Turtle Journal

South Lieutenant Island presents diamondback terrapins with a Hobson’s choice: marginal nesting sites surrounded by the best developmental habitat in Wellfleet Bay.  Except for a single isolated sandy face where predation rates soar to over 90%, the south side of the island is ringed by a narrow strip, sometimes only inches wide, of soil and mixed vegetation between the high tide wrack line and a dense bearberry groundcover.  Turtles can opt for the more appealing dirt roads and driveways, but at the risk of encountering a host of predators, wild and mechanical, en route upland.  And the trek back to the nursery marsh for hatchlings would be doubly dangerous.

 Marginal Terrapin Nesting Site North of Round Island

Two nests, indicated by red turtles on the orthographic map above, illustrate this dilemma.  Only 50 feet apart, these turtles choose equally borderline nesting locations.  The one on the left found a small scratch of soil (top center of photo) beneath a beach plum bush; the one of the right picked a location (dark spot 2/3s up & center right) sprinkled with grass and weeds.

Marginal Terrapin Nesting Site North of Round Island 

Although riddled with roots, the left nest still yielded 14 live and emerged hatchlings.  The other, though, was invaded by vegetation which penetrated the eggs and killed the pipped hatchlings.  The only difference I could detect was that the soil in the first, productive nest felt moist to the touch; the second was bone dry — even after a soaking rain and fog.

Egg Shards Near Marginal Terrapin Nests

Despite these hurdles, the overwhelming advantage of its abutting pristine marsh has made Lieutenant Island the most productive terrapin hatchery in Wellfleet Bay.

 Fog Enshrouded Pilgrims Monument in Provincetown

Fog rolled in thick enough to ooze puddles along Cape roadways and to shroud Provincetown’s Pilgrim Monument in London-esque mystery.  A perfect day for a detective story, especially one with a surprise happy ending.  Into this dense veil walked an alert couple just after noon.

Couple Discover Tiny Terrapin Hatchling at Crosby Beach

They chose Crosby Beach in Brewster and strolled its rolling sands toward the mouth of Namskaket Creek.   On the beach (at the spot marked with the red turtle), they detected a most unusual sight: an inch-long crawling pebble.

Six Gram Diamondback Terrapin Hatchling

Knowing they found something extraordinary, they called the Wellfleet Bay Wildlife Sanctuary for an identification.  To confirm its ID, the couple was asked to bring the specimen to the Nature Center for an expert examination.  Sure enough, they had discovered a 2.68 centimeter long, 6 gram diamondback terrapin hatchling.

While we suspected from the quality of the marsh and the surrounding uplands that terrapins may be present in Namskaket Creek, we have never been able to confirm that suspicion.  On 30 March 2000, the remains of a 9-year-old female was discovered on nearby Linnell Landing, sparking our interest again in Namskaket.  But it could have washed up from anywhere along the bayside coast in a spring storm.  We needed a live sighting to confirm our surmise.

Today, Hatchling 011-01 provides that evidence.  We’ve alerted the Cape Cod Nature Network of this find and asked folks to be alert to nesting females on surrounding uplands (dunes, wrack lines, dirt roads and driveways), beginning next week and until around 20 July.  We’ll launch a sweep of these same uplands during and after the nesting season in search of terrapin signs.

Namskaket lies midway between the large population in Barnstable Harbor and the northernmost population in Wellfleet Bay.  A new breeding population in Namskaket Creek would be an important discovery for Cape Cod’s diamondback terrapins.

Kayaking in Blackfish Creek at Mid Tide

If anyone asks whether you’d prefer to be good or lucky, pick lucky.  Good only describes process, while luck produces results.  Today proved another case in point.

Midway through a lunar cycle means tides are not workable for locating and netting turtles in Blackfish Creek.  We pulled up stakes for a few days until things improve as the full moon approaches.  A wayward jet stream has blown constant winds and white caps across the bay reducing water visibility to zero.  So, I took the day off from research to introduce a house guest to the joys of kayaking.

As luck would have it, we arrived at the shore a couple of hours before low tide.  I outfitted my companions with life vests, shoehorned them into kayaks, handed them paddles, and shoved them off into Wellfleet Bay — leaving me to my own devices with nothing productive to do.

 Male Terrapin #1081 and Female Terrapin #785

As luck would have it, I had advertently (!) brought along a net — just in case.  I kayaked across to the flooded rip, jumped out, and waded hip deep in water with the boat lashed to my life vest.  For just a few moments, the wind dropped to near calm and the murk parted enough to see shadows as the tide ebbed.

And, as luck would have it, two turtles tried to swim the rapids just in front of me.

Terrapin 785 is a beautiful pre-pubescent female about 8 years old.  I first saw her on 29 July 1999 when she was only 13.3 centimeters long and 408 grams in weight.  Since then she has grown nearly 1.5 centimeters and 150 grams as she nudges the puberty threshold. I suspect next year (2002) will mark her first nesting season.  The second turtle was marked 1081.  He is a 7-year-old, mature male at nearly 11.9 centimeters length and 283 grams.  He showed muddy residue in his frontal cavity and along the rear, while #785 was clean of all vestiges of brumation.  She did, however, have a ring of light green seaweed clinging to her rear marginals.

Don Lewis Examine Male Diamondback Terrapin

One interesting observation:  In July 1999, I had noted a pimple-like growth in Terrapin 785’s mouth.  Today it was clear — as luck would have it.