Wood turtles on the verge at Great Swamp
The wood turtle wouldn’t strike most people as a charismatic creature.
Solitary and silent, with coloration designed for disappearance, the wood turtle was never meant to stand out. For thousands of years the species has existed as a fixture of once-abundant landscapes centered on meandering cobble-bottom streams and the fields and forests that surround them.
And yet, as nondescript as these animals are, a quiet charisma becomes clear to the careful observer. Turtles within a population seem to know each other. They hibernate together. Females acknowledge each other with graceful bows of the head, and willingly approach some males while avoiding others. Males patrol their own sections of the stream, excluding competitors and courting females. Turtles young and old are sometimes found inches apart, or even nose to nose. They are not the lonely creatures we imagine them to be.
Once you come to know these animals, you can see wisdom in their eyes. You develop a real sense that their absence from the landscape would leave a gaping void in the life of the land, like the passing of a loved one who had been the quiet, steady rock at the center of your daily existence.
In many places throughout the Northeast, the voids are real and haunting.
Their populations remain as fractured remnants on a landscape interrupted by suburban sprawl. Their streams, degraded by silt and erosion, are often flanked by paved death traps that mercilessly claim young and old with equanimity. The suburbs that have closed in on them bring raccoons, who munch on young hatchlings and full-grown adults alike. Facing substantial declines over the last century, wood turtles have been petitioned for listing under the Endangered Species Act, a decision the U.S. Fish and Wildlife Service must make by 2023.
At Great Swamp National Wildlife Refuge, wood turtles are on the verge of something entirely different.
A relic population discovered in May 2006 has been nurtured, tracked, and shepherded toward recovery. A journey 13 years in the making has been supported by $158,000 in donations from the Friends of Great Swamp National Wildlife Refuge, roughly $150,000 in federal dollars for staff support, and more than a dozen interns, staff and researchers who have tirelessly followed turtle movements. Over 450 young turtles have been released from nests armored against ravenous raccoons by wire cages. Hundreds of radio transmitters have been fitted to dozens of turtles. Absent the support of the Friends of Great Swamp National Wildlife Refuge and the refuge’s ability to serve as a catalyst, none of this could have happened — and any other conservation organization would be hard-pressed to emulate it.
But back in 2006, we had no idea what the future would be for this relic population. The turtles were living on private property with the threat of development.
We hoped to lure them to the wildlife refuge by building an artificial nesting mound. It worked, so we doubled the size of the mound in 2008. Two years later, the neighboring private land was sold to the refuge for turtle conservation.
But nesting habitat wasn’t enough. Predators would devour the vulnerable eggs and hatchlings. So in 2011, we started a program that would give hatchlings a head start, a safe place to grow bigger and stronger before returning to the wild. We followed the lead of Dr. Kurt Buhlmann of the University of Georgia’s Savannah River Ecology Lab and his work with Blanding’s turtles. With the help of natural resource students from Bristol County Agricultural High School, over 232 “head-start” turtle hatchlings have since been gathered from their natal mounds, spending their first nine months being hand-fed at summer temperatures while their wild counterparts hunkered down and slept through the winter. The head-starts achieved the size of 3-year old turtles in just nine months of life.
Just eight years later, the first head-starts have started to reveal whether this novel conservation technique can effectively turn the tide for a population in decline.
More of them do survive — in one analysis, we estimated 48% survival of head-starts compared to an expected 13% among their wild counterparts.
And those hatchlings are critical for the survival of wood turtles at the refuge. Adults started dying in 2014, with 10 lost to date. Just 6 adult females — and no adult males — remain.
Fortunately, males from the first class of head-starts began breeding in 2017, three years earlier than their wild counterparts, thanks in part to the boost in nutrition they received during their first nine months. The females reached adult size in 2019 at just eight years old — four years before their wild peers. Would the females, who are slower to mature, also begin breeding sooner?
In May of 2019, Dr. Kurt Buhlmann exuberantly called longtime project lead and Service biologist, Colin Osborn, with the answer.
Two females from the first class of head-starts, lovingly referred to as F464 and F465, had each laid their first nest!
But for all our excitement and all the potential held in those 32 square inches of loose sand on the nesting mound, after 13 years and $300,000, would hatchlings emerge from the nesting mound?
Sadly, it was discovered in late August that female F465’s nest was not viable, as is common with many first-time reproductive females, across many species.
On September 2nd, biologists investigated F464’s nest and found that some unknown critter may have made their home in the mound, much too close for comfort. Unsure what to think of the discovery, biologists rechecked the nest two days later.
And that’s when they found a sole hatchling. The first wild hatchling known to be successfully reared from the nest of a head-started wood turtle!
And so the circle continues. The hatchling was brought back to Bristol Aggie, along with 19 others form three other females, to be head-started itself. And in eight years, perhaps it will produce its own young at the refuge.
“Our goal with the head-start program is to give the population a boost so that one day, with continued habitat conservation, they are able to reproduce and maintain the populations on their own,” says Dr. Kurt Buhlmann.
For a species on the verge, the future for wood turtles at Great Swamp National Wildlife Refuge is looking hopeful.
Marilyn Kitchell is the Wildlife Biologist at Great Swamp National Wildlife Refuge in New Jersey.
