Published on July 13, 2022

Diamondback Terrapin Nesting Season: the Half-Time Report

Heather Pilchard and Tina Maloney with females_Meredith Harris_resized
© Meredith Harris

As the Outer Cape’s Diamondback Terrapins conclude their nesting, our Wellfleet Bay terrapin team is enjoying a bit of a breather and assessing how the season is shaping up.

As always, it’s been busy with 85 volunteers and staff twice a day checking sites from Orleans to North Wellfleet for nests and protecting them from predators. Diamondback Terrapins are a threatened species in Massachusetts due to habitat loss and, over a century ago, excessive harvesting.

A New Take on Nest Protection

This year the team has expanded the trial of a new type of predator excluder(PE)—a self-release PE first tested by volunteers Bill Allan and Barbara Brennessel. Unlike the traditional PEs, the cages that require digging a 10-inch trench around a nest before they’re installed, the self-release PEs are flat pieces of wire that are simply placed and secured over the top of a nest. When hatchlings emerge from the ground, they can exit the PE and seek cover rather than wait inside a cage for release. Game cameras are being installed to determine whether the self-release PEs work as intended.

Predators Finding Nests First

Teams regularly reported predators digging up nests before the nests could be protected. Raccoon tracks were more prevalent this year at several Wellfleet nesting sites, especially Lieutenant Island, which has had more than twice the number of depredated nests over last year. Another leading suspect? Red foxes. As Barbara Brennessel noted in one report, “I think the only way we are going to protect nests at Indian Neck is if we see the turtle nesting.”

Crazy Shifts, Calamities, and Curiosities

Black terrapin_Bill Allan-resized

Each field season brings its accounts of explosive bouts of nesting— 15 nests were found during just one shift, turtles were reported in homeowners' yards (at one Wellfleet home eight terrapins nested at the same time!), and, sadly, too many turtles (nine this year) were run over and killed, some of them older, productive females.

There’s a least one nest we hope to hear more about later this summer: Bill Allan found an unusual black terrapin that ended up in someone’s saltwater swimming pool! The terrapin was rescued and later brought to Eastham’s Terrapin Cove conservation area where she nested. Now we’re curious to see what her offspring look like!


Want to help protect and monitor Diamondback Terrapins? We’re still looking for additional volunteers for the upcoming hatchling phase of the season. If you’re interested, please contact terrapin team leader, Jess Ciarcia.

Photo of black terrapin, courtesy of Bill Allan.

2022 Protected & Monitored Nests  
Wellfleet Bay 72
Lieutenant Island 112
North Wellfleet 50
Eastham 196
Henson's Way, Orleans 11
Nauset Beach 4