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Sapelo NERRds
Sapelo NERRds
Turtle Recall: The Nest Quest
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Join us as we cover our second annual Sea Turtle Podcast from Sapelo. You'll hear from this year's sea turtle technician, Joyce Sykes, as she shares a live nest excavation and the secrets it reveals about the turtles' incubation period and nest success.
To track the sea turtle nests on Georgia's beaches, click here.
For more information from the sea turtle technicians and updates from the GA Sea Turtle Cooperative, click here.
Hi and thanks for joining Sappalo Nerds, a coastal science podcast. I'm your host, corinne.
Speaker 2:And I'm your host, Brittany, and we work at the National Estuarine Research Reserve, or NEAR on Sappalo Island, a Georgia barrier island Hmm Reserve, or NEAR on Sapelo Island a.
Speaker 1:Georgia barrier island. Oh, brittany, you sound so sad, are you okay?
Speaker 2:I mean, I guess it's kind of just the end of the season and I'm so bummed. Summer no, not summer, I'm talking about sea turtle season Of course, sea turtle season.
Speaker 1:It is sad when the sea turtles are gone, but sometimes good, I mean they make it out to the water.
Speaker 2:Yeah, so from May till October, typically it is sea turtle season, and you've heard us talk a little bit about sea turtle season here on this channel and if you missed last year's episode in which we interviewed Matt, our sea turtle tech for 2023. You mean, keep calm and turtle on, exactly. If you missed that episode, please go check it out, because it's really important to have some background information for what we're going to do Today we get to share a really cool in the field episode of an interview with this year's sea turtle technician, Joyce.
Speaker 2:Yeah, and we're going to go over some really cool things that Corinne discovered with her, including the fact that sea turtle season is beginning way earlier.
Speaker 1:Yeah, joyce came out to the island in mid-May, but we're actually starting to see. Although we used to say that sea turtle season started about May 1st, they may come up even earlier. They're talking about bringing sea turtle technicians out in potentially mid-April.
Speaker 2:And that can have a lot of implications for people who are living or visiting our beaches. Things like dogs on the beach and making sure we turn off our lights at night to prevent the turtles from going in the wrong direction, and even things like making sure that we cover up our holes when we're digging in the sand, are really important to do earlier in the season now than we originally thought.
Speaker 1:And the reason why our sea turtle season is starting even earlier we can tell through our system-wide monitoring program or swamp data. Earlier we can tell through our system-wide monitoring program or swamp data. We have a steady record showing that water temperatures are warming, which means those mama turtles are getting their seasonal cues to start laying nests sooner. This can actually have big implications for the population of sea turtles. If the sea turtles are coming up sooner, it means those nests usually have to incubate a little while longer, which means those nests are usually a little bit cooler and that slight temperature variation can actually mean there's more male turtles than female turtles.
Speaker 2:And because it's happening earlier. Whenever the nests are out during the warmer end of the season, those nests are actually incubating a shorter amount of time and producing tons of females, Since we talked about in our last episode that sex can be determined by the heat of the nest.
Speaker 1:So we want to make sure that all of these turtles that are coming up to our Georgia beaches are staying nice and healthy and safe and that we're not impacting the population too much with these different temperatures. That's because the turtles that we have here in Georgia are part of the northern recovery unit of sea turtles.
Speaker 2:Northern recovery unit turtles.
Speaker 1:So these NRU turtles are actually distinct from the ones that are nesting just across the border in Florida. They tend to stay further south, while our turtle population or turtlation ends up staying further north, so they don't interbreed or spread out further south very often. This is a really unique collection of turtles that isn't going to spread out very far or won't get replaced very easily if we lose them.
Speaker 2:That's why it's super important that the monitors the local population and how many turtles we are seeing hatched on our beaches. We're super excited that this year, instead of just interviewing our sea turtle tech in our studio, aka Corinne's office, we were actually able to go and do an in the field podcast episode.
