Posts Tagged ‘egg chamber’

Northeast Diamondback Terrapin Working Group Meets at Wellfleet Bay Wildlife Sanctuary

Saturday, September 27th, 2008

Mass Audubon’s Wellfleet Bay Wildlife Sanctuary hosted the 3rd annual meeting of the Northeast Diamondback Terrapin Working Group on September 27th.  Bob Prescott, sanctuary director, and Don Lewis, the Turtle Guy, welcomed more than 30 participants from New England and New York.  Chuck Landrey coordinated the meeting agenda, and Russ Burke, Hofstra University professor, chaired the meeting.

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Particpants Assemble in Wellfleet Bay Wildlife Sanctuary Auditorium

After registration and coffee, the meeting kicked off at 10:00 am with opening remarks by Chuck Landrey, the northeast regional coordinator, followed by Russ Burke, DTWG chair.  Bob Prescott and Don Lewis welcomed participants to the Wellfleet Bay Wildlife Sanctuary and presented a very brief overview of Cape Cod geography and terrapin populations from the SouthCoast to the Outer Cape.  Russ topped off the opening session with an update on terrapin research activities within Jamaica Bay and the challenges of wildlife conservation within bounds of the 11th largest city in the world.

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Opening Presentations by Chuck Landrey, Russ Burke, Bob Prescott & Don Lewis

As entertaining as these opening presentations were, participants earned a nice break before hearing more research updates by Charlotte Sornborger of Barrington, Rhode Island, and Barbara Brennessel, professor at Wheaton College.  Eric Strauss, research associate professor at Boston College, talked about environmental studies and the ecological field station at Sandy Neck in Barnstable where he and Peter Auger have conducted long-term terrapin research.

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Second Round of Presentations by Charlotte Sornborger, Eric Strauss and Barbara Brennessel

Lunch break offered an opportunity for Sue Wieber Nourse and I to zip over to Lieutenant Island to check for emergence nests.  Three days of pouring rain and the tropical front accompanying Hurricane Kyle presented conditions favorable for late hatching terrapins to emerge through the soften soil.  At the intersection of a one lane dirt road and a driveway on Marsh Road, we discovered an emergence hole with a tiny diamondback terrapin hatchling poking its head out.  Excavating the egg chamber we rescued four live hatchlings and found two premature hatchlings that had been crushed inside the nest by vehicular traffic.

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Saving Turtles for Lunch from a Vulnerable Road Nest

The afternoon session was devoted to an exchange of information and views on a variety of terrapin research issues as enumerated by the following charts.  Topics included headstarting, how do hatchlings know home, list of predatory and beneficial plants, hatchling survival rate, relationship between age and salinity tolerance, unpublished data on diet, terrapins in captivity, legacy data sets, where do hatchlings hang out, starting a basic terrapin conservation program, capture-mark-recapture methods, tracking methods, mating aggregations, nest protector design and temperature, terrapin survey methods, and how do you know what terrapins are doing when not nesting.

Terrapin Research Topics of Interest to Participants

After a very long and productive day, during which Hurricane Kyle had deluged the auditorium windows and walls with rain, the time had come for a soagy field trip.  Participants assembled in the Nature Center and began the trek along Goose Pond Trail to Cape Cod Bay where we would release the female and male terrapins that Sue and I had captured on Wednesday (see The Last Terrapins).  Then, we would walk over to Try Island to check the remaining protected nests and to share an insight into nesting habitat here at the northernmost outpost for diamondback terrapins.

Bob Prescott (with Binoculars) Leads Participants Down Bayside Boardwalk

En route to the bay, we stopped by an exemplar area of salt marsh die-off to talk about this phenomenon on the Outer Cape.  I spotted a large male squareback marsh crab, one of the prime suspects in the die-off, guarding its muddy burrow.  Bob dove into the ooze and bare-handed the critter; a noble feat since we normally use 3-mil plastic gloves for this work due to the ferocious tenacity of these crabs.  Bob showed off his catch to clicks of rain-drenched cameras.

Bob Prescott Shows Large Male Squareback Marsh Crab to Conference Participants

As downpours resumed, we reached a creek leading to the bay and released our turtle guests back into the wild.  Afterwards, we examined the nesting habitat on Try Island and elsewhere along the Goose Pond Trail, arriving back at the Nature Center tired, soaked and completely satisfied with a most informative and fun filled day.

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Hurricane Kyle Field Trip at Wellfleet Bay Wildlife Sanctuary

Confronting Maggot Infestation in Wareham Turtle Garden

Saturday, September 13th, 2008

As we described earlier in the post, “Rescuing Live Hatchlings from Maggot Infested Nests,” fly maggots devastate threatened diamondback terrapin nests on the Outer Cape.  They devour tiny, vulnerable hatchlings as they break their eggshells in the secret darkness of their hidden underground nests.  When we encounter a nest infested with maggots, and after we suppress our disgust and repulsion, we aggressively excavate the egg chamber in order to save as many hatchlings as we can.

