The Science of Birds - Kingfishers

Episode Date: January 10, 2021

Kingfishers—all the birds in the family Alcedinidae—are the focus of this episode. There are many species of these charismatic birds living across the world.Learn about their key features, global distribution, evolution, feeding, and more.~~ Leave me a review using Podchaser ~~Links of InterestSlow-motion video of diving kingfisher 1Video of Pied Kingfisher huntingHow a kingfisher helped reshape Japan's bullet trainLink to this episode on the Science of Birds websiteSupport the show

Kingfishers. Those little bluish birds that go splush into the water to catch tiny fish. I'm guessing you've seen one of those slow-motion videos that shows a kingfisher from an underwater perspective, from the fish's perspective, as the bird plunges below the surface. It's an incredible thing to see. Most of us have a good sense of what a kingfisher looks like. The numerous kingfisher species around the world share the same basic body shape and silhouette. So these birds are pretty recognizable. The body is stout and ovoid, or in other words, egg-shaped. The head and bill seem a couple sizes too large, like a kid's drawing where the proportions are way off. Oh wow, Timmy, you're such a good artist. Is that, is, is that supposed to be a bird? Uh, good job, buddy. Hey, but you drew the head a little

too big, don't you think? Then Timmy cries and runs out of the room. But seriously, one time I did an illustration of a kingfisher, and I was really careful to get the proportions just right, using reference photos and all that. But when I looked at my finished drawing, the bird's head looked comically oversized. But that's just how it is, for real. As with many types of bird, the bill of the kingfisher is one of its defining features. It's massive, straight, and sharply pointed. It's spear-shaped. In quite a few kingfisher species, the lower part of the bill, the lower mandible, curves upward to meet the relatively straight upper mandible. So with these spear-shaped bills, you'd think that kingfishers would spear their prey, right?

But nope. They don't pierce fish or other prey with their beak. A kingfisher actually opens its beak up in the instant before impact, using it more like tongs than a spear. But I've seen multiple sources online saying that kingfishers spear their prey, sources like a web page with fun facts about kingfishers for kids. This is pretty lame because instead of fun facts, kids are being told fun lies about birds. Fake news. As for what kingfishers eat, the name says it all. Or does. it? Hello and welcome.

This is the Science of Birds. I am your host, Ivan Philipson. The Science of Birds podcast is a lighthearted, guided exploration of bird biology for lifelong learners. This episode is all about kingfishers. Not just one species, but the whole mess of them. the more than 100 species in the biological family, Alcadinity. Kingfishers have much to teach us,

so let's stop sitting and waiting around and dive in already. The most familiar kingfisher species in North America and Europe are indeed specialists that eat mostly fish. and they do so in spectacular fashion. So they get a lot of attention and admiration for their fishing skills. But what about the many other kingfisher species? It turns out that more than half of them are not fish eating specialists. Fish eaters are actually in the minority.

Depending on which kingfish or species you're talking about, its diet might be mostly insects, lizards, earthworms, or another type of creepy crawley. We'll talk about how kingfishers hunt for prey in a few minutes. These are mostly smallish birds. They're generally quite a bit smaller than a crow, but larger than a house sparrow. However, the smallest species is the African dwarf kingfisher, which is only 10 centimeters long. That's four inches.

Remember that the length of a bird is measured from the tip of the bill to the tip of the tail. So at 10 centimeters long, the African dwarf kingfisher is a teeny tiny bird. The largest species is the aptly named Giant Kingfisher, also found on the African continent. It has a great scientific name, Megasurili Maxima. This bird is about the size of a crow, approximately 44 centimeters or 17 inches long. The giant kingfisher looks like an incredible Hulk version of a bird. its cousin, the belted kingfisher, which is our familiar species in the U.S. The cuckaburas of Australia and New Guinea are actually kingfishers, in case you didn't know.

The famous laughing cuckaburah is the world's heaviest kingfisher species, with females weighing an average of 352 grams, which is 12.4 ounces. To accentuate their giant bobbleheads and oversized bills, kingfishers have stubby feet and short, squared-off tails. They're among the few types of bird that have syndactyl toes, that's spelled S-Y-N-D-A-C-T-Y-L, syndactyl. This means that of the three toes that face forward on the foot,

the outer and middle toes are fused together for most of their length. Syndactyl translates as together fingers. Humans are sometimes born with syndactylie. where some fingers or toes are fused. In kingfishers, the syndactal toe arrangement increases the surface area of the sole of the foot, so it probably improves the bird's grip while perching. I said that kingfishers have short tails, and that's true for the vast majority of species. But there are nine species in the genus Tanisiptera that just can't play by the rules.