Speaker 1:And this one wasn't as bad as our other one that we did in the field where it was super windy on the beach.
Speaker 2:We promise we've gotten better mics.
Speaker 1:All right, so we are out here on Nantigo Beach on Sappalo Island and I am with Sappalo's 2024 sea turtle technician, joyce Sykes. Hey, joyce, hi, nice to be here with you. Yeah, thank you so much for letting me come out and bother you. Nice to be here with you. Yeah, thank you so much for letting me come out and bother you. So we are working on what we call a nest excavation or sometimes a nest inventory.
Speaker 3:Can you explain what that is? Yeah, so we conduct nest inventories to basically get a sense of what happened in a nest during the time that it was incubating. So we do two different types of inventories. We'll do one either five days after a nest has hatched or we do one on day 70 if we didn't see any sort of activity of a hatch during that period.
Speaker 1:So if you're looking for a hatch, you're looking for a bunch of tiny, adorable little tracks leading to the water Exactly.
Speaker 3:There's usually a pretty distinctive hole right where the eggs would have been, and then we'll see all those distinct little hatchling tracks heading towards the water. But sometimes we miss it. If there's high wind or if it's raining, those tracks get washed away pretty easily. So just to be safe, we'll wait the 70 days and just do an inventory later.
Speaker 1:So how long is a typical incubation period? How long are they typically in the ground?
Speaker 3:It can be anywhere from 50 to 70 days, but the average on Sapelo has been consistently around 55 days of incubation.
Speaker 1:Awesome, and do we know if that's changing at all, like so we're getting warmer. Do we know if those are going down or up, or is it staying pretty consistent?
Speaker 3:it's staying pretty consistent, at least here. On sapelo um, which is good news. It really is dependent on um where the eggs are being laid to, so if a lot of the nests are high in elevation, it can take them longer to hatch as well. So so I would say that that seems to be the cause. On sapwood here.
Speaker 1:Interesting.
Speaker 3:Okay, so elevation can make a big difference, so in addition to elevation, time also plays a big, a big role in this as well. So the nests that were laid earlier in the season typically have to incubate for way longer. So sometimes we'll see hatch rates or they'll start hatching on like day 70, which is way later than we would normally see if they were laid later in the season. And also there's a huge impact of time on sex ratio in the nest as well. So the longer that the eggs are incubating, the more likely you're going to have males. So if it's really, really short, if it's just at like 50 days or early around 48 days, that nest is probably going to be almost all female. But the longer the eggs are sitting there, the more males you'll get.
Speaker 1:Okay, so that has to do with the fact that turtles are temperature-determined sexes or genders, right? Yes, so the males are cooler temperatures, the boys are cool and the females are hot right Exactly.
Speaker 1:Okay, awesome, that is so cool, so that makes sense. It's a little cooler earlier in the year, but once it's hot in the summer, they're baking, they're cooking pretty quickly, right, exactly, awesome. So to kind of set the scene before we start diving in, here we are sitting on the primary dune, we are surrounded by beech tea, croton and sea oats, and there are just Gulf fritillaries and dragonflies everywhere. If you can hear the sounds of the waves behind us, it's just absolutely gorgeous out here, and so we're gonna start by digging a hole, right, yeah?
Speaker 3:exactly. So we're basically recreating what the mom did when she came to lay the nest. So we can feel the difference in the mom did when she came to lay the nest. So we can feel the difference in sand density where the nest is laid. I can basically feel that the sand is really soft and it's really easy to kind of sink into as compared to all the sand around it. And so I just kind of go into the hole and remove all the sand on top and the nest is usually about a foot deep or so, and that depends on basically the size of her back legs, flippers, exactly, yeah, or her back flippers Whichever, but exactly it depends kind of on their size, and if the mom was disturbed as well too.
Speaker 3:Sometimes if they're in a hurry they'll lay like a really shallow nest just to be done with it and turn around okay.
