On a sunny April morning, Bryan Windmiller, director of conservation for Zoo New England, and I sat about 10 feet apart on two “socially distanced rocks” next to a brook in a suburb west of Boston.
As I interviewed Windmiller about the wood turtle conservation project he’s working on, Matt Kamm and Julie Lisk, both biologists from the Zoo New England Conservation Department, were about 50 feet away looking for turtles on the other side of the brook.
Suddenly Kamm yelled, “Hey! We got one!” and held up a large wood turtle.
Turtle in hand, Kamm and Lisk waded across the brook in their waterproof dry suits through the 3-foot-deep, 50-degree water to an open area on the bank where they could weigh and measure the turtle. It was a male, with a shell that measured about 7.8 inches long, which is close to the maximum size for wood turtles.
The turtle’s legs and neck were orange. The top of its shell, called the carapace, had enlarged scales, called scutes, that had concentric ridges and were pyramid shaped, looking like they’d been carved from wood. Windmiller said their wood-like appearance is probably the source of the wood turtle’s name.
Windmiller pointed out a large scar where a chunk was missing from the side of the turtle’s shell.
“It was probably hit by a mower blade in a field when it was young,” Windmiller said.
Launched in 2019, the wood turtle conservation project aims to assess the status of selected populations in Essex and Middlesex counties and design and implement plans to help protect and restore them.
Zoo New England is partnering with the state Division of Fisheries and Wildlife, which is funding the three-year project.
“Wood turtles are of conservation concern throughout New England, but they’ve been particularly hard hit in the area around Boston,” said Massachusetts State Herpetologist Mike Jones, who is supervising the project. “It’s clear that most wood turtle populations within I-495 have been extirpated. However, there are a few populations clinging to survival."
The goal is to build partnerships with local communities "to identify key management actions, while giving populations a little boost through nest protection and head starting efforts,” Jones said in an email.
Wood turtles are listed as a “species of special concern” by Mass Wildlife. The primary cause of their decline in eastern Massachusetts has likely been habitat fragmentation — new roads, development, and urbanization ― as well as degradation of waterways and streams, Jones explained.
“It's rare in the eastern part of the state to find sufficiently large and diverse landscapes to support thriving wood turtle populations,” said Jones.
In addition, for at least 50 years wood turtles have been targeted by collectors, as biological supply items in the 1960s and 1970s, and more recently as high-end pets, said Jones. It is illegal to catch or keep wood turtles.
Wood turtles, which can live 60 to 80 years, spend a lot of time wandering around on land during the summer months searching for food, Jones said.
The propensity to leave their streams and walk around makes them vulnerable to getting run over by tractors and mowers in fields and agricultural land, and by motor vehicles on roads.
Wood turtles are omnivorous, eating things like insects, slugs, and worms, as well as mushrooms and berries, Windmiller said.
They have an unusual way of catching worms.
“They rhythmically stomp on the ground to mimic the sound and vibrations of heavy rains,” said Windmiller. “This tricks worms into surfacing because the worms think they’re going to drown, and the wood turtles grab them when the worms come to the surface.”
Female wood turtles need open, sunny, sandy areas to dig their nests.
“There are few good nesting sites,” said Windmiller. “Many nesting sites are human-made clearings.”
Some of these clearings, like a baseball field next to the brook we were sitting near, may have litter that attracts skunks, raccoons, and foxes that eat turtle eggs and hatchlings, said Windmiller. And chipmunks, which also eat hatchling turtles, are abundant in the suburbs.
Windmiller said 21 adult wood turtles, mostly females, are currently being tracked by radio transmitters attached to their shells.
“They usually nest at the end of May,” said Windmilller. “We track them at night to their nesting areas. Then we put flat metal screens over the nests to protect them from nest predators.”
Wood turtles typically lay six to eight eggs, said Windmiller. To further protect the eggs and hatchlings, the researchers dig up the eggs about 50 days after they are laid and incubate them indoors until they hatch. They incubate 60 to 80 eggs.
Most of the hatchlings are returned to the wild, but 20 of the baby turtles are distributed to schools and other locations for head-starting, a process that involves raising the turtles indoors over the winter. This allows most of the head-started turtles to grow to about 7 ounces in weight and over 4 inches long — the size of 6- to 7-year-old wild wood turtles — by the time they’re released in early June, said Windmiller. Their bigger size decreases the likelihood they’ll be eaten by predators and gives them a greater chance of surviving to adulthood than smaller wild hatchlings.
Schools participating in the head-starting program include the McCarthy-Towne Elementary School in Acton, Ephraim Curtis Middle School in Sudbury, Greater Lowell Technical High School in Tyngsborough, and several others.
One of the major predators of adult wood turtles are otters, Windmiller said. A technique to help protect wood turtles from otters involves dropping logs into the water.
“Turtles like to hang out under logs to be safe from otters, which are the number one natural enemy of older wood turtles, especially in winter when the turtles are slow,” said Windmiller. “The otters will sometimes prey on the turtles and bite their heads and legs off. It’s common to find wood turtles without a leg. This is due to otters in most cases.”
“Turtles in general are animals that have been on earth for about 230 million years,” said Windmiller. “They are tremendous survivors.”
If anyone sees a wood turtle in Middlesex or Essex counties, Jones and Windmiller ask them to please take photos of the turtle and text them to the Zoo New England Conservation Department at: 508-970-9453 or email Windmiller at: email@example.com. People also can report sightings with photos to the Massachusetts Natural Heritage Program or email them to firstname.lastname@example.org.
Don Lyman is a biologist, freelance science journalist, and hospital pharmacist who lives north of Boston. Send your questions about nature and wildlife in the suburbs to email@example.com.