First Week! Track Survey, Night Patrol, Pool and baby Hawksbills!
Tortuguero
beach, Costa Rica, is a black volcanic sand beach which extends for 35Km along
the Caribbean coast and lies within Tortuguero National Park which was established in 1975, protecting the entire beach, and 18,946ha of
surrounding tropical wet forest that encompasses most of the Tortuguero water
basin. The beach hosts the largest remaining green turtle rookery in the
Atlantic basin, meaning its physically impossible to mark, tag and measure every turtle and nest. For this reason as well as night patrols where research assistants tag and measure nesting turtles, track surveys are completed each morning to count the number of new turtle tracks and nests on the beach the following morning to get an estimate of the number of nests each night.
The point of the morning track survey is to count how many sea turtle tracks there are on the beach from the night before, as well as the number of nests to calculate how many were false crawls/half moons (didn't nest), as its physically impossible to count, tag and measure every turtle that nests on this beach at night and in the dark. I was out on Boca for my first Survey with the Project coordinator Keilor, who told me we're about to reach the peak of the season around the end of August so the number of turtles is going to increase a lot in the coming weeks.
We found lots of new tracks, they're slightly smaller than the leatherback tracks I used to see in Grenada, but they're still huge and look like tyre tracks up and down the beach. I was given the job of counting the tracks whilst Keilor counted any new nests in the vegetation area and noted if any were poached or predated. We also looked for signs of dog prints, racoon prints and Jaguar prints or any dead turtles that had been predated (thankfully found none this time, but as the peak season more Jaguars will arrive to predate on nesting females).
Once a track is seen (not difficult as they're everywhere) its normally not too hard to see if its new or old as the fresh tracks have darker sand and more pronounced marking where as the older ones are more faded, but to help make sure we don't double count any of the tracks we have to draw two lines through the tracks as we walk along the beach, which was quite tiring as you have to make sure they're nice and deep to last a few nights until the tracks fade. Any new nests that had been marked the night before also had to be checked by checking out the triangulation measuremtents the night patrol team had written down. The survey took us around 3 and a half hours with a couple stops as I felt a little dizzy in the sun at some points but the sun went in for the last km and I felt much better by the time we came to the end of the survey.
The rest of the day I spent working on my research project and completing some training ready for my first Night patrol on Sunday.
I was trained on how to apply metal tags and PIT tags to green turtles. I've applied metal tags to leatherbacks when I was in Grenada but they're tagged in a different place so its a bit different. Leatherbacks are tagged on their rear flippers and greens are tagged on their front flippers. The PIT tag is like a microchip which we insert using a PIT gun which is a small hand held device with a small needle like part at the end which is inserted just above the shoulder joint of the turtle so we can scan them for ID. I was also shown how to measure the straight carapace length (using very large calipers), which is the distance from the top of the carapace to the bottom, and curved carapace length using a measureing tape.
My first Night patrol was last Sunday and I was very excited to get back out in the field and work with some turtles. The patrols are very different to the ones I was used to in Grenada - we are split into pairs and work four hour shifts, only stopping to 'work' a turtle if she is ready to dig a nest chamber so we can count her eggs, triangulate to mark the nest and then check for tags, tag if needed and then measure and check body condition. Otherwise if we find a turtle laying, covering or camoflaging her nest we can 'work' her and check for tags, tag if needed and measure and body check if possible. Whereas when I was in Grenada we would stop for every turtle we found no matter what phase we found her in, there are so many more turtles nesting on this much larger beach that its not time efficient to wait with every turtle. There are also tourist groups who have priority until 00:00 so if the guide is with a group they have priorty to watch the turtle lay its eggs over us marking the nest and counting eggs.
I had a really great first night, tagging green turtles is very different to tagging leatherbacks, for one they are much more sensitive and react more when you tag them, and you're also working much closer to the head and the front flippers can also move a lot more so it makes it a bit more difficult. I tagged a couple of turtles and helped measure, as well as counted eggs for one nest but didn't manage to PIT tag a turtle as the four we worked were a little sensitive and I wasn't quite fast enough at inserting the needle. I decided to opt to do an extra night survey on Monday in the hope of being able to PIT tag. We also recieved a new eco-volunteer on Sunday as well so she joined us Monday to do her first night patrol as well.
