Turtle Journal

Canine Depredated and Desiccated Over-Wintered Terrapin Nest

Drought has real consequences on wildlife, and this morning I discovered its brutal effect on 33 over-wintering terrapin hatchlings.  The Cape has been precipitation poor for several months, and while residents have been blessed with pleasant sunshine, the ground has become exceedingly parched.  You may recall on Friday we discovered a live, but seriously dehydrated hatchling in a coyote predated nest on Lieutenant Island’s Turtle Point — along with several desiccated hatchling remains.  So, today we patrolled another section of the south Lieutenant Island marsh to see if there were any other exposed nest sites.

We found three within a 20-foot sandy stretch between the wrack line and an abutting bearberry hill.  In each case, the predator had dug until it reached the first desiccated remains, then broke off the predation and left the rest of the nest chamber intact.

Second Desiccated Over-Wintered Terrapin Nest

As I excavated below the exposed egg, I discovered over-wintering hatchlings which had pipped, but remained inside their shells.  The first nest contained 8 dead, the second had 13 remains and 2 non-viable eggs, and the third held 12 desiccated hatchlings.  None had been disturbed by the predator once the initial dried-out turtle was encountered.

Third Desiccated Over-Wintered Terrapin Nest

Hatchlings were normal in every way, and the condition of the nest chamber, the eggs and the babies precisely matched the pipped babies we rescued in the fall — with one fatal difference.  These were all completely dehydrated, presumably caused by the spring’s lack of precipitation.  Today’s discovery coupled with Friday’s may prompt us to rethink our fall nest strategy.  We had become more aggressive in recovering pipped hatchlings once we found pervasive fly maggot predation last year.  We’ll now need to weigh the pros and cons of over-wintering nests.  True, we lost these nests to drought conditions.  But it seems likely that had not the drought intervened, these hatchlings would have been consumed by predators.

Release of Over-Wintered Hatchling Rescued from Coyote Predation

The morning broke warm and bright with a southwest breeze bathing the Cape in our first wave of summer humidity.  In other words, a perfect day to release Hatchling 001, dubbed Ott, who was rescued from the coyote track yesterday.  Overnight she first soaked in fresh water, and then ambled about her terrarium and burrowed into brackish mud.  Within those few hours she had rehydrated and double her weight to over 6 grams.  And she was a lot more alert and active, too.

Hatchling Disappears under Wrack Line

Released in the wrack at Turtle Point, she crawled over to the cover of a sea lavender and soon disappeared beneath the marsh hay.  Bon chance!

Mature Female Terrapin #363 Swims through the Rip

In Blackfish Creek the tides have swung into mid-phase mediocrity — not very good for turtle observations.  But on the off chance, I dragged the dinghy onto the rip and scanned the channel for passing terrapins.  As the tide reached dead low, a mature female appeared in the rapid.

Terrapin 363 has been under observation by our researchers since June 1996 when she was first discovered during a nesting run on Lieutenant Island.  Then she measured 17 centimeters long and weighed 920 grams.  Three years later and twice last year, #363 was found nesting on Lieutenant Island.  Today was the first time she had been seen in Blackfish Creek.  She now stretches 17.5 centimeters and hits the scales at 1024 grams — over 200 grams (!!!) larger than her weight on 29 June 2000 just after she had laid 14 viable eggs in a Lieutenant Island driveway.

Female Terrapin #363 Meets Mothers’ Day Visitors

With Mothers’ Day Weekend in full swing, there were many beachside visitors this morning, all of whom had the opportunity to meet Terrapin 363 and to hear about diamondback terrapins and Wellfleet Bay’s research and conservancy program to protect this threatened species.

Luck played its trump card today.  In Blackfish Creek, clear skies and clearer visibility allowed us to net a lucky seven terrapins in this morning’s low tide, none of whom had ever been observed before.  And, in the best luck of all, an unplanned visit to Turtle Point afforded us the chance to save a baby hatchling which had been dug out of its over-wintering nest by a scavenging coyote.  Two thumbs up for Friday 11 May.

