Citizen Scientist’s Backyard a Hotspot for Colorful Turtles
In the summer of 2016, West Ashley resident Dale Aren reported 28 diamondback terrapin sightings to the South Carolina Department of Natural Resources. The most surprising part? Every one of the sightings was in her backyard.
That’s an unusually high number of turtle sightings, especially in a residential yard. Aren recorded each encounter on SCDNR’s online report form for sightings of diamondback terrapins. The report launched in April of 2016 in an effort to understand where these terrapins are living, moving, and nesting.
The benefit of public sightings, SCDNR biologist Mike Arendt said, is that “public input helps us get a better sense of the overall distribution of diamondback terrapins in South Carolina so that we can make sure we’re conducting research in the right areas.”
For Food and the Finer Things
Diamondback terrapins almost became extinct in the 19th and 20th century due to over hunting for their shells and meat. Now the terrapins are listed under South Carolina’s State Wildlife Action Plan as a “high priority species” for conservation and have since gained protection from commercial harvesting.
Terrapins are turtles that live on land and in brackish water (semi-salty water found in estuaries). They hang around in the marshes feeding on critters and vegetation. Terrapins are instrumental in curbing the marsh periwinkle snail population, which when out of control can feed on more than their fair share of marsh grass.
The high number of terrapin sightings in Aren’s backyard quickly caught the attention of biologists at SCDNR. Because so little is known about terrapin nesting habits, biologists jumped on the opportunity to collect more data with Aren’s help. By the following breeding season, SCDNR biologist Jeffrey Schwenter had trained Aren to weigh, measure, and tag the terrapins that she found in her yard.
In the summer of 2017, Aren reported 18 terrapin sightings in her backyard, 10 less than the year prior. SCDNR biologists found that the 18 sightings represented 9 different terrapins. Six were only spotted once, while the other 3 were repeat visitors.
“It has been so amazing to me that the diamondback terrapins that come to my garden are the same from year to year,” Aren said. “I look forward to seeing the first visitors in May, scanning them, and seeing they are ‘recaptures.’ Also, some of them come lay eggs 2 to 3 times over the course of the season. They are very particular about their nesting site. I sometimes track them all around the front and back garden for two hours before they find the right spot to dig their nest.”
Terrapins in South Carolina were typically thought to only lay one clutch of eggs per season, but this information reveals they may be laying multiple clutches a season and in the same location.
Creatures of Habit
The 2019 terrapin nesting season has just begun, and Aren has already spotted a familiar terrapin in her yard. This terrapin, DA0-06, has returned to her backyard for three consecutive years. She was first tagged in May of 2017, spotted again in June of 2018, and now has appeared once again at the start of this season.
Excited to see the terrapin again, Aren let SCDNR biologists know of her “repeat customer.”
By returning a third season in a row, biologists can begin to assume that terrapins may have favorite nesting spots that they return to. Aren is on the lookout for DA006 to come back soon to lay her eggs, as she did not dig a nest upon her first visit to the yard.
“I’ve come to think of them as ‘my’ terrapins. I scan, weigh and measure them, record the data, take photos, report online and protect the nests from predators with screening,” Aren said. “I recruit my neighbors to look for them on their property and call me to add them to our database.”
Even if you don’t live near the marsh, you can help SCDNR biologists continue to learn more about the habits of terrapins. If you spot a terrapin or a terrapin nest near the road, in the marsh, or even in your backyard, fill out the online survey with as much information as possible to help scientists better understand the movement and nesting habits of these turtles.