Vermonts rattlesnakes face new, unexpected threats
By Madeline Bodin | October 13,2013
Searching for his reading glasses, Doug Blodgett, a biologist with the Vermont Fish and Wildlife Department, does not look like a man on a mission. “Does it have a pre-button?” he asks, leaning closer to a small snake hidden behind a rock.
Jim Wilson, an amateur herpetologist who is Blodgett’s assistant on this day in late September, also has a pair of reading glasses perched on his nose. Both men agree that there’s a pre-button at the end of the snake’s tail, which is the start of this snake’s telltale rattle.
“That’s a neonate,” Wilson says, referring to a newborn snake that is less than 10 days old and has never shed its skin.
Blodgett’s mission is to rehabilitate the reputation of the timber rattlesnake in Vermont — a difficult task, considering that Vermont offered a bounty on its rattlesnakes as recently as 1971.
“Even bats have more friends than snakes,” he says.
Vermont’s rattlesnakes could use a friend. Western Rutland County is home to the northernmost population of the timber rattlesnake, one of 33 species of rattlesnakes native to North America.
“Maine already lost theirs,” Blodgett says of another northern timber rattlesnake population. “Rhode Island’s are already lost. New Hampshire’s are in deep trouble. Massachusetts still has a few.”
Because of decades of habitat loss, bounty hunting and capture for the pet trade, timber rattlesnakes are an endangered species in Vermont. Western Rutland County is the only place they are found in the state. Blodgett can’t say exactly how many rattlesnakes remain in Vermont. His best estimate is several hundred.
Life is tough for rattlesnakes so far north. In Vermont they may spend seven months of the year hibernating deep inside rock crevices. These hibernation sites are protected by The Nature Conservancy. But until recently little has been known of their summer whereabouts.
Two years ago, Blod-gett joined with The Orianne Society, a Georgia-based organization that conserves snakes, to study the Vermont rattlesnakes’ summer travels. The scientists captured 144 snakes and implanted passive integrated transponder tags in 22 of them. They also collected DNA samples.
They then tracked the tagged snakes, noting where the snakes were on the landscape and when.
What they found was surprising. Rather than wandering aimlessly, snakes seem to know where they are going.
“Their movements are direct and purposeful,” Blodgett says. Four months after they left their hibernation sites, the snakes returned using the same path.
On average, the snakes traveled about two miles from their hibernation sites.
The study has continued, and on this fall day Wilson readies the five-gallon bucket he has carried to the site while Blodgett wields a long metal grabber. With a gentle scooping motion, Blodgett moves the baby snake from behind the rock into the bucket.
The snake appears content in the bucket as Blodgett observes it for several minutes. Then he turns his back on the snake and the bucket, and records his observations in a small notebook.
Blodgett does not ignore the dangers rattlesnakes pose. He wears protective gaiters to protect his legs against bites and is careful to never put his hands on the ground, even on steep slopes with loose rocks.
Before heading into rattlesnake territory, he reviewed the emergency procedure with Wilson. In case of a bite, the nearest antivenin, or anti-toxin to venom, is at a hospital in Glens Falls, N.Y.. A man was bitten by a rattlesnake in 2010, the first time that had happened in over 50 years. The man recovered.
Mostly Blodgett emphasizes how shy and tolerant rattlesnakes are. “They will do anything to avoid confrontation,” he says.
The snakes’ warm and fuzzy side, metaphorically speaking, doesn’t end there.
“Rattlesnakes are good mothers,” Blodgett says.
They bear their young alive and stay with them through their first few weeks of life. After a baby snake sheds for the first time, mother and children part ways, each trying to capture at least one meal of a mouse, vole or chipmunk before they begin hibernating.
A rattlesnake has about a 50 percent chance of surviving its first year, Blodgett says. The long-term odds may be worse for Vermont snakes because of two new threats discovered in this study.
One is a genetic bottleneck. Despite the fact that the Vermont population includes two distinct color phases — some snakes have a yellow background to their scale patterns, while others have a black background — the snakes have lower than expected genetic diversity.
The second threat was noted when deformities from a fungal infection were found on some of the snakes. This fungus, which has killed snakes in the Midwest, doesn’t seem to be as lethal in the Vermont snakes, Blodgett says. But the fungus has been confirmed in rattlesnakes in Vermont and is suspected in garter snakes and Eastern rat snakes.
The latest phase of Blodgett’s study has two goals. The first is DNA testing of the snake fungus. One of Blodgett’s and Wilson’s tasks for the day is to collect scale samples from any snake they find that appears to have a fungal infection, so that the fungus’s DNA can be tested. The snake in the bucket appears sleek and healthy, however.
The other goal is to find out more about the rattlesnakes’ reproduction and survival. This snake’s existence is proof that at least one litter of rattlesnakes was born in Vermont this year, but Blodgett says that that’s not enough information for any meaningful conclusions.
With the snake’s role in the study completed, Blodgett tips the bucket to set it free. The snake slithers into the dappled shade of an oak tree and disappears against a background of leaves and rocks.
Blodgett watches it go. Knowing the long odds the young snake faces, he calls after it, “Hope to see you next year.”
Madeline Bodin is a freelance environmental journalist who lives in Andover. She can be contacted at firstname.lastname@example.org.