Steve Smith, Curator of New Bedford’s Buttonwood Park Zoo in 2001

Steve Smith, curator of the Buttonwood Park Zoo in New Bedford, Massachusetts joined me at 0730 to sample the pleasures and excitement of terrapin research in the Land of Ooze.  We were blessed by sunrise temperatures in the low 60s, water temperature also in the low 60s, and a light refreshing 5 knot breeze out of the northwest.

Mature Female Terrapin Paddles through Low Tide Rip

Everything combined for a great outing with fairly good visibility as terrapins streamed through the rip.  Steve netted the first turtle (#1064), a 12-year-old female of 18.55 centimeters length and weighing over 1100 grams.  We traded captures for the next hour with the final tally equaling four females and three males, none of which had previously been seen.

Mature Female Terrapin with Exposed Bone from Traumatic Injury

As the tide ebbed, a terrapin pair nearly slipped by.  The male, covered in light green algae, hit the scales at 240 grams; the female over a 1000 grams.  She had sustained a severe injury to her left side some time ago, as it was well healed.  Bone was exposed along the marginal from mid-point on the left side to the rear quadrant.  The trailing edge of her left rear foot was also affected.

Tiny Over-Wintered Terrapin Hatchling in Coyote Paw Print

As we left the beach, we decided on the spur of the moment to visit the nesting areas and nursery marsh around Turtle Point — even though it’s a month shy of the season — to give Steve a sense of what the habitat looks and feels like.  As we rounded the hill, I mentioned that a coyote had been frequenting this area and digging in the dunes where nests had been laid and hatched last year.  I pointed to a newly excavated spot with the paw print of a coyote still clearly visible in the sand, and then my mouth dropped to the ground.  Hunkered in the shade of this paw print was a terrapin hatchling!  We both thought the worst, because it didn’t move and its eyes seemed shut for good.  But as Steve held the baby in his palm, it began to stretch its neck and legs.

First (Over-Wintered) Hatchling of 2001 from Coyote Depredated Nest

Excavating beneath the coyote print, I discovered 5 non-viable eggs remaining in the nest chamber, 1 deformed dead hatchling which had pipped, and 6 shells from which turtles had emerged.  As we left the site, we discovered another hatchling which had expired along the pathway.  Both this one and the live one we recovered were extremely dehydrated and weighed less than 4 grams.  The surviving turtle measured 2.7 centimeters long and 2.35 centimeters wide.  She sported a desiccated yolk sac on her plastron.  Had we not happened across this secluded spot and peered closely into the paw print, this hatchling would not have made it through the day.

Over-Wintered Hatchling Rescued from Coyote Depredation

Back at Connemara Cottage, I immersed Hatchling 001-01 (named Ott) in fresh water and placed her overnight in a moist, sandy terrarium.  As soon as conditions allow, she’ll be released into the nursery marsh off Turtle Point.

Last night, spring threw us one final curve with temperatures probing the upper 30s.  As I left for the creek this morning, the thermometer read 41 degrees.  Luckily the wind had dropped to a mere 5 knots out of the north.  In other words, it was a delightful day for wading in the rip even though the number of terrapins alert and moving with the tide is still fairly limited.  And none were snorkeling for air as they swept through the rapids.  Instead, they hunkered along the bottom where water temperatures were more terrapin friendly.

Female Terrapin #1006 About to be Netted

Turtle 1006 paddled through about 90 minutes before ebb tide.  She’s a mature female whom we last saw just five days ago as she ran the murky rapids on Cinquo de Mayo.  Since then she’s dropped 18 grams in weight.

Mature Male #1061 (Left), Prepubescent Female #1063 (Right)

The next two captures, #1061 and #1063, proved extremely interesting and instructive.  Terrapin 1061 is a sexually mature 7-year-old male; Terrapin 1063 is a pre-pubescent 5-year-old female.  They were both the identical length, 11.2 centimeters, and nearly the same weight, 250 grams.  And they pose one of the more difficult challenges for the amateur field researcher: distinguishing gender differences between a mature male and a young female before puberty, that is, before obvious size dimorphism kicks in.

From the topside, you can detect the rounder, plumper form of the juvenile female (#1063 on the right) than the shallower-shelled male (#1061 on the left).

