The first time’s the charm

The first nine days of surveys started with the same routine: wake up, eat breakfast, avoid kangaroos along the drive to Gnaraloo Bay, survey the beach and return home, all before 9 am… a pretty nice and relaxing way to start the day, right?! It was delightful, except for one small hiccup… where were the turtles? After 2 weeks of intensive training, we were starting to place bets on when the first nest would occur and as day ten rolled around, the four of us Interns were starting to conjure up wild ideas about how our Program Assistant Simone was really playing this elaborate game by hiring us, and there were actually no turtles at Gnaraloo.

4:20 am signalled the ringing of our morning alarms on the 10^th of November, and Heather and I were soon rolling out of our beds to follow the same routine that had been danced out over the previous two weeks. As the first rays of light started peaking up over the horizon, we drove to the start of the Gnaraloo Bay Rookery, wondering along the way what the beach would have in store for us today. I dropped Heather off at the Gnaraloo Bay North (GBN) marker and we wished each other good luck before I continued my journey further up the beach.

Survey started off as usual with the cool winds blowing along the dunes as the air temperature slowly increased with the rising sun. Walking above the high-tide line, the first sub-section of the beach did not turn out fruitful. With the close inshore reefs edging the rippling low-tide and the steep dune marking the high-water mark, this has been the least active section of the rookery within previous seasons, so the lack of activity was not completely unexpected.

Moving into the uppermost section of the survey area between Beach Point 8 and Beach Point 9, the dunes continued their graceful flow along the edge of the beach stretching northwards towards the tip of the bay. Continuing along the beach, I came across a strange mounding of sand which seemed to be stretching up the dunes slightly. Although very windswept, I felt a creeping suspicion that this could be my first turtle track of the season.

Approaching the strange grooves, I noticed that they were edging a long pit which seemed to be heading up the dune – although the beach was very windblown making it very difficult to identify what was going on. My first track definitely wasn’t going to be easy and I was about to be tested on everything that I had learnt through our training weeks. Scanning the area carefully, I identified some flipper marks that seemed to be moving up the dune, creating an emerging track approximately 3 meters to the left of the pit.

When identifying turtle tracks, we most commonly see Loggerhead turtles (Caretta caretta) here at Gnaraloo. Walking with an alternating gait, the Loggerheads use their hind flippers to push them forwards. On the other hand, Green turtles (Chelonia mydas), which is the only other species occasionally seen here nesting, use their front flippers simultaneously to pull them forwards creating momentum up the sandy dune. At first glance, the uphill emerging track closely resembled Green turtle tracks as the flipper marks sat very close together almost symmetrical in placement. This remained true until the tracks reached a bush further up the dune and the female had turned around to find a better location to start building her nest. Moving along the flatter surface, the flipper marks started to spread out and moved with an alternate gait. Thus confirming her identity as a Loggerhead turtle.

Following the track along the dune, I came to the beginning of the pit that I had noticed earlier which connected to the strange grooves in the wet sand along the high-tide line. Using the 6 criteria for identifying a nest, I slowly ticked off each characteristic which corresponds nicely with the different stages of building a nest. Firstly, I identified (1) misting – as the female starts to create her initial body pit, she covers some of her emerging track as she flicks sand behind her. (2) Mounding comes next, after creating an egg chamber and laying her clutch, the female starts covering over her nest using her hind flippers, this often leaves a small mound of sand close to the start of her body pit indicating the location of her egg chamber. After covering the egg chamber, the female starts to camouflage her nest by throwing sand behind her as she moves forward and back towards the water, this often creates (3) aerated sand, which feels fluffier and less compact than the surrounding area; (4) loose vegetation, as the female rips out vegetation as she moves past and (5) an escarpment along the edge of the pit. Once the female is content with the amount of camouflaging that she had undertaken, she starts to move back towards the ocean creating a return track. The sixth characteristic of a nest is the (6) secondary body pit, this is body pit created within the camouflage just before moving off and back into the water.

My first nest followed the first five criteria however as the high-tide had crept up the beach overnight, the secondary body pit had been washed away, explaining the strange grooves originally seen in the wet sand. After confirming that this indeed was a nest, I started to take measurements of the track width and the distances to the high-tide line and nearest vegetation, along with taking a GPS point and surveying the area for any signs of disturbance or predation. Finally, I placed a stake one meter behind the suspected egg chamber to enable us to continually monitor the nest throughout the season.

Before leaving the nest, I took lots of photos of our first new nest so the rest of the team could confirm what I had seen and I continued along the survey which a renewed spring in my step. The turtle nesting season had finally begun!

By: Megan Soulsby