The Science of Birds - Pelicans

Episode Date: November 19, 2020

SummaryPelicans are large, peculiar waterbirds with a unique way of feeding. Using their long bills and throat pouches, they scoop up fish and other prey from water. Some pelican species plunge dive f...rom the air, others work in cooperative groups to improve their chances of fishing success.In this episode, we focus on the family Pelecanidae. We go through the characteristics of pelicans, with a focus on their bill and throat pouch.We also discuss the feeding strategies of pelicans, how they breed, and their evolution.Finally, we touch on some issues about the conservation of pelicans.Along the way, we’ll do some myth-busting. There are several misconceptions about pelicans that we need to address.Links of InterestVideo about the plunge-diving adaptations of Brown PelicansVideo from the BBC about pelicans eating Cape Gannet chicksLink to this episode on the Science of Birds websiteSupport the show

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Starting point is 00:00:00 I love watching a group of brown pelicans fly in formation over the ocean. With their huge wingspans, they glide easily and flap infrequently. As they float down to cruise just inches above the water's surface, they make use of ground effects to increase their flight efficiency. They make it look almost effortless. Their appearance recalls something prehistoric, with their long bills, chunky bodies, and expansive wings. but these brown pelicans are actually small for their kind.
Starting point is 00:00:34 Most other pelican species are three or four times larger. Those guys look even more like something out of the lost world. And when dozens of brown pelicans are diving like torpedoes into the waves to catch fish, wow, what an amazing thing to see. As a kid growing up in Southern California, I sort of took these birds of the coast for granted. I just assumed that all pelican species were peasant. plunge divers like the brown pelican, and that people everywhere got to see this behavior.
Starting point is 00:01:05 I wasn't alone in having misconceptions about pelicans. It turns out that there are several persistent myths about these birds. Maybe you've heard some of them, or dare I say, even fallen victim to believing them. Well, today we're going to get pelicans all sorted out. We're going to shine the light of science on these wonderful animals and learn about their unique anatomy, their behavior, and more. Hello and welcome. This is the Science of Birds. I am your host, Ivan Philipson.
Starting point is 00:01:43 The Science of Birds podcast is a lighthearted, guided exploration of bird biology for lifelong learners. This episode is all about the family Pelicanity, the Pelicans. There is much to discuss about these birds, my friends, so let's take the plunge. Pelicans are large water birds, familiar to people in many parts of the world. Since most pelican species are big, whitish, and oval-shaped, you might mistake one for a swan or goose from a distance. But seen up close a pelican is unmistakable.
Starting point is 00:02:27 Its long bill and throat pouch are dead giveaways. The pouch is made of stretchy, featherless skin. It hangs like a hammock from the lower jaw. This unique feature works like a basket, or really more like a fishing net, that enables a pelican to scoop up fish. No other group of birds feeds quite like this. Those of us who live in North America
Starting point is 00:02:50 are perhaps most familiar with the brown pelican. and its feeding behavior. This species is famous for its dramatic plunge dives. We'll talk about this fascinating behavior in a few minutes, and we'll also go into more detail about the bill and the throat pouch. I'll point out now that while all pelicans make great use of their specialized pouches, the brown pelican is really the only species that has mastered plunge diving. It's the exception rather than the rule. All pelicans have relatively short legs with fully webbed feet. And I mean fully. All four of their toes are connected by webbing. This type of bird foot is called tota palmate, as in like, tally palmate, dude. Duck feet by contrast, and which you may be more
Starting point is 00:03:38 familiar with, have only three toes connected by webbing. That's just plain old palmate. Pelican legs, being stubby, aren't great for walking. But those toto palmate feet make these birds really good swimmers. Given that they eat fish and swim well, it's no surprise that all pelicans spend most of their time on or near water. Some species are coastal, others live mostly on inland waters. In these habitats, they tend to spend time together in groups. Whether in breeding colonies or while out foraging for fish, these are gregarious birds. You can often find dozens of pelicans loitering around on beaches, mudflats, or riverbanks. Such places are called loafing sites.