These are the Paradise Kingfishers. The central pair of tail feathers on these birds are long, elegant, and colorful, some combination of blue and white. Unlike what we see in birds like peacocks and wild turkeys, the fancy tail feathers of paradise kingfishers aren't found on only the male. Both sexes have them. Why, you ask, why do they have such glorious tail streamers? Good question.

The evolutionary process of sexual selection is probably a bit of, work here. But I haven't turned up any research that confirms this specifically for these long-tailed kingfishers. Similarity between males and females is the general rule in kingfishers. You usually can't tell them apart by just looking at them. Some exceptions include the giant kingfisher and the handful of species in the western hemisphere. These birds show some sexual dimorphism, where males and females look different. But get this. In their efforts to blow your mind, these kingfishers flip the script so that it's the female who shows more color than the male. The female belted kingfisher, for example, has a rust-colored band across her lower breast.

The male doesn't have this jazzy accessory. He has to make do with his simple blue and white plumage. And speaking of plumage colors, oh boy, kingfishers are, as a group, a brightly colored lot. I just looked at illustrations of all the world's Kingfisher species and, wow, my retinas are still burning with the after images. It was all a bunch of brilliant blue, orange, turquoise, hot pink, white, and green. Many species have orange bills that I would describe as neon or day glow. They're unreal. I'll put some photos in the show notes to highlight some colorful species.

Interestingly, the gorgeous blue, turquoise, cyan, and green shades of Kingfisher feathers don't come from any pigments. Most vertebrates aren't able to produce pigments in this color range. At the microscopic level, the seemingly colored parts of blue feathers on kingfishers are actually just gray or translucent. The blues we see come from the way white light interacts with the most of the most of the microscopic structures of the keratin proteins in feathers. Blue wavelengths get scattered by the feathers,

while other wavelengths just pass through or get absorbed. This is a form of what's called structural color. Specifically, this is an example of the Tyndall effect. That's T-Y-N-D-A-L-L. The Tindle effect is what causes smoke from a motorcycle tailpipe to look bluish, and it's where blue eye color comes from in humans. Blue-eyed people don't have any blue pigment in their eyes. It's just a natural magic trick,

a trick of the light scattering off of microscopic structures in the iris. Nido. Moving on to the sounds that Kingfisher's make. These birds aren't known for singing pretty songs, but that's okay. They do make some fun sounds, so let's have a listen to a few of them now. The belted kingfisher, common across North America, makes what is described as a harsh, uneven

rattle. Here's the sound of several belted kingfishers chasing each other around while rattling away. I love the sound of that bird. I get a little rush of dopamine in my brain every time. I hear the rattle of a belted kingfisher. I just love those little dudes. Across the pond in Europe and Asia, the common kingfisher is a similarly well-known bird. It has a softer, whistle-like call. For a more dramatic sound, here's the song of a green-backed kingfisher on the island of Sulawesi in Indonesia. Pretty haunting, huh? Well, that's it. Those are all the interesting sounds made by kingfishers.

Ah, I'm just jerking your chain. There are loads of other great sounds made by these charming birds. But there's one Kingfisher vocalization that would be criminal to skip over. Are you ready? Here we go. Here's the amazing laughing cuckabura from Australia. I mentioned earlier that there are a bunch of different kingfisher species. Well, how many species are there? The family Alcadinnati is made up of all the world's kingfishers and cucoburas.

At last count, there are between 114 and 120 species. 118 is the official number on Clements checklist, which is what Ebert uses. So there's a fair amount of species diversity within the family Alcadinity. These 118 species are divided into three major genetic lineages. Each lineage represents a unique subfamily. The unofficial names of these sub-families are the Pygmy Kingfisher's, the Forest Kingfisher's, and the Water Kingfisher's. The forest kingfisher subfamily, technically named Halcyonni, has the most species, about 70. The Cucoburras and Paradise Kingfishers are in this subfamily.

The water kingfisher subfamily is called Cyrillany. It has the lowest diversity of the three subfamilies, with only nine species. The belted kingfisher and giant kingfisher are in this group. So are the other five Western Hemisphere species, and the Pied Kingfisher, which is widely distributed across sub-Saharan Africa and Southern Asia. And then you got your pygmy kingfishers. Now let's not forget about those little buggers. As I've pointed out before, anything with the word pygmy in its name is guaranteed to be absurdly cute.

