13 Shorebirds and Plovers
About this episode
Shorebird chicks start communicating before they even hatch. Dr Kristal Kostaglou shares the lives of Australian shorebirds, including Red-capped Plovers and the tiny calls coming from inside the egg.
Episode illustration: Red-capped Plover
Dr Kristal Kostaglou is a birdwatcher and environmental scientist. She is passionate about filling knowledge gaps to improve the conservation of Australian animals and their habitats. Kristal completed her Bachelor of Environmental Science (Wildlife and Conservation Biology) at Deakin University. She then went on to complete an Honours and PhD in the novel phenomenon of shorebird embryonic vocalisations… or in other words, chicks calling from within the egg before they hatch.
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Kirsty: This episode of Weekend Birder was recorded on the country of the Bunurong Boonwurrung people and on the countries of other Aboriginal and Torres Strait Islander peoples from around Australia. I would like to pay my respect to elders past and present and recognize that sovereignty was never ceded.
Kirsty: Welcome to Weekend Birder. I'm your host and fellow birdwatcher, Kirsty Costa. In the last episode, Peter Murphy told us about the awe and wonder he felt when he saw migratory shorebirds landing in the Edithvale-Seaford Wetlands. So, friends, I've tracked down Kristal Costoglou. Kristal is an environmental scientist who is passionate about conducting shorebird research in order to help their conservation. Here is how Kristal discovered her love of birdwatching.
Kristal: I've always been interested in the outdoors and I've always loved wildlife. And as I was growing up, we always had pet birds. We've always had things from budgies through to cockatiels. We had some lovebirds at one stage, too. So I was always surrounded by birds, however, it was really during my Bachelor of Environmental Science that I completed at Deakin University where I really started to learn about just how cool our native bird species are. And then, of course, seeing the passion through all of my professors and in particular one of my professors who was really passionate about our shorebirds. It's what inspired me to conduct some more research on them and complete my honours and now PhD project.
Kirsty: Kristal has a fascination for birds, but it is shorebirds who have really captured her interest.
Kristal: So shorebirds... I think I kind of just really fell into this species, this group of birds. And I think my one of my professors, Associate Professor Mike Weston. He's done many, many years of research on Australian shorebirds and just seeing his passion for these birds. And he just made it seem like such a cool species to work with. And then once I had one day out in the wetlands and I was able to kind of experience it for myself. I just was drawn into their quirky little personalities, their differences in size and coloration, and they were just something a little bit different. And I think that's what really drew me into them. Shorebirds are essentially a diverse group of birds, and you can usually locate them near a body of water, so either by the sea or perhaps some wetlands that are further inland. You may also know shorebirds as 'waders'. They tend to get this name because they have these long legs that help them wade through the water. You'll also find them feeding along the water's edge so they'll use their bills to probe in the mud or the sand, or they may use them to flip over small shells or rocks. And they're looking for little invertebrates that they can eat. So we have about hundreds of different species, and they're found all over the globe. In Australia we have 17 resident species, so these resident species live here all year round. And then over our summer months we are joined by a range of other shorebirds and they migrate down from the northern hemisphere and they come down to enjoy our warm weather over the summer. They like to fatten up and eat all of the nice grubs that we have. And then when our winter and the cold weather starts to come in again, they fly back up north to go back over to the northern hemisphere for the summer and then they will breed again. So those are our migratory shorebird species. And some of these species can fly for up to nine days straight, which is just so crazy. So I think the one that does the nine day straight is the Bar-tailed Godwit and they essentially fly from Alaska to New Zealand each year with sometimes without a break at all. And then they do that a few months later, six months later, they then fly back again. So it's this continuous cycle of this endless flying and traveling. It's crazy.
Kirsty: Recently a Bar-tailed Godwit set a world record with a 13,560 kilometre continuous flight from Alaska to Tasmania. Satellite tag data suggested that the five month old migratory bird did not stop during its voyage, which took 11 days and one hour. See the notes for this episode if you want to find out more. Kristal did her Honours research on something that hasn't been well studied in shorebird science.