Starting point is 00:04:27 Seriously, they're called loafing sites or loafing platforms. It's right here in my copy of the ornithologist's dictionary. Loafing sites are places where water birds just hang out in their idle time, to rest, preen, vape, or whatever between bouts of feeding. Most communication between pelicans is visual, rather than based on sound. They lift and wave their wings and snap their bills at each other. Adult birds can make simple calls like grunts and hisses, but most of these are used only within a breeding colony.
Starting point is 00:05:01 In other situations, pelicans are generally silent. So, pelicans are large, they have a distinct bill and throat pouch, they have short legs with toteopalmate feet, they live in aquatic habitats, they're usually social and they don't use their voices much. Okay, let's circle back to talk more about the pelican bill and that snazzy pouch. The beak, the bill of a pelican, is the longest of any bird. Specifically, the Australian pelican is the world record holder.
Starting point is 00:05:42 The male of this species has a bill up to almost 20 inches long, about 50 centimeters. No bird bill is longer. But I'm talking about absolute length, right? If we're looking for the longest bird beak in the world relative to body size, then the trophy goes to the sword-billed hummingbird. The upper bill of a pelican is mostly flat, with a broad, rounded tip. It's not as broad and rounded as the beak of a spoon bill, but it's getting there. I was trying to think of an everyday household object that has the same shape as a pelican's bill,
Starting point is 00:06:18 so I could make that comparison for you. I wasn't having any look, but then I remembered a type of short sword used by the ancient Greeks. It's called a Ziphos, X-I-P-H-O-S. The upper jaw of a pelican looks a lot like a Zipos. So there you go.
Starting point is 00:06:35 What better example of an everyday object than an Iron Age sword wielded by the Spartans? You've got one of those laying around, right? Anyway, another detail is that the Pelicans' sword-like upper bill has a small, hard, hook-like projection at the tip. It's called the nail. The lower jaw, the mandible, is made of long bones that are amazingly flexible. The two halves of the mandible can bow outwards under pressure,
Starting point is 00:07:02 which dramatically enlarges the opening into the throat pouch. More than once, I've come across a brown pelican skull on a remote beach in Baja, California, Mexico. Holding the skull in my hands, I could bend each half of a skull. the mandible like the wood of a sapling tree, like a bow. It was really cool. In the living bird, the distance between the two halves of the mandible is about two inches, five centimeters, in the normal position. When bent outwards, that distance can be over six inches, 15 centimeters. These bones bend passively when the pelican thrusts its open mouth into water, but a pelican also has some ability to actively, voluntarily expand the mandible using its pouch muscles or its jaw muscles.
Starting point is 00:07:50 The technical name for this jaw-bending ability is streptognathism. Streptagnathism. This means twisted jaw in ancient Greek. See, we're back to talking about the ancient Greeks. Pelicans aren't alone in displaying streptognathism, but they give us perhaps the most dramatic example. The remarkable pouch of the pelican dangles below the lower jaw. Its elastic properties come from being infused with a matrix of collagen. It lacks feathers and it's riddled with blood vessels. So we'd say the pouch is highly vascularized. I've been saying throat pouch, but the more technical term is guler pouch. The gular area on a bird or other animal is the upper throat. The word guler shares the same Latin root as gullet. Now we all know how a pelican
Starting point is 00:08:42 uses its guler pouch, right? We just need to remember the old limerick that goes like this. A wonderful bird is the pelican. His beak can hold more than his belly can. He can hold in his beak enough food for a week, but I'll be damned if I can see how the hell he can. While it's true that pelicans are wonderful, and normally limericks are trustworthy sources of scientific information, this limerick, I have to tell you, is mostly fake news. Pelicans do not store food in their guler pouches. This is one of the myths about pelicans, that they hold food in their beaks or their pouches for extended periods of time. It's not a crazy idea, of course, it's fairly reasonable. It's just not what happens. A pelican catches a fish and then swallows it
Starting point is 00:09:30 in short order. This is true even when transporting food to its chicks, pelicans swallow a prey item first, then fly back to the nest to regurgitate the partially digested food for their chicks. In addition to blood vessels, the Guller pouch has sensory nerves running through its stretchy skin. This is helpful for pelicans when they're foraging for fish at night or in murky water. A pelican can feel a fish as it enters its pouch, then it snaps its bill shut. And those blood vessels in the pouch provide an important mechanism for temperature regulation. Being large birds, pelicans can overheat more easily than small birds. By facing away from the sun and fluttering its vascularized pouch,
Starting point is 00:10:17 a pelican can shed heat to cool down. Heat escapes from the bird's capillaries to the surrounding air. This is similar to how the big, floppy ears of elephants work. An elephant is huge, so heat from its metabolism tends to build up in its body, escaping only slowly. The reasons for this have to do with the physics of thermodynamics, which, of course, we don't have time to get into today. You'll just have to trust me.