Speaker 1:So while you're digging up here, you're setting some of the sand aside if you can tell it's just sand, and then, if you can feel eggs, you're actually putting it into a like gridded seed, like large mesh sieve.
Speaker 3:Yeah, it's kind of like a large sieve. I'm basically using it as a sifter. So it's this big wooden box with like a metal grate at the bottom, and I'm putting all of the contents into there and it just lets us kind of sift through the contents of the nest a bit faster. So, um, at the end, after I scoop all the contents out, I'm going to shake it and so all the sand will fall out and we'll just be left with, hopefully, just the eggshells and anything else we find.
Speaker 1:Awesome. So we can already see there's fire ants crawling around. Fortunately not a ton.
Speaker 2:We're not getting attacked?
Speaker 1:Not yet. Not yet, and we can see a few ghost crab burrows around, so that might be evidence that we could expect some predation in here.
Speaker 3:Is that right? Yes, so that's evidence that there might have been some sort of predation. When I find this nest every single day after I come and I look at the nest and we try to see if there's any signs of predation. But there was originally a protective screen over it. So that protective screen is like this really big plastic mesh that we put on top of the screen and it usually helps stop coyotes or raccoons or any big predators that are going to get a lot of eggs stop from getting in the nest, but it can't stop ghost crabs because they're too good at their job.
Speaker 1:They're pretty good at digging holes. We see lots of those burrows around our dunes, so that's awesome. And here we have. The post that's next to this nest is N-94, so nest number 94. And it has an I, which means in situ, right, yes, so why does it have in situ versus R for relocate?
Speaker 3:So that means that this nest was left exactly where the mom laid it. So we didn't do anything to it other than find eggs to establish that it was a nest, and we actually took one egg as a genetic sample. But other than that, we left it untouched. We also put a screen on top of it too, which is we can tell, because we mark it as T2 for the second treatment, which is putting that screen on top of it.
Speaker 1:So a lot of places. People might think that putting the post over it and the mesh over it and signs near it is for people, but one of the primary uses is to make sure we keep predators out Exactly.
Speaker 3:We've had basically a 100% success rate of keeping out bigger, anything bigger than a ghost crab If you, especially coyotes. If you put the screen on top you might see a few little paw prints around it, but they do not try to dig up the screen, at least on.
Speaker 1:Sapaloo and we have coyotes out here, which are a problem. We also have hogs. We do.
Speaker 3:They don't seem to be an issue here. In the past there have been a few instances, but it really hasn't been as much of an issue. Since the coyote population has increased, They've kind of been keeping them away oh, interesting, as well as raccoons. In previous years raccoons were the biggest threat, but now it's coyotes.
Speaker 1:And on most beaches they cover all of their nests with that predator screen and do the marking. But, like you said, this is treatment two. So we have four different treatments we do here on Sappalo right.
Speaker 3:Yes, so treatment one is also in situ nests. So that's just where we leave it and we don't put a screen on top. We just kind of let nature do whatever it wants. And this one for treatment two we leave the and we don't put a screen on top. We just kind of let nature do whatever it wants. And this one for treatment two we leave the nest in place but we put a screen on top. Treatment three is when we relocate a nest. So whenever I find a treatment three nest, I will take all the eggs from it and move it to usually further back in the dunes so that it won't be washed over by a tide. And then treatment four kind of gets the whole suite. So we put a screen on top and we relocate it.
Speaker 1:We're doing the relocations as kind of a research purpose, to see what happens when we relocate nests. But other places have to, like you said, so they don't get inundated by the tide. There are areas where they have to relocate nests in order to protect the eggs.