Kristal: I was looking at the functions of the embryonic vocalizations in shorebirds. So these are the calls that the chicks produce when they're still within the egg. It's not very well known. It's not very well studied but there's been a handful of observations where people who are working on eggs of these different shorebirds, and yet they're starting to hear calls, even though there's not any cracking on the eggs or there's no chicks in sight or no adults in sight. And so it seems that these chicks, before they hatch, are actually starting to vocalize and starting to communicate. And so we're thinking that this will play an important role in the communication between the parents and their chicks.
Kirsty: That sound was Kristal's recording of a 28 day old Masked Lapwing chick calling from inside its egg. You probably know Mask Lapwings well. You might call them Spur-wing Plovers, or you might call them one of the noisiest birds in the whole entire world. Kristal studied the chicks of the Masked Lapwing as part of her Honours and then went on to research Red-capped Plovers for her PhD.
Kristal: It was just such a surreal moment when I first heard these calls coming from within the egg. I remember I was approaching a nest and I'd been surveying these eggs for quite a while. And I was starting to believe that this actually wasn't something that occurred because I'd been visiting all these eggs and not hearing any of these calls. But then all of a sudden, as I was standing near one of these nests, I could hear these chick calls and I was looking around with my binoculars trying to locate where they were coming from. And then when I looked down and I crouched down next to the nest, I realized that the calls were coming from within the egg. So from that moment on, even though I've heard probably thousands of these calls, it's still just so cool. It never ceases to amaze me how they can produce these beautiful, long, complicated calls. And yet they're not even hatched from the egg yet.
Kirsty: Wow! Mind blown! Let's find out more about plovers and what makes them unique.
Kristal: Plovers are a subfamily of shorebirds, and they have a range of species that vary in size from, let's say, an adult that probably would fit snug into the palm of your hand. But then there's also some larger bodied birds. So imagine the size of a magpie or a small chicken. So they have this great varying difference in size. They all seem to have a short, straight bill and you'll find that they feed in this stop and run motion. So you'll see them running along the water's edge. They'll come to a complete stop. They'll probe the sand or the or the ground with their bill, find something to eat. Then they'll stand back upright again, sprint off for a little short sprint and then stop. So it's really funny to watch them doing it, but that tends to be the way that they like to to run around and feed. So another thing about shorebirds is that they are ground nesting, so they actually create a nest on the ground. And so that is quite different to some of the urban birds that you come across in your day-to-day life. They lay their eggs in a beautifully constructed nest up in the trees and away from the ground. But shorebirds, they do the opposite. So what they do is actually dig like a little scrape in the bottom of the on the ground. And then they'll also line it with different materials. So they might use things like little shells or small small branches or some vegetation, and then they lay their eggs within that. So because these eggs are in such an exposed environment, they have a really cool line of defense. So the first being that these eggs are actually quite camouflaged to their surroundings. So if you were walking along by the beach, you would actually find it quite difficult to find one of these nests because the eggs will blend in really well to the sand. And same with the parents as well. And the parents also have a cool defense mechanism, which is a type of display. So it's a distraction display. So this is where they'll pretend that they have a broken wing or that they're injured and they'll distract the possible threat and lure them away from where the nest or where their chicks are. And you can see this really great footage where they've thrown their wings up in the air. They're crouched down on the ground. They're giving off these calls of like, "I'm in distress. I'm injured. Come follow me". And really what they're doing is just trying to get this possible threat or this predator away from their chicks or their eggs. And they also pretend that they're incubating some eggs or pretend like they're looking after chicks in a location away from where their real nest is. So they really are a smart bird. And they've got some tricks up their sleeve, that's for sure.
Kirsty: Through her PhD research, Kristal has become a Red-capped Plover expert. The good news for us birdwatching crew is that the Red-capped Plover is one of the most common and widespread of Australia's beach-nesting shorebirds. You might see them anywhere along the Australian coastline or inland, especially around salt lakes.