Prepubescent Female #1063 (Left), Mature Male #1061 (Right)

Looking at the bottom, the thicker male tail of #1061 on the right can be compared with the thinner female tail of #1063 on the left.  Note also the relatively longer plastron length of the female on the left (87.5% of carapace length) to the male plastron on the right (less than 82% of carapace length).

Captured together, they provide a great visual lesson for terrapin field researchers.

 Terrapin “Exercises” in Field Office

Finally, in response to several reader concerns, we have installed an OSHA-certified ballet bar in the dinghy, so that terrapins in the processing queue can keep in top form while waiting for release.

Terrapin Makes a Quick Exit after Processing

And you’ll be pleased to note that this stretching exercise seemed to have had immediate positive results.  Kick, stroke, kick, stroke.

Unbelievable!  The thermometer outside Connemara Cottage read 30 degrees when I left for the dawn low tide.  Not only was the marsh laced with frost, but ice had to be scraped off the windshield.  Water temperature over the tidal flats dropped to 50°F — not a turtle friendly reading at all.

Panoramo of Low Tide Drained Blackfish Creek at Sunrise

The wind was dead calm creating an ironing-board flat sea state.  Anything moving through the rip left a telltale wake — anything.  And once the sun rose over Old Wharf Point, water visibility became perfect.  Horseshoe crab pairs by the dozens flowed through the channel, each leaving an identifying wake.  So, with some confidence, I can assert that no critter with the mass of a female terrapin passed through the rip during this tide.  It would have been impossible to slip through without detection.  Although slightly less assured, I think that few, if any, smaller male turtles moved through the channel.

Freezing Male Diamondback Terrapin #907

The tide ebbed at 0613 and with nothing but horseshoe crabs stirring, I packed up my gear and prepared to wade back across the creek when I spotted two smallish wakes approaching the first drop.  Well, what could it hurt to check it out?  The first proved a spider crab edging its way over the rip.  The second, though, showed a raised keel and, sure enough, here came Terrapin 907.  He plopped over the rapids and drifted into my left hand.  Cold to the touch, he was very sluggish, withdrawn as far as he could inside his shell.

One of the few “mustached” terrapins, #907 measures almost 12 centimeters long and weighs nearly 300 grams.  He was last spotted on 5 August last year swimming the morning tide through the rapids.  On release today, he basked for a goodly time in the morning sun before stretching his neck and ambling off back into the chilly creek.  I’ll wager he wish he had “put on” one more blanket of ooze before drifting off to sleep last night.

The Real Survivors

Four Terrapins Captured on Afternoon Low Tide

Bright sunshine warmed water temperatures in Blackfish Creek to 62 degrees by the afternoon tide, and lots of turtles were on the move.  A stiff southwesterly breeze replaced its northerly counterpart, yet still managed to kick up enough turbulence to obscure visibility.  Despite those adverse conditions, four terrapins were captured on the evening low.  Three were first timers and one was a repeat from last July 29th.  Two were males and two were females.

 Male Terrapin #1060 with Exposed Bone in Left Forelimb

The most interesting captures were #1060 and #1070, both of whom well represent my slogan for these extraordinary animals, “The Timex critters — They take a lickin’ and keep on tickin’.”  Terrapin 1060 was the first captured of the evening as he paddled through the rapids.  My attention was attracted by a shiny brightness where the sun reflected off an exposed bone on his left forelimb.  The wound looked somewhat fresh, as the joint had not yet been covered.  Number 1060 is the largest confirmed Wellfleet Bay male with a 13.7 centimeter carapace length and 370 grams weight. 

Female Terrapin #1070 with Traumatic Injuries to Left Side

Fifteen minutes later Terrapin 1070 was netted.  She is a 9-year-old mature terrapin who suffered a traumatic encounter in her distant past.  A large chunk of marginals on the left side and left rear foot are missing.  Despite this well-healed injury, #1070 at 17.5 centimeters and 928 grams is a well-nourished and perfectly normal pubescent female.

On release, both ambled back to the creek and resumed a happy, healthy turtle life.  Now, these specimens are what I call real survivors, as opposed to Tinsel Town stand-ins.