Not only are these birds cute, they're among the most brightly colored kingfishers. The scientific name of the Pygmy Kingfisher subfamily is Alcedinini. They're also called river kingfishers. There are about 35 species in this subfamily. The common kingfisher, Alcetto at this is one of them. Of course, in Europe they just call this bird the kingfisher. People in Europe seem to think they don't need to use qualifiers like common or Eurasian. No, sir.

As far as Europeans are concerned, they have all. the OG archetypal birds and other animals. So to them, it's not the Eurasian ren, it's just ren, troglodytis troglodytes. That's the other thing. The genus and species names are often the same word like that. So the Eurasian magpie is just magpie to people living in Europe, with the scientific name PICA Pika. The European toad is just toad, and its scientific name is Bufo Bufo. Shall I go on? No, I shall not. I just think this is funny. It's an artifact of when and where the first scientific names were assigned. The Swedish naturalist Linnaeus and his buddies are to blame. But hey, if you live in the UK or Europe, let me know if I'm wrong. Maybe you guys

use the full names of your birds and other critters more than I think you do. All right, back to Kingfisher's. So we've got three sub-families. These three major, lineages within the family, Al-Sahdinity. Even though birds in these sub-families all look roughly similar to us silly humans, the three lineages have been genetically distinct for millions of years. The closer you look, the more differences you would probably find among the forest kingfishers, the water kingfishers, and those adorable pygmy kingfishers. Now let's say you have an irrational fear of kingfishers.

you've decided to move to a place where you'll never again have to come across one of these terrifying, small-bodied, big-headed creatures with their stabby-stabby beaks. Where could you go? Well, unfortunately for you, your options are limited. To avoid all contact with kingfishers, you'd need to live in the Sahara Desert, the Arctic, or, you know what I'm going to say, even though it goes without saying, Antarctica. Kingfishers are all over the planet, for the most part, so that makes this a cosmopolitan family. The same is true of Anatidae, the family of ducks and geese, which I covered in episode 18 of the podcast.

A cosmopolitan species or family or whatever is found across all or most of the earth. Kingfisher species are not, however, evenly distributed around the planet. most of their diversity is in the old world. Only six species live in the new world, in the Americas. And we find more kingfisher species concentrated in the tropical latitudes than in the temperate areas. North of Mexico, we have pretty much just one species, the belted kingfisher. Northern Europe and Asia have the common kingfisher and a few more species in the Far East. Given their cosmopolitan distribution, it's perhaps not surprising that kingfishers live in lots

of different habitats around the world. Yes, many species do hang out near water. Some kingfishers hang out at the edges of lakes and ponds, others prefer rivers and streams. Some live exclusively in mangrove forests along the coast, some live on tiny coral atolls in the middle of the ocean. But there are also a bunch of species that aren't particularly interested in large bodies of water. The many species in the forest kingfishers subfamily, for example, live mostly in tropical forests or open woodlands. Other kingfishers live up in the mountains or in the desert. The best-known desert lover is probably the red-backed kingfisher of Australia, Todorampus peripigius. This little bird lives all across the Australian continent,

but it seems to prefer the super-dry habitats of the interior. Most kingfishers live in more or less the same place all year. Our familiar, belted and common kingfishers, however, are among those that migrate. Populations of these northern species retreat southward from regions that freeze up in the winter. Now, let's take a brief look at the evolutionary history of the world. of kingfishers. I say brief because that's me telling myself not to nerd out too much on the evolutionary biology stuff. That's my jam. I love evolution. I love thinking about birds in the greater context of geological time and global geography. But we don't have all day here, do we?

So here I go. You can do this, Ivan. Keep it brief. The first question is, How long has the planet been blessed by the presence of these awesome birds, these fisher kings? Two recent research papers on the evolution of kingfishers and their close relatives shed a lot of light on this question. Ornithologists based at the University of New Mexico conducted both studies. The researchers used genetic data to build phylogenies, also called evolutionary trees. They built a tree for the Kingfisher family in the first paper and another tree for kingfishers plus their close relatives in the more recent paper. Using a bit of fossil data and some complicated statistics,

the researchers were able to calibrate their evolutionary trees in time. This allowed them to estimate when and also where Kingfishers first came on the scene, way back in the day. From this research, it looks like, these birds originated in southern Asia, in India or Malaysia, sometime between 20 and 34 million years ago. At that time, they would have split away from their closest relatives, the Mott Mott Mott's. Mot Mots, just saying that word makes me laugh. Mott Mott Mots are also colorful sit-and-weight predators. They live exclusively in the New World tropics.