Kristal: [00:09:49] I guess the biggest standout feature on the Red-capped Plover is kind of in the name. The males have this beautiful red cap on top of their head and the females (like most birds), well, there is a colour difference between males and females. The males have this beautiful, nice red colouration, whereas the females have more of a dull red slash browny color. So there is that difference but apart from that, they are quite a small bodied bird. So like when I mentioned the sizes of the size range of shorebirds, the adult Red-capped Plover fits snug into the palm of my hand. A really a small bird. And then the chicks as well. They're only a few centimeters tall, so we like to call them little like cotton wool balls on sticks because they're just this tiny cotton wool ball sized bird with two long legs that just stick out from the fluff. And they're beautiful to look at. And these Red-capped Plovers, like I mentioned, can be located all across Australia. So you'll find them along sandy beaches or amongst the vegetation in the saltmarsh but they're also found inland as well. So whenever there's a wetland or a body of water, you'll generally find them there as well.
Kirsty: The differences in the male and females appearance, which we've learned in previous Weekend Birder episodes is called ‘sexual dimorphism’. This enables Red-capped Plovers to have very specific incubation periods to look after their eggs.
Kristal: During the day the female sits on the eggs. So whenever the sun is out, the female will be sitting tight on the eggs and that's because she tends to camouflage into the surroundings quite well. Whereas the brighter, more obvious male who stands out during the day will actually sit on the eggs throughout the night. Another researcher within my kind of cohort at Deakin actually was researching this kind of phenomenon, and they actually captured some footage of this occurring and it's pretty much like clockwork or a changing of the guard pretty much. As the sun started to set, started to become dusk and a little bit dark, the male will come up and approach the female who's sitting on the eggs. They do their little calls. They kind of stand around a bit. The female jumps up and off the eggs and then the male comes in and sits down and then the same thing happens again at dawn.
Kirsty: Kristal and her team's research was one of the first of its kind. These types of calls haven't been recorded in any shorebirds in Australia.
Kristal: I was just trying to find out, "When do these calls occur possibly why do they occur?". And I found that the calls from chicks within the eggs for Red-capped Plovers actually begins up to five days before hatching. And then for another resident shorebird species, the Masked Lapwing, they actually begin up to seven days before hatching. And so for a little bit of context for both of these species, their incubation time, so the total time that they'll be generally sitting on these eggs before hatching is around one month. It seems in that late stage of incubation, perhaps up to one week before hatching occurs, it's going to be this what we deem the vocalization period. So it's when these chicks are likely to start calling. And we seem to think that these calls are used as a type of communication with parents. So we found that these calls will the structure of these calls actually change with temperature? So perhaps as the temperature cools and the incubation temperatures actually decrease and they're not within this optimal temperature range, perhaps they're then going, "Hey, Mum! Hey, Dad! I'm dropping in temp! Can you please sit on me and warm me up?". Or perhaps it's the opposite, "I'm too hot! Hop off for a little bit or cool me down, please!". It also seems like they may act like an indication that these chicks within these eggs are hatching soon. And the parents may change their behaviour and start to get ready to look after chicks with Red-capped Plovers and with Masked Lapwings. Once these chicks hatch within the hour, they're up and running and they're feeding for themselves. So they go from sitting quietly on eggs to suddenly having up to four chicks running around and having to control them. So they have to prepare for it. Essentially, I found that in the case of Red-capped Plovers, when these embryonic calls were present, the parents actually increased the intensity of their defensive behaviours. So that's kind of what gave us an indication that perhaps these calls are acting as an indicator for hatching because the parents are suddenly going, "Alright, these eggs are viable. They're going to hatch soon, so I'm going to put in all effort that I can to try and keep them alive. So then I'll have my offspring (my kids, essentially)". And then allow them to get to that hatching stage and not be unfortunately nicked by a luring predator or something like that.
Kirsty: Humans change their vocalisations as they grow older. Kristal discovered that the calls of Red-capped Plover chicks change over time as well, from squeaking inside the egg to hatching to being juveniles to being adults. There is still so much to learn about birds. But one thing we do know is that we need to be mindful about where we work when we are birdwatching.