Starting point is 00:10:43 So heat builds up in the elephant's body, but its ears have large surface areas and lots of blood vessels close to the surface. Just as Guller fluttering dissipates heat in a pelican, an elephant can flap its ears to cool down. The Guler pouch is such an important tool that a pelican takes care to keep its pouch in good working, order. Pelicans have a regimen of stretching exercises to keep their pouches flexible and healthy.
Starting point is 00:11:17 Let's talk about the feeding behaviors of pelicans. The ways these birds use their specialized bills and ghouler pouches to catch their prey are fascinating. All pelican species have more or less the same bill and pouch anatomy, the same basic structure we've been talking about. they share the behavior of thrusting their heads into water to scoop up fish or small animals in their pouches. When catching prey under water, a pelican's guler pouch balloons dramatically with the force of the incoming water. A brown pelican can take in about 2.5 gallons of water in one go, and an Australian pelican can take in about 3.5 gallons or 13 liters. When a pelican is successful, its prey comes rushing in with all that water.
Starting point is 00:12:05 The top of the bill snaps shut and the flexible mandible bones return to their normal position. This closes the opening of the pouch, trapping the prey. The pelican then presses the big water balloon of its pouch against its breast to expel the water through the narrow opening of the bill. With an upward toss of its head, the pelican swallows the prey animal in one big gulp. All of this takes between 15 seconds and maybe a minute or so. Some pelican species have specialized feeding behaviors that elaborate on the basic process we were just talking about. As I mentioned earlier, plunge diving from the air is the brown pelicans area of expertise. This bird feeds on small schooling fish in shallow coastal waters.
Starting point is 00:13:03 While circling in the air over the sea, a brown pelican begins a plunge dive sequence when it spots some fish below. This can start from as high as 65 feet or 20 meters above the water's surface. The pelican dives down head first. It pulls in its neck so that its head sits over its shoulders. It pulls its legs forward and folds its wings back at the wrist. Just before hitting the water, the pelican lines the fish up along its bill, like using the sight on a rifle barrel.
Starting point is 00:13:38 The bird also twists its body to the left at the last moment. Why would it do that? We'll come back to that in a second. Let's continue looking at this dive sequence first. The pelican hits the surface at speeds of up to 40 miles per hour, As its long bill pierces the water, it throws its wings and legs backward while striking forward with its head, like a snake. The movement of the wings and legs here probably gives some extra acceleration to the head.
Starting point is 00:14:08 The Guller Pouch expands and fills instantaneously with water. If our pelican aimed correctly and everything went according to plan, it successfully captures one or more fish in its enormous gullet. Just how often are Brown Pelicans successful at this? Many years ago, my ornithology professor in college told us about a study that addressed this question. The researchers in this study observed Brown Pelicans feeding in Santiago Bay on the tropical west coast of Mexico. Over a couple days, they recorded 2,449 plunge dives.