Speaker 3:Exactly so. Here it's more for research purposes. So no matter where I find a nest, if it's a treatment three or treatment four, I'm going to relocate it no matter what, and we just try to have it at a place that we don't think will get washed over at all during the season. And we're mostly doing that to help get some data on the effectiveness of relocation, if it actually works and if it affects emergence and hatchling success. Because that has been a concern in the past, that if you take all the eggs from a nest and move it to a new spot, what is that going to do to the a number of hatchlings that can actually come out of a nest and move it to a new spot? What is that going to do to the number of hatchlings that can actually come out of the nest and actually make it to that point of development?
Speaker 1:Awesome. So we know that relocations can be a little risky. So what are some things that you do to like minimize that risk? Is there a time frame involved with how quickly you need to do relocations, or is there a specific way you need to change or move the eggs?
Speaker 3:So a few of the things that we do is, like you mentioned, time. We typically try to get to the nest within the first 12 hours of it being laid. So that means especially early in the season. I get here as soon as, like, the first rays of light are out, just right as the sun is rising Early early morning, exactly, early early morning. Luckily it's a bit later now, but we do that to try to minimize any disturbance. That we're doing and we are trying to catch the eggs before the embryo is actually attaching to the eggshell. That is when any sort of misorientation could occur. So orientation is really important to hatch, to developing hatchlings, because when they actually hatch they might not know which way to go if we're like moving the eggs too much, disrupting them while they're still developing and the embryo is still trying to attach awesome, okay.
Speaker 1:So you've got to get out here super early, early in the week, and this morning we got started about 9.30. You started packing out.
Speaker 3:Nice 10 o'clock start is good Exactly Now that we're not really getting new nests, that time frame is not as important and we can kind of take our time, but when you're finding new nests, that time is really, really crucial. And but when you're finding new nests, that time is really really crucial. And also just trying to keep the eggs in one orientation as well, not like playing catch with them or anything crazy, can really help you with the hatching success, right.
Speaker 1:Okay, All right. So you have reached in about shoulder deep and you just started feeling just sand. You think you got all the eggs out now.
Speaker 3:Yes, luckily for the in situ nests the border, like the boundary of the nest, is usually pretty distinct, so I can kind of tell when I've gotten to the bottom of the nest. It just feels like hard sand all the way around.
Speaker 1:And generally we say that a nest shape is almost like an upside down light bulb, which makes kind of sense just based on what she can reach. So that's been pretty firm. We've got a good collection of eggs in here, so what are we going to do next? Or eggshells mostly.
Speaker 3:So next, I actually just shook out all the sand and I'm going to sort the contents now into different categories. So I'm going to try to find all of the eggshells that seem to be 50% or more of an egg and I'll count that as one hatched egg. So if it's just an eggshell with nothing in it, just kind of empty, empty shell that seems like more than 50%, then that's one hatched egg and that's a sign that the hatchling actually came out of the egg and was in the nest. And I'm also looking for any unhatched eggs, and we seem to have a few here. So they're basically any eggs that haven't broken. They're still clearly fluid inside or sometimes they're a little open and you can see the yolk, but that's a sign that the hatchling didn't actually finish developing.
Speaker 1:And those kind of things either the unhatched eggs or ones that are partly cracked open are one of the reasons why gloves are normally really good to wear because you can get kind of soupy in here right.
Speaker 3:Yeah, well, gloves if you're not up for the challenge. I think that's part of the job, so it can be a little gross. Exactly, yeah, definitely. This is a nice one. I've definitely seen worse.
Speaker 1:And this one. What we haven't seen are any stragglers, so can you explain what a straggler might be or what they are?
Speaker 3:Yeah, so a straggler usually a fun surprise. We typically only see those after a nest that has hatched and we're coming in to do an inventory five days after because the straggler refers to any um hatchlings that didn't quite make it out of the nest and are just kind of sitting there waiting to come out. Usually that's because um actually emerging from a nest is a group process so all of them need to kind of work together and hatch at the same time to come out. So if there's a few really small guys at the bottom, sometimes they just don't quite make it out and we can help get them out of the nest if we catch them. But in this nest it seems like any of the hatchlings that did actually hatch out of the egg made it out, Because I don't see any stragglers. I don't see any dead hatchlings or any sign that they weren't able to emerge.
