Turtlespotting.

Or should I say crocspotting?

I spent two weeks volunteering on a turtle monitoring project through Conservation Volunteers Australia on the Cobourg Peninsula in the Garig Gunak Barlu National Park.  This very remote location is part of Arnhem Land (birthplace of the didgeridoo), an indigenous area in the northern part of the Northern Territory.  Permits are required to travel in Arnhem Land; even with a permit, balanda (white people) are limited to the specific purpose of their visit and only certain roads of the region.  Anticipating the poor conditions of the 4WD access roads, visitors to the park are allowed only during the Dry season (May to October).  Of course, once you see this beautiful area, you cannot blame them for making it difficult to get there. 

I don’t have a lot of items on my bucket list, but witnessing sea turtle activity is one of them.  I would love to see sea turtles nesting (the females emerging from the ocean waters, dragging their heavy bodies up the beach, and delicately building their nests and laying their eggs before retreating back to the water) and little hatchlings climbing out of the sand and racing for the sea.  I want to experience those magical moments. 

The objective of our 7-person team (2 research assistants, 2 emerging research assistants, and 3 volunteers) was to collect scientific data on the green turtles nesting on Smith Beach.  Each night, we split into 2 teams to patrol the 3.5 km beach (up and back) in 2-3 hour patrols.  If the second patrol was scheduled to finish before 5 am, the early patrol team would also complete a morning survey patrol (one direction) at dusk looking for evidence of anything we missed in the dark. 

Green turtles come ashore at night around high tide to reduce the distance they need to crawl along the beach.  It is laboring to move along the sand; they usually take rests after every 3 flipper movements, leaving recognizable tracks behind in the sand.  Once she finds a suitable location above the high tide line, she begins digging a body pit and then carefully scooping out a nest chamber.  Should she be spooked during this time or feel that something is off, she may abandon her nest and return to the water – this is known as a false crawl.  However, if she does lay her clutch of eggs (green turtles may lay ~100 eggs in a single clutch), she enters a trance-like state.  At that time, the researchers can approach the turtle from behind and count the eggs as she lays them.  Then, we would back away and give her space to cover up and camouflage the nest.  On her return to the water, we would temporarily stop and restrain the turtle to collect information on her, including measurements and a DNA sample.  If she didn't already have flipper tags, the research assistant would attach one to each of her front flippers.  We would also use a GPS to note the coordinates of the nest.

Sounds straight-forward, right?  Unfortunately, there was no opportunity to witness our team in action and no chance to lay behind a turtle and count the eggs as she drops them into the nest chamber.  Over 14 nights of patrolling the beach, we didn't see a single adult turtle.  Nor was there any evidence (tracks) that we had missed a nesting turtle.  During our fortnight, we celebrated a birthday, saw many shooting stars, and watched the turtle constellation move across the sky – and yet, the turtles did not heed our wishes and come ashore.  We even carved turtles into a watermelon for our Halloween jack-o’-lantern.  The main research assistant said he had a volunteer project where the group didn't see a single turtle.  That’s not the record first I was hoping to set.

On the other hand, we did see a bunch of crocs.  On 9 of my 14 night patrols, we saw at least one croc.  We maintained a distance of at least 6 meters from the water line while walking, which often meant that we were marching through the soft sands.  Our only weapon?  A spotlight.  We did not use the spotlight continuously, because it might push turtles into a false crawl.  Every minute or so, we would scan the water and upcoming section of the beach with the spotlight.  Thank goodness crocs have eyeshine.  We would be able to spot the reflected red or white light from the eyes of crocs far ahead.  Then we could safely move around the croc and avoid any surprise encounters.  At one end of the beach is a popular croc crossing area between the beach and a nearby lagoon.  Here lives the legend of Stumpy, a gigantic croc with a deformed back leg which leaves distinctive tracks.  We didn't run into Stumpy nor the giant croc that left these tracks on another beach (check out that huge body slide).

One pleasant surprise for this trip was that we did see three hatchlings.  On our first patrol, we noted hatchling tracks heading from a nest to the water.  We keep an eye on this nest and when we didn't see any new hatchling tracks for a couple of days, we exhumed the nest.  Nest exhumations are important to determine the hatch success rate (we count the shells and any unhatched eggs) and to understand why any eggs may not have hatched (there are different signs based on the predator).  When the hatchlings break out of their eggs, they climb through the sand and wait/rest about 15 cm below the surface.  They are still in a sleepy sort of state and are closing up their belly button.  Somehow, they know when it’s nighttime (temperature change?), and they will emerge from the sand, open their eyes for the first time, and race for the sea.  If we came across evidence that the eggs were still hatching while exhuming the nest, we would have abandoned the exhumation, restore the nest, and wait a few more days for the hatchlings.  As we carefully dug down, we came across a hatchling resting a short distance below the surface.  It was a flatback turtle – the first evidence ever that flatback turtles have nested on that beach.  The little guy “woke up” and was in decent enough shape to release.  Rather than carry him/her to the water, we may sure that s/he ran across part of the sand to the water.  Female hatchlings will return to their birthplace when they are ready to nest, and this short run across the beach might be the only chance for the location to be imprinted on the baby turtle.  Based on the DNA results from previous green turtles at this beach, we already know that those turtles represent a separate management rookery. 

As we continued with the exhumation, we found 2 more flatback hatchlings.  These two were under a big piece of coral (which are normally cleared out by the nesting adult), so we may have actually rescued them.  Flatback turtles have smaller clutches than greens, and we determined a 97% hatch success rate with 37 eggs for this nest – an excellent rate.

We did see one other turtle during our trip.  There was another group surveying wildlife in the wetlands for a few days.  They came across this hawksbill turtle (maybe a year old) which had wrapped one of its flippers in some fishing line.  They planned on bringing the turtle for a vet check, but they swung by our camp to show us (they had heard of our lack of turtles).

So what did we do with the rest of our time there?  Because our “work” consisted of moonlit beach strolls at night, we had a lot of free time during the day.  I tried to do some exercise early in the morning before it became too hot.  In the afternoons, we read (I now know about turtle fibropapillomatosis), took naps in hammocks, and played cards (lots of crazy 8’s!).  Some folks were into bird watching.  I did spend a morning exploring nearby tidepools.  Basically, we relaxed heaps, which is easy to do when you have awesome sunsets at camp every night.

As time passed and we grew bored and disappointed in our lack of turtles, the very generous rangers took us on a couple of boat rides, which was excellent to break up the days.  We also did part of the coastal scenic drive (where we saw those giant croc tracks and sharks hanging out in the shallows), which added more species to our lists.  Mine includes Banteng; Garig Gunak Barlu is home the largest wild herd of these Indonesian cattle. 

Although the area was quite beautiful and abundant in other wildlife and I enjoyed learning from and hanging out with like-minded people, I cannot help be a little disappointed in nature.  I know that our lack of turtles is interesting from a scientific point of view:  Why didn't any turtles come ashore to nest during this time?  Was the timing off -- did they start coming in hordes after we left?  Was it an off year for nesting (turtles might have 2, 3, 4, or 5-year cycles)?  Were there certain conditions that made them go elsewhere?  Was this a sign of a population decline?  I also know that I was very lucky to see those 3 hatchlings that we pulled out of the sand, but I don’t think I can cross this item off my bucket list yet.  I’ll just have to try again sometime.