Starting point is 00:14:47 They calculated that adult pelicans were successful in 84% of the first. of their dives. Immature birds weren't quite as skillful. They came up with a fish only 75% of the time, still not too shabby. I think I remember this study mostly because my ornithology professor said it involved his idea
Starting point is 00:15:07 of the perfect fieldwork. The researchers, he told us, sat on that beautiful beach in Mexico lounging with their toes in the sand. They drank ice-cold beers as they counted pelican after pelican diving into the turquoise waves. As a young college student, I was like,
Starting point is 00:15:24 heck yeah, that sounds awesome. I don't know how much of my professor's story is true about the beer and all that, but I can tell you my own fieldwork as a biologist was never quite that relaxed and idyllic. It was wonderful, don't get me wrong, but yeah, I wasn't drinking beer on a tropical beach. So these pelicans are smashing into the water
Starting point is 00:15:47 again and again day after day. The forces involved could be destructive to the delicate tissues of a bird. But pelicans have been doing this for millions of years. It's no surprise then that they have a suite of adaptations that minimize any negative impacts. How's that for a little wordplay? Looking at these adaptations, we can return now to that whole, I'm a pelican and I rotate my body to the left on impact situation. The best explanation for why brown pelicans twist to the left
Starting point is 00:16:22 is that the birds are protecting the soft tissues of their trachea and esophagus. You see, these structures are always positioned on the right side of a brown pelican's neck. Pretty crazy, huh? Another adaptation that provides protection is a system of air sacs beneath the pelican's skin. These are concentrated on the bird's underside. They act like airbags in a car to cushion the impact. Most birds have air sacks, but these are a bit more specialized for plunge diving. Air sacks and pelicans make them extra buoyant, too, so these birds can't dive very deep.
Starting point is 00:17:01 They float like inflatable pool toys. In your travels, you might have been told by someone that brown pelicans often die of starvation after going blind. They go blind, these people will tell you, because the birds sustain damage to their eyes after so many impacts with the water. If someone tells you this story, you can slap them right in the face because it is false. It's another myth about pelicans, a meme that just won't go away. And, of course, I'm kidding about the slapping.
Starting point is 00:17:32 Violence is not the answer here. Pelicans have been pelicanning for millions of years. If any of them ever went blind from diving too much, well, those guys were likely removed from the gene pool long, long ago. Those guys were more like pelicans. The pelicans that delight us today are the hardened survivors, those that natural selection has endowed with adaptations for their unique feeding strategy. As yet another example of such an adaptation, the third eyelid of the pelican, the nictitating membrane, closes over the eye to protect it at the moment of impact. So if you're going to worry about pelicans, don't worry about them being blinded or otherwise harmed by going about their normal daily routines.
Starting point is 00:18:20 Worry instead about the harm that humans do to them. We'll get to that in a few minutes. I'll put a link in the show notes to a high-quality video about the plunge-diving behavior of brown pelicans. A very different. feeding strategy is used by several of the larger pelican species, including the American white pelican, Australian pelican, and great white pelican. These birds often work together with other members of their species to catch prey. These species rarely, if ever, plunge dive. Instead, they feed while paddling around on the surface of inland waterbodies or shallow
Starting point is 00:19:03 coastal waters. Sometimes they feed alone or with a buddy or two. But at other times, they coordinate their feeding with 10, 50, or even well over 100 other pelicans. In the most impressive displays of coordination, American white pelicans gather in groups of up to 30 birds, forming a semi-circle on the water. They synchronize their bill-dipping movements and herd schools of fish toward the shore or into the center of the circle as it closes in.
Starting point is 00:19:35 These events are called fish drives. They can last up to 10 minutes. or so. These coordinated semi-circles of pelicans have the highest rate of fish capture per bird. That's when compared to pelicans fishing on their own or in less well-organized groups. Pelicans are vulnerable to something called kleptoparasatism. You might have heard of kleptomania, a disorder where a person can't keep themselves from stealing stuff. Cleptoparasite animals are those that steal their lunches from other animals, rather than doing the hard work of catching their own food.
