Research “Home Run” with First Protected Terrapin Nest @ Holly Beach

Female Terrapin #272 — First Protected Nest @ Holly Beach

Once in a blue moon comes a turtle, a diamondback terrapin, that provides researchers with such rich material that we describe the event as a home run.  Such a turtle, Terrapin #272, scrambled ashore at a newly discovered nesting site, Holly Beach, on the west coast of Sippican’s Outer Harbor. 

This exquisite female had first been discovered by Turtle Journal in June 2005 at another nesting site.  Today she revealed how well she has done in the intervening seven years.  She hinted that deteriorating conditions at her former nesting beach had pushed her to a new location.  She gave us 12 fresh and viable eggs to study and to protect.  And with a little bit of good fortune, her nesting efforts will yield a clutch of perfect hatchlings in September to examine and to release as new recruits to restore the dwindling population of Sippican terrapins.

Terrapin #272 Covers Nest @ Holly Beach

Don Lewis strolled down the lane at 1 pm to check the newly discovered nesting spot at Holly Beach.  So far this season, after being alerted to the site by concerned residents, Turtle Journal had confirmed more than a dozen depredated nests and had examined three female terrapins at Holly Beach.  See Tracking Elusive Terrapin Yields Important Discovery: Legendary “Bigfoot” of Buzzards Bay and Rescued Terrapin Thrives in New Habitat: “Bumpy” Stretch Behind Her.

As Don approached the beach, he spied a turtle crawling swiftly through the grass.  He dropped behind a boulder and a stand of phragmites to avoid disturbing her.  The terrapin stopped here and there along her journey, she scratched the surface and threw dirt over her shell, and she went on.  At one spot, she thrust her face into the soil, paused for a moment, then moved her powerful back legs over the sand, and began digging in earnest.  Alternating left and right rear limbs, she probed deeply into the ground.  After 15 minutes, she paused again, positioned herself over the hole, and began the laying cycle; deep breathing, dropping eggs and positioning them carefully in the egg chamber.  Once the terrapin began to cover the nest, Don moved closer to film the final moments and to be sure he could find the now camouflaged nest.

Terrapin #272 in 2005 and Terrapin #272 in 2012

We first saw Terrapin #272 on 22 June 2005 on a nesting run at the barrier beach in Aucoot Cove.  She was still gravid (carrying eggs) and weighed 990 grams.  On July 17th of the same year, we saw her again on a nesting run for her second clutch of the year.  She was gravid and weighed 913 grams.  That weight loss is expected from first to second clutch, since a terrapin invests 10% to 15% of her body mass in each set of eggs.

Today, Terrapin #272 was nesting at Holly Beach, which is in the next estuary to Aucoot Cove.  The turtle would have had to swim about a mile around Converse Point or crossed about a quarter mile on land to reach her new nesting site.  Turtle Journal has long noted that nesting conditions on the Aucoot barrier beach were deteriorating due to increased human activity and continuous storm washover.  We had speculated that turtles would be forced to find new nesting areas before long.  Terrapin #272 is the first turtle that we have confirmed taking this predicted course of action.

In the intervening seven years, Terrapin #272 has grown almost a full centimeter in length.  Her new weight, including the egg mass she had just deposited, was close to 1100 grams.

Neighbors Observe Terrapin Nest Excavation

After securing the turtle, Don and interested residents, examined the location that Terrapiin #272 had chosen to dig her nest.  It was a grassy spot that would prove challenging for the eggs to avoid root and other predation.  Since these eggs represent the first viable nest discovered at the new site, Don decided to relocate them to a secure turtle garden where they could incubate in safety  Once hatchlings emerge in September, they will be returned to the nursery salt marsh abutting Holly Beach.

Lisa Holds Terrapin #272′s 12 Perfect Eggs

Resident Lisa Novakoff, whose home overlooks the nesting site, holds the 12 pink and perfect eggs deposited by Terrapin #272 at Holly Beach.  Andretti, a young and inquisitive visitor, watches in amazement.

Terrapin #272′s 12 Eggs Weigh 94 Grams

An element of our research home run is to have access to the eggs of a known female (#272).  We weighed the eggs to determine the overall clutch size (94 grams) to compare to the mother’s size.  There would have been a few additional grams of “water” to add to the egg mass.  Second clutch nests tend to be lighter than the first clutch, because mothers have already invested a large percentage of their body mass in their first set of egg.  There also tends to be one or two fewer eggs in the second clutch.

Individual Egg Weighs 7.4 Grams

Since the nest was being relocated to a safe turtle garden, we had the opportunity to take measurements of each of the eggs.  Later, we will compare these measurements to the eggs just prior to “pipping,” when the babies pierce the eggshell, and with the hatchlings once they emerge.  The eggs ranged from 7.4 grams to 8.6 grams, and from 2.92 to 3.30 centimeters long, and from 1.94 to 2.03 centimeters in diameter.

Eggs Relocated to Safe Turtle Garden for Incubation

To ensure we can stretch a research triple into a home run, we relocated these viable eggs to a secure turtle garden and we capped the nest with a predator excluder.  With a normal Cape Cod summer, we expect to see hatchlings emerge sometime around mid-September.  As the time approaches, we hope Holly Beach residents will join Turtle Journal for a celebratory release party.

Terrapin #272 Jets to Freedom

Examination over; weights and measurements taken; and a job well and successfully done; Terrapin #272 left Holly Beach for Sippican’s Outer Habor.  She raced to water’s edge and sped into the bay as though propelled by jets.  So long, Terrapin #272; see you next year!

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