and misunderstood animals are spending the winter.
Biologists with the Alabama Bat Working Group, along with experts from state and federal agencies, are fanning out across the state through February to conduct a “culvert blitz” – a variation on the annual Bat Blitz that takes place in Alabama each summer.
During the summer blitz, bat experts pick a spot in the state to conduct a detailed, multiday survey of the bat population in that area. They spend the overnight hours during the blitz capturing bats, counting them and examining them to determine their relative health.
This month’s culvert blitz is taking the experts into dark concrete culverts underneath bridges, which can mimic the conditions in natural caves where bats are historically found. Throughout the years, biologists have learned that some bats now choose these culverts for their winter roost.
The purpose of the culvert blitz: to get a better handle on which species of bats might choose to spend their winters hibernating in these manmade structures, and how important they are for these furry, flying mammals.
“These culvert surveys in Alabama are part of a larger effort that some neighboring states are also taking part in,” explained Dylan Shaw, a biologist at Alabama Power and a member of the Alabama Bat Working Group.
He said culverts, especially large ones where conditions can be similar to those in caves, “are proving to be an important winter habitat for a number of bat species in Alabama.”
Those species include the tricolored bat, which federal officials have proposed for listing as an endangered species.
“Since these areas aren’t commonly studied, there have been some exciting discoveries in recent years,” Shaw said. He noted that Alabama Power biologists recently identified a Rafinesque’s big-eared bat in a culvert in Greene County, the first to ever be found in that area.
He said tricolored bats, in particular, have been found in higher numbers in culverts. Sadly, the species has largely disappeared from caves and other natural settings because of the massive negative impact of white-nose syndrome (WNS), a disease with no known cure that has devastated bat populations in large sections of the U.S.
Experts on the prowl for bats in culverts as part of this month’s “culvert blitz.” (Scott Lamont)
The decline of many bat populations around the country has broad implications. While bats may seem creepy to some, they play a vital role as pollinators for plant propagation and crop production. They are also ravenous insect-eaters, helping decrease the numbers of annoying and potentially dangerous bugs, such as mosquitoes, while also protecting forests and agriculture from damaging pests.
While WNS has taken a grim toll on bats around the country, Alabama experts can point to the occasional bright spot.
The latest positive headline about bats in Alabama was first reported last October, when biologists with the Alabama Department of Conservation and Natural Resources (ADCNR), the U.S. Fish and Wildlife Service, and the Alabama Bat Working Group announced they had discovered a breeding population of endangered northern long-eared bats in coastal Alabama.
The bats were captured during last year’s bat blitz in May, which took place in May in Baldwin and Mobile counties. On the final day of the blitz, experts snagged a male and two pregnant female northern long-eared bats on a tract of land in Baldwin County held by the state’s Forever Wild Land Trust. The property is within the Perdido River Wildlife Management Area.
Until last year’s blitz, no northern long-eared bats had been documented in southwest Alabama.
A rare, northern long-eared bat captured in Baldwin County during the “bat blitz” in May 2023. (Dylan Shaw / Alabama Power)
The discovery prompted a second effort, one month later, to catch more northern long-eared bats at the Wildlife Management Area. During the second attempt, experts captured another male and a lactating female, indicating the female had given birth in the area.
According to ADCNR, northern long-eared bats were once one of the most common bats in eastern North America, but the species has been decimated by WNS, which affects hibernating bats.
Fish and Wildlife Service officials say WNS has resulted in declines of 97% to 100% in affected northern long-eared bat populations. Because of its precipitous mortality rate, in 2022 the bat was officially listed as endangered under the federal Endangered Species Act.
Nick Sharp is an ADCNR bat biologist and is on the leadership team of the Alabama Bat Working Group. In an article posted on the state conservation website outdooralabama.com, Sharp said this summer’s bat blitz targeted coastal Alabama because of recent discoveries of northern long-eared bats in coastal North and South Carolina.
He said the discovery of the rare bats along Alabama’s coast was “significant, as there are no caves in these locations and the bats apparently do not hibernate. Rather, they are active year-round and therefore not exposed to white-nose syndrome.”
Experts examine a rare northern long-eared bat after banding it for identification purposes during the “bat blitz” in Baldwin County. (Dylan Shaw / Alabama Power)
State conservation Commissioner Chris Blankenship, who also serves as chairman of the Forever Wild Land Trust board of trustees, said ADCNR “has been intentional about acquiring land along the Perdido River corridor” to expand the Wildlife Management Area. Blankenship said the discovery of northern long-eared bats “is further evidence of the importance of this land in eastern Baldwin County.”
Jeff Baker, an Alabama Power biologist long connected to the Alabama Bat Working Group, said the discovery of northern long-eared bats in coastal Alabama “highlights the importance of cooperative projects,” in which multiple public agencies, nonprofit conservation organizations, the private sector and individuals combine their resources and expertise for the common good.
“Research and wildlife professionals working together, like those in the Alabama Bat Working Group, make discoveries like this possible,” Baker said.
For more information about northern long-eared bats in Alabama, click here. To learn more about the Alabama Bat Working Group, click here. To learn about ADCNR’s bat monitoring and conservation efforts, click here.