From Southern Asia, Kingfisher's diversified and spread around the world in multiple waves of colonization. Along the way, the three sub-families formed and diverged. A lot of the species diversity we see today among Kingfishers is the result of relatively recent evolution. This brings us to birds in the genus Sakes and birds in the genus Todirampus. These genera contain 25 and 30 species respectively. Genera is the plural form of genus. These two diverse genera contain nearly 50% of all Kingfisher species. Birds in the genus Sakes, that's spelled C-E-Y-X.

Birds in this genus are in the Pygmy Kingfisher subfamily. Kingfishers in the genus Tota Rampus are in the forest kingfisher subfamily. Why are these two genera so rich in species? What's the deal? The deal has to do with tropical islands. In the last few million years, these little buggers have been colonizing one island after another, forming new species all along the way. Islands are, in general, hotbeds of evolution, where new species form more often than on the mainland.

This is mostly because of the geographic isolation. of islands. You know, like the Galapagos Islands, Darwin's finches, all that good stuff. Kingfishers in the genus Sakes have been forming new species across the Philippines and the islands of Indonesia. Similarly, Toder Ramfus kingfishers have been island hopping across the Pacific, across Oceania. They've been forming new species all over the place, from Fiji to New Zealand to French Polynesia. Many of these species exist on only one small island. All right, we've taken our brief look at the evolution of kingfishers, as well as their global distribution and diversity. Now let's get into how these birds are doing from a

conservation perspective. But first, I'm going to take a quick slurp of some coffee. And I have a favor to ask of you. If you're enjoying the Science of Birds podcast, if you learn some stuff here, get an occasional laugh out of it, whatever, I'd be delighted to get a review from you. If you're listening on Apple Podcasts, you can leave a review in your app.

If you're listening on Spotify or somewhere else, a great place to leave me a review is at podchaser.com. Podchaser is a free resource for people who love podcasts. I'll put a link in the show notes to the page where you can leave a review. If you're new to Podchaser, you'll need to create an account first, but it's quick and easy. Reviews really help me reach more people who want to learn about birds. So I hope you can take a moment to do that. Now let's get back to those glorious kingfishers.

Let's talk about conservation issues with kingfishers. I wish I could say that there are no such issues. We could just skip ahead to talking about how kingfishers hunt and make babies and all that. But unfortunately, at least 43 of the 118 kingfisher species are in definite trouble. So that's over one-third of all the species. According to the IUCN red list of threatened species, there are four critically endangered kingfishers, as well as two that are endangered. This is at the global level.

And then we have 10 species that are in the vulnerable category and another 26 that are considered near-threatened. Now, we've talked about how much of the world's Kingfisher species diversity is strewn across a bunch of islands, in the Philippines, Indonesia, and the Western Pacific Ocean. And you know that birds and other critters on islands tend to get hammered by human shenanigans, right? Animals on islands are extra vulnerable

to habitat destruction, hunting, and the ravages of invasive species. So, putting all this together, you can predict where most of our endangered kingfishers are. That's right, on islands. In our list of how many kingfishers are in trouble, I didn't mention the one species that's in the most dire situation. The Guam kingfisher, Todiramphus, Cinema Minus, once lived on only its namesake island.

Guam is a small isolated island north of New Guinea and east of the Philippines. Brown tree snakes were accidentally introduced to Guam not long after World War II. In the following decades, this invasive snake was responsible for wiping out many of Guam's native bird species. By the mid-1980s, the Guam kingfisher was almost extinct. The last 29 kingfishers were caught and taken into a captive breeding program to save the species. So today, the Guam kingfisher is one of only a handful of bird species in the world with the sad distinction of being extinct in the wild. There are around only 200 Guam kingfishers at a couple breeding facilities in Guam,

and in the mainland U.S. Conservationists plan to reintroduce them at some point, but the brown tree snake and feral cats are still a major threat. We can all hope that somehow, someday, this bird will thrive in the wild again. Most of the cruel stuff about kingfishers has to do with how they eat. So it's time to get more into all of that. Kingfishers are mostly what we call sit and wait predators. They sit on a branch and wait until they spot something moving below,