Monday night I successfully PIT tagged two turtles, one with the guidance of Keilor and the second by myself which I was very proud of, we thankfully found a turtle who was just covering so she was moving a lot less than a turtle who has started to camoflage the nest. The night surveys are also quite funny because we have to walk with all our lights off and only turn them on when we are working a turtle (even our red ones as the turtles at Tortuguero are very sensitive and we want to reduce the chance of them false crawling ) but it means your eyes have to adjust to the complete darkness which takes a while. This makes it difficult to walk as it is but there was also a really bad tropical storm a few weeks ago apparently which has brought in a lot of logs and debris which you have to try and dodge in the dark, but inevitably we all tripped up multiple times throughout the night! As well as all the logs tripping us up green turtles do something called bodypitting when they first emerge and are looking for a place to nest, which basically means they flick sand and move their bodys to create a pit which they might decide to then nest in or move on and start again somewhere else. These pits are even harder to see in the dark and I've ended up falling into multiple of them each night which is highlighy amusing to whoever you're walking with!
On Monday afternoon I went to a local hotel with the rest of the research assistants to use their swimming pool which was good fun :)
The night patrols are split the same way the track surveys are split into 'Boca' and 'Park' My first three night patrols were on Park, which is towards the national park and means you're more likely to see Jaguars! I haven't seen one yet but I have seen their tracks in the sand and we did see a freshly dead turtle on my Tuesday Night Patrol.
On Tuesday afternoon the staff were excavating a hawksbill turtle nest which was relocated as hawksbills are critically endangered and the STC want to reduce the change of poachers taking their eggs. When we went to excavate it and see how many hatched, the eggs weren't fully hatched but the nest was infested with Ants so Keilor and Gloria the project coordinators made the decision to remove the eggs from the nest and bring them back to the centre to finish incubation here. Some of the eggs were beginning to hatch and they were also brought back to allow them to finish hatching and be released when they were more awake and at night. It was a really exciting afternoon as I'd never seen hawksbill hatchlings before and they're so much smaller than leatherback hatchlings.
That evening I had another night patrol (my third in a row) where I saw many more green turtles and I think we worked around 3 or 4 turtles that night as well, however it was raining torrentially pretty much the entire night
On Wednesday Roldan, the Scientific Director of the STC and my external project supervisor arrived at the centre with a group of volunteers so it was really nice to meet him in person. Wednesday was also my first day off so I went into town with a few other volunteers in the evening to celebrate as it was one of the research assistants last nights before she left to go home.
Thursday morning I had my second track survey, again at Boca with a research assistant called Rashi, this time I was given the job of counting new nests and checking on old marked nests instead of counting tracks. On the way we saw a crocodile in the river which was very cool! The survey took around 3 and a half hours again but the weather was much cooler and it actually rained for the last half an hour. I was also on Kitchen cleaning duty on Thursday so it was my job to clear away all the left over food back to the fridge, sweep, wipe the surfaces, wash up old food containers and take out the compost bins. I had Thursday evening off and enjoyed an early night to bed. Unfortunately my roomate tested positive for Covid on Thursday so I was moved out of our shared room and into my own personal room in the staff building with an ensuite which has actually been quite nice, but I think Suu has to be in isolation for a week so hopefully she is feeling better soon.
Yesterday was Friday and I spent most of the day working on my project, I also decided to visit the STC visitor centre/museum we have on site which I hadn't been to yet which was really cool. We also released the hawksbill hatchlings that were removed from the nest earlier in the week yesterday evening which was so amazing to watch them all scuttle down to the sea and swim away, one of my favourite things to watch. A Hawksbill turtle was also seen nesting in the day outside one of the beach hotels but unfortunately I missed it, I was really gutted as I've not seen a hawksbill nesting yet but maybe I will before I head home. But releasing the babies definitely made up for it. I was also on Night Patrol for Boca with Aniol and we worked two turtles and marked one nest. I enjoy marking nests as it means we get to count eggs which is my favourite part, as well as getting to put the data loggers in the nests which is where all the data for my research project comes from - the data loggers in the nests- so it's really cool to see the method in action.
.jpg)
This morning I was also on Track Survey for Park with Sebas and we saw loads and loads of tracks. We also saw Jaguar tracks and a couple of old dead turtle carcasses (nothing too fresh), but it was nice to see Park in the day rather than just at night! I was on kitchen cleaning duties again today and spent the rest of the day resting and working on my project. This evening I have the night off but will be back on Night patrol tomorrow evening :)
The weather this week has been pretty grey and rainy apart from the day I arrived and the day of my first track survey. It has rained almost continously all day all week otherise with intense storms at night whilst on patrol which has been interesting and very soggy! Although its still been humid but not hot, but I'm hoping for a little more sunshine next week.
*Photos from Nest excavations - these pictures were taken while we performed an excavation to determine hatching success on marked nests. Training and permits are necessary to perform these and to do so without authorisation is illegal.
Comments