The Story of Nest 28 4 September 2001
Today the last hatchlings emerged from Nest 28, completing a cycle that began 81 days ago. With the final chapter written, it seems a perfect opportunity to review the whole story and perhaps gain a keener insight into the nesting process at the northern edge of terrapin habitat.
Five days into the season on 15 June, we were just entering the crest of the first nesting wave. Wellfleet turtles generally deposit two clutches annually, separated by about two weeks. The first clutch usually peaks around 23 June, but this year nesting crested from the 16th through the 18th, about a week earlier probably due the temperature spike we experienced during the last ten days of April.
So, on the evening of the 15th, Terrapin 338 was found by Keeper and me (see A Little Help from Friends 15 June) as we patrolled Lieutenant Islands Turtle Point for nesting turtles.
Our observational history with #338 stretches back to the morning of 26 June 1993 as she made a nesting run on Turtle Point. At the time, we estimated her age at 12 years. She measured only 16.5 centimeters and weighed a mere 700 grams, both of which indicated she had recently passed the nesting maturity threshold for Wellfleet turtles, probably the previous year.
She wasnt seen again until 15 June 1999 on another nesting run at Turtle Point. By then she had added a centimeter in length and 250 grams in weight. Now, two years later, Terrapin #338 measures 17.8 centimeters and hits the scales at over a 1000 grams AFTER she laid her clutch.
The nest was fairly easy to discover as I spotted an area of unnatural smoothness in the dune sand. Gently brushing back the top layer of soil, I confirmed a viable egg chamber (below left).
I re-covered the nest, temporarily secured it with a few fist-size rocks and some drift wood (below right), and field marked it with human scent to ward off predators until I could return in the morning with an excluder cage. Luckily all went according to plan and Nest 28 remained undisturbed through the summer.
On 31 August Dr. Burt Jaffe, an honored graduate of our summer field school (see Terrapin Field School Wraps Up 29 June), returned to the Land of Ooze to see the rest of the story. At the end of a successful morning discovering hatched nests and emerging hatchlings, we revisited Nest 028 for a check. To our surprise we found a fly motionless, sitting atop the center of the egg chamber. We decided to investigate. We lifted the cage and gently hand-brushed sand from the nest. We were curious to learn what had drawn the fly to the nest, AND I was interested in scooping away any eggs that the fly may have laid. When we reached the nest, we found a non-viable egg on top. Removing it, we discovered the next egg had slightly pipped with just enough room for a limb to protrude through the crack. We quickly re-covered the nest with fresh sand and replaced the predator excluder. Later, on the walk back to the jeep, we argued about whether the fly had been attracted by scent once the integrity of an egg had been breached or by the sound of pipping. Burt, as an eye/ear/nose specialist, took both sides and won each point in turn.
No activity occurred at Nest 28 until yesterday, 3 September, when we found Hatchling 157 striking a James Cagney pose at the bars of the predator cage. At 2.41 centimeters and 5 grams, she seemed awfully small to be the first baby to emerge. Once again we checked the egg chamber to be sure no maggots had hatched from the earlier fly visit. We found none, but again noted that the top two eggs were slightly pipped with only a single limb exposed. We re-sealed the nest.
Nothing more happened last evening, but first light this morning brought five more hatchlings topside in the cage. This time an excavation yielded six more hatchlings in the egg chamber waiting for their chance at freedom. Only one needed a little help. Hatchling 182s egg had dried and hardened around his shell. But it was brittle enough to pick off with my fingernails. Once I had measured and weighed all the babies, I understood why the first one was so small. They were all VERY small, averaging about 2.5 centimeters and only 4 grams with the smallest barely registering 3 grams on the scale.
The final count for Nest 028: 12 live hatchlings and 2 non-viable eggs. Todays batch of eleven showed all the razzle-dazzle of a football team as they scrambled for freedom on release. After a few minutes of drunkards walk, zigzagging this way and that along the base of the dune, they got their bearings and headed to the marsh, disappearing into and under the thick mat of wrack.