either in the water or on the ground. Maybe it's a juicy fish, an insect, or a small reptile. It varies from species to species, but kingfishers eat all kinds of other stuff too, like crabs, amphibians, mollusks, and even baby birds in the world. small mammals. To maintain their high metabolisms, kingfishers scarf down a lot of these other critters, 50 to 60 percent or more of their body weight every day. Having zeroed in on its prey, a kingfisher darts down to nab its meal using its massive bill, again not like a spear but like a pair of tongs. Most species have small bodies, short tails, and rounded wings. These features

allow a kingfisher to accelerate quickly from its perch to reach its target in a flash. Some kingfishers can hover in the air while hunting, rather than sitting on a perch. The most famous hoverer is the pied kingfisher, Surrilli Rudis. I mentioned that this bird lives in Africa and southern Asia. The pied kingfisher is the largest bird in the world that is capable of sustained hovering. It's about 27 centimeters or 10.5 inches long. The Pied Kingfisher hunts over large bodies of water, like lakes and lagoons, far from any branches to perch on.

While hovering, it peers down into the water looking for fish. It keeps its head amazingly stable while the rest of its body moves around with each wing beat. What plumage pattern do you expect a Pied kingfisher to have based on its name? Pied, P-I-E-D, usually refers to a black and white all-over sort of coloration in birds and other animals. We've got the Pied Heron, the Pied Thrush, Pied Cormorant, and so on. The Pied Kingfisher is indeed black and white. And maybe we should call killer whales Pied whales, because that sounds a lot more friendly, don't you think? one of the take-home fun facts of this episode, I think, is that only a minority of

kingfisher species actually specialize in eating fish. I pointed this out earlier. So if you want to make new friends at a cocktail party, just walk up to a stranger and say, excuse me, but did you know that most kingfishers don't actually eat fish? And just like that, you'll have a new BFF. Two large eyes fill most of the space in the large skull of a kingfisher. The vision of these birds is pretty spectacular. It would have to be, right, given their ability to catch skittish, fast-moving prey like small fish. Most other types of birds have eyes that only face outward to the sides, such that they have only monocular vision. But some birds like hawks, hummingbirds, turns, and kingfishers have.

binocular vision as well. This is where both eyes see at least part of the same image, providing more accurate depth perception than monocular vision. Kingfishers have a narrow band of binocular vision straight ahead, aligned with their bill. When hunting, a kingfisher first uses its monocular vision to detect the movement of any small critters. Then it switches to binocular vision as it swoops down to dive-bomb its prey. There's some more interesting stuff about the anatomy of Kingfisher eyes. This has to do with the fovea. You may know about this because this structure is also in the human eye.

The phobia is a tiny dimple, a depression in the middle of the retina. It's the spot where we get our sharpest vision. This is because the phobia is densely packed with color-sensitive, cone cells. Some birds, like our little kingfisher buddies, have not just one fovea in each eye, but two. Each eye has two phobiee. One of them provides sharp eyesight for the bird as it looks out to its sides, with monocular vision. This is the standard situation for bird eyes in general. The second phobia in the kingfisher eye is positioned further back on the retina. It allows for acuity while the bird is in its binocular mode, as it rockets down toward its targeted prey.

The lens in the eye of plunge-diving kingfishers has a special shape that allows these birds to focus their vision underwater. Most birds can't do that. And kingfishers have built-in swim goggles, too. All birds have a third eyelid called a nictitating membrane. It slides across the eye horizontally. When a kingfisher plunges into water, its nictitating membranes cover its eyes. And since the membranes are transparent in kingfishers,

the bird can still see. I'll put a couple links in the show notes to slow motion videos of kingfishers diving. See if you can notice the nictitating membranes on the bird's eyes, and also watch how the beak opens up to nab the fish. The beaks of kingfishers are pretty special, not just because they're ginormous or because, at least in some species, they're a blinding shade of orange.