Kristal: If you do like to walk your dog by the beach, make sure to keep it on a leash or under effective control. Be mindful of where you're walking during the spring and summer seasons when there may be breeding birds. Perhaps don't walk up in the upper section of the beach or within the dunes because that's where they tend to lay their eggs. And the reason for that is because it's out of the way of the water, which may be the reason why you might be walking up there as well. So it's always good to just be aware of your surroundings. And I know with another species of plover as well, the Hooded Plover along some of the beaches, at least in Victoria and South Australia, they actually have signs put up to let us know if there's a nest nearby or if there may be a nest nearby. And they'll actually fence off areas of the beach as well. So please take note of those and obey what we are asking you to do.
Kirsty: Kristal has been birdwatching and bird sciencing (yes, that's a new verb that I just made up) for many years. Here is her advice about watching shorebirds like Red-capped Plovers.
Kristal: Well, I'm sure this kind of advice is what you might get for just birdwatching in general. These are wild birds. Most of the time they're not really used to human interaction, so they're pretty flighty. You probably won't be able to get too close, but I suppose the key is to be persistent. So pick a spot where you're comfortable, plunk yourself down. I like to kind of lay up in the dune somewhere and just have my binos (my binoculars) next to me and then just wait for the birds to come to you. With shorebirds, they're generally feeding most of the time so they'll be along the water's edge running around and feeding along with the waves. If they're not there, they might be sitting in a big group. So they'll probably be roosting, which is essentially just means they're all sitting together in a big group. You might be able to see them as well there. And if you don't want to go out by yourself, there's always birdwatching groups that you can join or there's things like BirdLife Australia or the Victorian Wader to Study Group and they're always more than happy to have new people join and to tag along because really they just want to share their knowledge as well. So they're a great group of people to go out with and you'll learn a heap by joining along with some of these different groups as well.
Kirsty: Kristal recommends two great guides for identifying and finding out about shorebirds. I've listed the resources in the episode notes for you.
Kristal: The first one is a Shorebird Identification Booklet that was written and created by BirdLife Australia. I think I was given this back when I was starting to look at shorebirds and I was trying to identify the different species that they are because unfortunately a lot of shorebirds actually look pretty similar, particularly the migratory species. They come down here and they're in what we call the non-breeding plumage. So generally with some of these species, they'll actually have different colorations in their feathers when they're breeding and when they're not breeding. And so when they come down here for their non breeding season, they all kind of look the same. So this little booklet has some really great diagrams and some great information and it's really quite small and compact, so I still hold it on me every time I'm out in the field. Actually, I keep it in my car and I keep my binoculars in my car too. So whenever I'm perhaps near a beach and I see something, I can always whip it out. I can always whip my binoculars out as well. So I'm always ready to go and ready to identify something.
Kristal: The second one that I've listed is actually an app for your phone. So it's a Field Guide to Victorian Fauna and it's created by Museums Victoria. This is a really handy app that kind of gives you the most common species for Victoria. And it's not just birds, but it gives you pretty much everything from invertebrates to a range of different marine species and some your mammals as well. There's actually one available for, I believe, each state in Australia as well. I don't think you need the Internet to access it actually, which is really handy as well when you're somewhere out in the bush and you don't have reception, you can always access them. And with this particular app, they use photos as well so the coloration is always going to be spot on. And for some species of birds as well, they actually have some calls. So that's come in handy quite a few times as well.
Kirsty: I also recommend BirdLife's ‘The Shorebirds Winged Thing’ educational brochure. It's designed for kids, but personally I found it really helpful as a beginner birdwatcher. I hope you enjoyed learning about shorebirds and Red-capped Plovers as much as I did. Many thanks to Kristal Kostoglou for taking the time to chat with us. You can connect with Kristal and the rest of the Weekend Birder community on your favorite social media platform. Our handle is @birderpod and you can also find the links on our website at weekendbirder.com.
