Posts Tagged ‘diamondback terrapin nests’

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.

Rescuing Live Hatchlings from Maggot Infested Nests

Wednesday, September 10th, 2008

No, it’s not a pretty thought.  It’s not a pretty sight and it’s certainly not a pleasant experience.  But it is the real world of terrapin conservation and so for the serious naturalist, it’s a necessary learning moment.  Be thankful that the pictures are two dimensional and that there is no smell-vision key on the video clip.

Research from September 2000 revealed for the first time that a significant percentage of diamondback terrapins nests in the Wellfleet Bay system were being destroyed  by fly maggots.  The infestation appears to begin at pipping when hatchlings poke openings in their eggshells allowing the odor of organic material to escape and to attract flies.  Since Outer Cape hatchlings remain in their shells and underground for several days after pipping, maggots have the opportunity to attack an extremely vulnerable prey as the maggots work their way through the cracked shell to devour the exposed hatchling.

Pipped and Vulnerable (Upside-Down) Terrapin Hatchling

In most cases, the maggots begin with the umbilicus and enter the main body of the living hatchling through the yolk sac, hollowing out the baby from within.  Thus, hatchlings and whole nests are destroyed by these insidious predators underground without ever being exposed for counting by researchers like nests preyed upon by more obvious predators.

Maggots Attacking Helpless Hatchling (Rescued)

Observations over the last nine seasons confirm the 2000 discovery and underscore the severe constraint this predation places on the number of live hatchlings that emerge on the Outer Cape each year.  This season (2008) alone has seen more than half of all nests in the critical habitat of Lieutenant Island infested with maggots.

Maggots Consume Hatchling Embryo

Thankfully, the aggressive conservation protocols developed after the 2000 discovery have rescued more and more hatchlings each year from this infestation.  By checking nests as they begin to pip and harvesting them at the first sign of maggots, our efforts have significantly increased the number of live hatchlings entering the system since the turn of the millennium.  Even after the infestation has begun, our actions can save most hatchlings from the most heavily infested nests.  We harvest the pipped eggs and remove all maggots before re-burying premature hatchlings in clean, moist soil to finalize the incubation process.  These efforts have rescued thousands of hatchlings that would never have seen the light of day.

Hatchlings Rescued from Maggot Infested Nest

This particular nest on Turtle Point gave away its location by a concavity on the surface.  As hatchlings pip and squirm around inside the egg chamber, sand gets displaced and this underground activity shows itself as ripples of the surface sand to the most seasoned turtle researcher.  We were able to rescue 10 baby hatchlings from the devouring horde of maggots in this nest, hand-picking tiny maggots from limb cavities and off yolk sacs, then bathing the hatchlings in clean, fresh water for rehydration before release.  So, a good day in the Land of Ooze where we saved an order of magnitude better than our goal of one turtle at a time.