Starting point is 00:20:18 Gulls and turns of several species follow pelicans around and try to steal their catches. A gull sometimes perches on the head of a pelican that has just caught a fish. As the pelican is draining water from its ghouler pouch, the gull tries to snatch the fish. In North America, Hehrman's gull is a particularly notorious klepto. These gulls actually time their migrations to coincide with the movements of brown pelicans. Hehrman's gulls chase pelicans around, harassing them and trying to steal their hard-won catches. But pelicans sometimes flip the script and act as kleptop parasites themselves.
Starting point is 00:21:00 They try to steal snacks from other pelicans or other bird species. For example, the Australian pelican regularly kleptoparasat, cormorants. I'm not sure kleptoparasatizes is a real word, but I'm sticking with it. So far, we've been imagining pelicans as scooping up fish. That's fine because they do indeed eat mostly fish. But pelicans will eat other creatures too. Aquatic critters like crayfish, crabs, turtles, frogs, and salamanders are on the menu for most pelicans. Other birds are eaten too, particularly nestlings of other species. I'll link to a BBC video in the show notes about Great White Pelicans eating Cape Gannet chicks in South Africa.
Starting point is 00:21:54 I'll warn you that, despite the soothing narration by Sir David Attenborough, this video might be upsetting. I mean, poor little Gannets. There are accounts and videos of pelicans eating gulls, ducks, and pigeons. There's also rumor that pelicans have even eaten small dogs. Even though this scenario is plausible, I'm a bit skeptical about it, since I haven't found any solid evidence. So any story about a pelican scarfing down a chihuahua might need to be relegated, at least for now, to the category of urban legend or myth.
Starting point is 00:22:32 When it's time for pelicans to get together to make more pelicans, they often do so in large breeding colonies. Hundreds or thousands of pelicans congregate in places like small rocky islands where they're relatively safe from ground-dwelling predators. Some species nest on the ground, others make stick platforms in trees. The sexes are very similar. During the breeding season, both develop bright colors on the bear skin of their faces and ghouler pouches. American white pelicans also develop prominent horns on their bills. Also called knobs or epidermal plates, these structures are flattened from side to side, sort of like a dolphin's dorsal fin.
Starting point is 00:23:20 These horns are shed after the breeding season. Adults pair off and display their colorful pouches during courtship. Pelicans are monogamous, but only for one season at a time. They find a new mate each year. It's typical for pelicans to lay two to three eggs. These are incubated under the webbed feet of the parents. Both parents care for and feed the chicks. Pelican chicks sometimes show a weird behavior after being fed by their parents.
Starting point is 00:23:50 The chick cries loudly, drags itself around by one wing, and bangs its head on the ground. This can even escalate into convulsions that look like a full-on seizure. Appropriately, this behavior is called a tantrum. Ornithologists don't know why these toddler pelicans act bonkers like this. Maybe it's to monopolize the attention of their parents, perhaps at the expense of their siblings. If I can risk a little anthropomorphizing here, I'd say this sounds a lot like what some human kids do,
Starting point is 00:24:23 and some human adults, if we're being honest. In ye olden days, in medieval times, it was thought that a mother pelican was so dedicated to her attention-hogging babies that she would pierce her own breast to feed them her blood. Not true at all, and no one knows how this conspiracy theory got started. It's yet another myth about pelicans, one that I hope no one still believes. So far, we've covered the bill and pouch of pelicans and how they feed and breed.
Starting point is 00:24:58 Now let's look at their diversity, distribution, and evolution. The Pelican family, Pelicanadee, includes only eight species. We've been talking a lot about the brown pelican and American white pelican. These are species in the new world. The only other species in this hemisphere is the Peruvian pelican. Superficially, it looks a lot like the brown pelican and used to be considered a mere subspecies of the brown pelican. Now it flies proud as a bona fide, full species.