Kingfisher bills are superbly adapted tools for catching prey. The bill of the classic plunge diving fish-eating kingfisher has a special streamlined shape. It's great for efficiently piercing the water's surface at high speed. There's a really fun research study on Kingfisher Bills conducted not that long ago by a graduate student at Bangor University in Wales. His name is Rowan Howl. He used 3D imaging to scan the bills of eight kingfisher species. Half of these were diving fish specialists

and the other half were terrestrial. After being scanned into a computer, the bills were 3D printed to make plastic models of each. How, the graduate student, set up an apparatus to plunge each plastic model into water to accurately measure the deceleration of each kingfisher's bill. Lo and behold, he found significant evidence that the bills of fish-eating specialists cause much less deceleration on impact. This tells us that the bill shapes of these species are indeed well adapted to their special mode of feeding.

These bills pierce the water in such a way that they minimize the force of the impact. 3D-printed Kingfisher beaks. What a cool research project. Kingfisher bills have also inspired the shape of a train. A train, you say? That's preposterous. Trains don't plunge into the water. Well, not unless something has gone horribly wrong anyway. But it's true, though. Some models of Japanese Shinkansen bullet trains have a sci-fi-looking, pointy front end. You see, back in the day, when these trains had the more standard bullet-shaped nose up front, they would make a deafening boom sound as they exited tunnels.

The train produced a shockwave by pushing air at high speed through the tunnel. This was a problem. It bothered people in wildlife. An engineer, who also happened to be a birdwatcher, was inspired by the bill of the kingfisher to design a more elongated, streamlined front end on his trains. And it worked. The bird-beaked trains didn't make the loud booms. These trains are also faster and more fuel-efficient. This is a splendid example of what's known as biomimicry.

engineers can borrow designs from nature to solve human problems. Over millions of years, evolution has honed the shapes of bird beaks for specific purposes. Sometimes we don't need to reinvent the wheel. We can just copy the wheel's blueprints from our friends, the birds. And speaking of friends, some research on the common kingfisher in Spain has shown that these little birds like to buddy up with Eurasian otters. But I suppose you European folks would just call them otters. And surprise, surprise, the scientific name of this otter species is Lutra, Lutra.

Anyway, otters also eat fish. Kingfishers follow otters around so they can either snatch up the fishy scraps left behind by the playful mammals or nab any little fish disturbed by all the furry activity. The kingfishers benefit from the behavior of the otters, and the otters aren't bothered by the birds. That's good because nobody wants to bother an otter. This arrangement between kingfishers and otters is thought to be an example of what ecologists call commensalism. Commensalism is an association between two species, where one of them benefits and the other is unaffected. Apparently, this commensalism between kingfishers and otters occurs in other parts of the world, too, with different species.

Pretty cool and pretty cute, if you ask me. After a kingfisher successfully grabs prey, it usually flies to a perch to eat. It's common for the bird to take its fish or other unfortunate prey animal and smack it hard against the tree branch, repeatedly. This is probably to stun the prey and to break off any spines or maybe to break some bones. Kingfishers swallow their prey whole, so this tenderizing process makes everything go down a little smoother. Sort of like owls, kingfishers often hack up a pellet after digesting their meal. This pellet contains any hard bits like bone fragments, scales, or shells. Before we move on to talk about breeding in Kingfisher's, I want to introduce a new segment to the podcast.

When we learn about a family of birds, as we are today with Al-Sadinidae, we sometimes come across members of the family that really stand out. These species are outliers that, for one reason or another, seem kind of weird. So I give you the first ever weirdo alert on the podcast. Weirdo alert, weirdo alert. Our weirdo bird today is the shovel-billed kookabura, also called the shovel-billed kingfisher. Its scientific name is Clyto-Sakes Rex. The shovel-billed kookabura lives in the rainforests of New Guinea. It's a medium-sized kingfisher, with plumage that's orange and brown with a splash of blue.

on the rump. What sets this species apart is its bill. This is relatively short but thick and deeply arched. So not your typical elongated kingfisher bill. The shovel-billed cuckabur also forages in a weird way compared to other members of its family. It usually forages on the forest floor rather than from a perch. And ornithologists think this bird might be more active at night than in the day. Also weird. That chunky bill isn't just for show. The shovel-billed kookabura literally shovels its way through patches of soil as it hunts for earthworms. It routinely plows a patch of about 20 centimeters by 30 centimeters, down to 8 centimeters deep. It eats other small animals too, but worms seem to be its favorite thing. Shovel-billed kingfishers

usually have bits of mud caked on the insides and outsides of their beaks. Fantastic. What a weird and wonderful bird. To keep up with the world's insatiable demand for kingfishers, male and female birds dutifully pair up to reproduce. Kingfishers are monogamous. Depending on the species, a pair may stay together for only one season

or for their entire lives. The belted kingfisher is one example of a seasonally monogamous species. The laughing cuckaburah is a species that mates for life. These cuckaburas are also cooperative breeders. Often, four or five of a mated pair's older offspring will hang around to help defend mom and dad's territory. These younger birds also help incubate the eggs and feed the nestlings. Territoriality is the norm for kingfishers.