Speaker 1:So we've taken a second. We dug out all of the eggs and we counted them. We counted how many hatched and how many didn't hatch. So what were our totals?
Speaker 3:So we had 50 hatched eggs and 41 unhatched, so for total that would be around 90 eggs that were originally in this nest and that information is helpful because we didn't do a relocation on this one so we didn't know how many eggs were in this nest until just now. Oh, yeah, Okay.
Speaker 1:So what does that tell us? What does that matter? Why are we counting the eggs?
Speaker 3:So that tells us both the hatch success and the emergence success. So the hatch success is determined by how many hatched eggs there are and you just divide that by, like, the total amount of eggs. Basically, if you have more hatched eggs than unhatched like we do in this case, that's usually pretty good. That's a pretty good sign. This is a successful nest. Usually you're going to have some amount of unhatched eggs. It could just be anything from moisture, temperature or just maybe that egg was never going to actually develop. But I would say that this was a fairly successful nest, especially since we didn't find any stragglers stuck in there or any dead hatchlings means that the emergence success was also very high.
Speaker 1:Awesome. So we're trying to understand just how many actually made it out of an egg and then how many actually made it out of a nest Exactly, and even though we're only looking at 50 compared to 40 for eggs, hatched eggs and unhatched eggs, that's actually pretty good numbers, yeah, exactly.
Speaker 3:That is something that we're looking at on a larger scale as well with the different treatments that we've been using. So since this is a treatment to the screen, we left it in place and this data will help us see how the screen can help affect hatching success. Typically, so far that what I've seen this summer, there's a way higher hatching success for, and emergent success for, the nests that have some sort of protective covering over them. And we can also compare different treatments like treatment number one and treatment three, which are using no screen at all, it's just the relocation and we've seen with that they seem to have a more similar hatching success and emergent success. So it's not as much of a difference between whether or not you leave a nest in place or you relocate it. At least on Sapelo we haven't seen that it greatly increases hatching success if you relocate a nest, other than it might stop a nest from completely getting washed over from the tide.
Speaker 1:So relocations are good to keep things out of the water, not having a huge impact on how many actually hatch or emerge. But the predator screens are good. We're seeing that the data shows us predator screens are important.
Speaker 3:Exactly so this kind of follows data that we have seen in the past, because this is a really long running project that's been going on for like 25 years or so. That relocation should probably be done when you know for sure, or are pretty sure that a nest is going to be washed over and it's not going to last. But if that's not the case, it's usually best to just leave it in place and put a screen on top.
Speaker 1:Yeah, and this can be really hard to tell about that high tide line. Especially this time of year. We're getting really high tides. You're having a hard time getting out on the beach until the tide line goes down.
Speaker 3:It's been really hard to predict, especially since the hurricane we had last month, I think. Since then, our tides have just been crazy, crazy high, and nests that haven't been washed over all season have been suddenly getting washed over, and so that's been skewing our results a little bit as well. So it's important to do this over a long period of time.
Speaker 1:And is it guaranteed that if the sea turtle nest gets washed over one time, that, like the, the nest is lost? Or might they be okay?
Speaker 3:They might be okay, so it depends on the level of inundation. So how much water actually got into the nest? If it just gets washed over once, lightly, it's probably fine, but if it gets, if there's a lot of tidal activity, if it gets really washed over and there's standing water and it's just completely sunken into the nest and it's really soupy down there, that nest probably will not hatch. We have seen, though, that nests can usually make it till about three wash over events, and that's when it really starts affecting the hatching and emerging success.
Speaker 1:Okay cool, really interesting. So this was nest number 94 out of how many on Saplo Out of 133. 133. Okay, so that's not our highest year, definitely not. We had about 100, a little over 100 more nests last year, but that's normal, right?