Terrapin Egg Completely Consumed by Fly Maggots

This Thursday we checked on a nest laid late last June in a new turtle garden off Broadmarsh River in Wareham, 60 miles from nests on the Outer Cape and on the other side of the Cape Cod Canal.  Still, once we penetrated the egg chamber the sand resembled an Indiana Jones movie scene with maggots playing the role of snakes.  “Maggots,” exclaims the Turtle Guy.  “Why does it have to be maggots?”

Maggots in Motion

We ignore the stench and dig quickly through the slithering sand to rescue eight live hatchlings among the devoured remains of eggs and embryos of seven might-have-been siblings. 

Eight Saved, Seven Depredated by Maggots

The rescued hatchlings appeared lethargic as though traumatized by the experience.  But after an overnight stay in clean, moist soil, and a leisurely bath in warm fresh water, they were eager for release into the wild.  That is, turtle eager which isn’t quite the same thing as mammal eager.

Hatchling Strolls through Wareham Turtle Garden

The background of the previous video clip shows the exquisite nesting habitat that was created by private homeowners abutting the nursery salt marsh of Wareham’s Broadmarsh River off Buzzards Bay.  At their own initiative and their own expense, the homeowners petitioned the Town of Wareham Conservation Commission for permission to create a perfect nesting habitat along a beach front that had become sand starved over the years and had lost all upland nesting potential.  These generous homeowners ordered 20 tons of perfectly matched beach sand to make a large nesting site at least 10 inches deep for terrapins to place their clutches.  Within a couple of weeks of completing this turtle garden, the first female terrapin had scratched and dug her nest.  In total, six nests were deposited in the new sandy turtle garden … all of which were protected by predator excluders.  As these new babies mature, they too will return to this turtle garden, ensuring a whole new generation of diamondback terrapins in Broadmarsh River; all thanks to an exceptional family who are dedicated to restoring the Wareham coastal ecosystem for future generations.

Two-Ton Vehicle Versus Quarter Ounce Hatchling

Sunday, September 7th, 2008

Due to human development and associated pressures, some of the best remaining nesting sites for diamondback terrapins on the Outer Cape are one-lane dirt roads that abut salt marsh nursery ecosystems for hatchlings. Obviously, roadways are extremely dangerous for the female as she spends more than 30 minutes digging her nest, depositing her eggs and covering it once again.  Because these compacted roadways are so hard, and her nest sculpting creates a natural arch to spread the load of vehicular traffic, the eggs appear to do fine through June, July and August as they incubate under the summer sun.

Female Terrapin Nesting in Middle of Dirt Road

But when hatchlings begin to pip and squirm about in the nest, and when one or more begins to tunnel to the surface leaving an emergence hole in the road, then the architectural integrity that served so well during incubation is compromised.  Weight no longer is evenly distributed, and the egg chamber compresses and begins to collapse under the stress. 

Emergence Hole in Middle of Marsh Road on Lieutenant Island

I discovered this little (3 gram) hatchling wedged under the lip of the nest that had been collapsing under the day’s traffic.  Two of its siblings had already been crushed in the center of the egg chamber.

Premie Hatchling Distorted by Road Traffic

In addition to problems with its distorted shape, its eggshell had been invaded by fly maggots that were trying to find a vulnerable orifice to invade.  I had to hand-pick these nasty predators from the tiny hatchling.  Based on experience, I know that this critter will now do quite well.  With a little time, some warm hydration and a bit of TLC, its shell will resume a normal shape and it should be ready to be released into the wild within a few days to a week.

Emerged Terrapin Hatchling Run Over on Marsh Road

I wish the same could be said for another sibling (above) that I found a foot outside the nest and squished in the south tire track of the dirt road.  It’s a dangerous world for a turtle hatchling.  Few survive to tell the tale of their harrowing youth.  But with a little luck and a guardian angel or two, one turtle at a time can be saved and the whole world along with it.

Close-Up of Rescued Distorted Hatchling

Peek Inside the Egg Chamber

Tuesday, September 2nd, 2008

Like a clenched fist deep inside a carefully carved terrapin nest lies the egg chamber where the female has deposited her clutch 75 days earlier. When the clock chimes “emergence,” hatchlings squirm and wiggle their way free of their siblings to begin their dash for survival.  Today at noon the alarm rang for Nest 280 on the high dune of Turtle Point on Lieutenant Island.  Count noses, count eyes, count limbs as hatchlings get ready to sprint for freedom.

Hatchling Bunched Tightly in Egg Chamber