They fiercely defend their stretch of a river or their patch of forest. The food resources and nesting habitat in their territory need to be protected from other members of the same species. All members of the family Alcadignity are cavity nesters. Most of them dig tunnels to make their nests. They dig tunnels in riverbanks or similarly exposed air. areas of soil, like road cuts or ditches. Other kingfisher species nest in tree cavities.

Amazingly, there are also species that make their nests by digging holes into the nests of tree-dwelling termites. These arboreal termite nests are big masses made of cemented termite poop and bits of wood. The termites don't really do much to defend their colony against this avian invasion. A study that investigated nests of the Micronesian Kingfisher found termites crawling around in freshly excavated kingfisher cavities. But then the termites were never seen in there again. Maybe the termites just seal themselves up in their own little tunnels,

leaving the birds to their business. Also, I have a new word to add to your vocabulary, termitarium. That's the technical name for a termite nest, termitarium. or termitaria in the plural case. Aquarium, planetarium, herbarium, termitarium. Come on, kids, get in the car. We're going to the termitarium!

When kingfishers excavate a nest tunnel, both sexes put in a lot of work. They use their bills at first, and once they can scramble around inside, they also use their feet. On riverbanks and other such places, the male and female often take turns flying fast and furious at the slope, ramming it with their bills. They use their bills like a pickaxe during this aerial ramming phase. Sometimes these little birds ram the surface so hard that they crack their bills, or even get fatally injured, crazy.

After several days or even several weeks, the birds finish digging their tunnel. They make a small chamber at the end where the eggs are laid. The belted kingfisher and the common kingfisher dig tunnels somewhere around 3 to 6 feet or 1 to 2 meters deep. But the longest tunnel on record for a kingfisher was made by, surprise, surprise, a giant kingfisher. Good old mega-serrilli maxima. The tunnel was about 28 feet deep, which is about 8.5 meters. This makes me think of dig-dug, that old arcade game from the early 80s. Anyone remember Dig-Dug?

You play a little guy digging tunnels all over the place. Now I want to make a nature documentary about Kingfishers digging their nest tunnels. But the background music and sound effects will be from the Dig-Dug video game. Baby Kingfishers are cared for by both mom and dad. At least in the fish-eating kingfishers, the nest chambers can become littered with all sorts of gross fish bones, scales, and other flotsam. It probably doesn't smell too nice up in there. Once the young birds have emerged from the nest and have fledged, the parents teach them how to

catch prey. Mom and dad will toss a dead or stunned fish or other food item into the view of the youngsters. They do this training exercise at least a few times. In most species, the family splits up after one to four months together. The newly fledged kingfishers are off on their own. Life is hard for these young, relatively naive birds. Many don't survive their first few weeks being on their own. And kingfishers in general, including adults,

have at best about a 50% chance of surviving from one year to the next. So even though there's a record of a common kingfisher that lived to be 21 years old, most don't live more than maybe four years. So it goes. I'm guessing that even before pressing play on this podcast episode, you thought Kingfisher's are pretty red. Because they really are, aren't they? But I hope this episode gave you a deeper understanding. and appreciation of the marvelous birds in the family Alcadinity.

They have many fascinating features and behaviors. Chances are, you live somewhere where kingfishers are lurking about. I encourage you to spend a little extra time observing and admiring the next kingfisher you come across, if you can. And I'll do the same. There's a lot we can still learn about these big-headed, syndactal toad, dive-bombing, tunnel-digging, train-inspiring birds. Thank you so very much for listening, for your attention, and for your interest in learning

about birds and our wonderful world. If you haven't already subscribed to the Science of Birds podcast, I hope you'll do that and keep coming back for more exciting bird learning. If you have thoughts or feelings about the show, shoot me an email. The address is Ivan at Scienceofbirds.com. You can check out the show notes for this episode, which is number 20, on the Science of Birds website,

scienceofbirds.com. This is Ivan Philipson. Until next time when we shall geek out about birds once more, I say to you, Cheers.