Speaker 3:So we have been seeing a kind of cyclical pattern with the loggerhead nesting on the Georgia coast and typically every three to four years there's kind of a drop. We just have a lull, and that can have anything. That could be anything from just like when these turtles are actually reaching sexual maturity. When you have a lot of moms on the beach, they're laying a lot of eggs and then they go out, reach sexual maturity at the same time and come back and nest at the same time. So it's just a cycle that we see and it's something that we expected and are able to model.
Speaker 3:So next year we'll probably see a few more nests than this year.
Speaker 1:Because this takes a lot of energy. These mamas are coming up and laying three to five nests in a nesting year. It these mamas are coming up and laying three to five nests in a nesting year. It takes a lot of work, lots of energy, so they usually don't nest every single year either. Right, exactly, awesome. So this is towards the end of the season. This nest was laid on July 9th, based on the information on our post.
Speaker 3:So this was one that you didn't catch the hatch on right? Yes, so this nest is at the top of a dune and it's covered by, like a lot of vegetation, so sometimes, when there's a lot of wind or rain or we just sometimes, don't see those little small hatchling tracks. Um, it's not a huge deal and we usually wait until the 70 day mark and let the hatchlings come out on their own instead of marking a false hatch, because that would be way worse for our data if we were just like. I think it probably hatched around 55 days, so we would rather just wait and see and count all the eggs, so we gave it some time to kind of finish hatching on its own. But, yeah, so this nest probably hatched around the 50-ish day mark, but we won't know for sure. All we can do is go off the data that we found in the nest.
Speaker 1:Sure, that makes sense. We've got to trust the data. So how many more nests do we have that either haven't hatched or that you still need to excavate?
Speaker 3:I have about 10 that I still have to excavate, which is crazy to think about. The season has gone by so fast. I feel like I was just stressing over all 100 and something nests that I was working with and now there's only 10.
Speaker 1:So, yeah, so is it going to be a little bit of culture shock? You've been out here on Sappalo since May. Yeah, early May, since May 14th is my first day.
Speaker 3:It's going to be crazy going back to like the suburbs All the people, all the people. Away from the water too. I don't have easy access to the water.
Speaker 1:Oh yeah.
Speaker 3:You're going to miss it a lot.
Speaker 1:So what's something that you're looking forward to, though?
Speaker 3:going back to civilization, I'm looking forward to a warm bath that doesn't have gnats in it and trader joe's I miss trader joe's.
Speaker 1:So thank you so much for letting me come out and hang out with you, joyce. We really appreciate you kind of walking us through an inventory. Yeah, no, no problem. Well, I hope y'all liked this lesson on turtles today, or what we like to call it a turtorial, like a tutorial.
Speaker 2:Tutorial and maybe it looked better on paper. Yeah, I think that was one. That probably isn't a podcast joke, that's a written down joke, but but I got one for you. A policeman in a big city stops a man in a car with a large turtle in the front seat. The police officer exclaims what are you doing with that turtle? The guy goes well, I'm taking it to the zoo. The following week, the same policeman sees the man with the turtle again in the front seat, with both of them wearing sunglasses. The policeman pulls them over. He says I thought you were gonna take that turtle to the zoo. The man replied I did. We have such a great time. We're gonna go to the beach this weekend. That sounds like you last week.
Speaker 1:yeah, it's a normal day. Well, at least they're not, you know, hurting the turtles. I mean, I'm not vegan or anything, but I do think it's pretty messed up that they make sweaters from turtlenecks, oh hooray. For more information about any of the topics we covered today, or to submit your question that may be featured in our upcoming episodes, please email us at signersocials at gmailcom. That's S-I-N-E-R-Rsocials at gmailcom.
Speaker 2:Thank you for listening to Sapelo Nerds, a coastal science podcast brought to you by the Sapelo Island National Estuarine Research Reserve. Please check back for more episodes released on the 1st and the 15th of each month and that's the saddle of sound.