Starting point is 00:25:38 The five remaining species are all in the old world. We have the Australian, Great White, Pink-Backed, Spot-Billed, and Dalmat. Now, before you get excited, no, the Dalmatian pelican is not black and white all over like the 101 Disney dogs. Dalmatian isn't a color pattern. It refers to the historical region in Croatia called Dalmatia. Weirdly, though, Dalmatian pelicans don't seem to be found in the Dalmatian region, at least not these days, according to data from Ebert. I also want to point out that in my Princeton field guide to the birds of Europe, the great white pelican is described as having a comical look. Even better, the Dalmatian pelican is said to have not so friendly a face.
Starting point is 00:26:31 This pelican, you see, he has not so friendly a face. Other than the brown and Peruvian pelicans, which have dark plumage, pelicans are mostly white or light gray. They have black or dark gray flight feathers on their wings. Pelicans are among the heaviest flying birds in the world. Only swans are heavier. Pelicans also have large wingspans stretching to almost 11 feet in the Dalmatian Pelican. That's pretty close to being the world's largest wingspan. The wandering albatross has a slightly larger span at 11.61 feet, or 351 centimeters.
Starting point is 00:27:11 Even though a brown pelican is a big bird, it's actually the smallest of the eight pelican species. This species weighs seven pounds or so. The great white pelican, by comparison, weighs up to almost 30 pounds. As a group, the eight pelican species are distributed across much of the world. You won't find them in Antarctica, but they're on all the other continents. I kind of feel like I need to have a rule or something that on this podcast, it's understood that a bird or group of birds is, by default, assumed to be absent from Antarctica. Unless I tell you otherwise, just assume that the bird we're talking about is not on that continent. That might
Starting point is 00:28:05 save us from having to say every time that such and such birds are found everywhere on the planet, except Antarctica. Anyway, pelicans. They're mostly confined to the tropical and temperate latitudes, and they're absent from the interior of South America and from much of eastern Asia. Pelicans feed and breed around water. The two chocolate-colored species, the brown and Peruvian pelicans, are restricted to the marine environment. They live along shallow, near-shore waters. The other species live mostly around inland waters, wetlands, estuaries, freshwater lakes, alkaline lakes, etc. Now, on to evolution. The oldest pelican fossils date to about 30 million years ago. These were found in France. And here's a neat thing. The oldest of
Starting point is 00:29:01 these fossils is a pelican skull, and it has a beak remarkably similar to those of modern pelicans. So these birds have been scooping up hapless fish and maybe small dogs for over 30 million years. This fossil data, combined with molecular genetic data, paints a fairly clear picture that pelicans originated in the eastern hemisphere. The most likely scenario is that they then spread to the Western hemisphere in a single colonization event. Those pioneering colonist pelicans then evolved into the three new world species we have today. The close relationship of the American white pelican to its New World cousins is counterintuitive. If you were asked to classify the eight pelican species based on appearance,
Starting point is 00:29:49 you'd probably lump the American white pelican with all the old world species and keep the two brownish species in their own group. But, as is often the case, the genetic data tells us the true story and helps us classify species based on their actual evolutionary relationships. Genetic data has also helped us figure out which birds are the closest relatives of the Pelican family. Once upon a time when I was back in that ornithology class, the Pelican family shared the order Pelicaniformis with the frigate birds, gannets, cormorants, and hingas, and tropic birds. So those families were considered the closest relatives of pelicans.
Starting point is 00:30:33 This grouping was based on mostly physical features. For example, these birds all have those fully webbed totipalmate feet. Well, once ornithologists got their hot little hands on some high-quality genetic data, they could get a better picture of the real relationships between pelicans and other bird families. So today, the order pelican of Formes is very different. Those other non-Pelican families have been moved to other orders. They are replaced by the families of ibises, herons, the hammer cop, and the shoebill. The latter two species are actually the closest relatives of pelicans.
Starting point is 00:31:15 Hammercops and shoebills are unique, stork-like water birds living in Africa. See, this is why you got to buy every new edition of your ornobes. mythology textbook. Our classifications of birds and just about every other living thing keep getting rearranged and updated as we get more and more genetic data. This might annoy some people, but I love it. We're getting closer and closer to unraveling the truth. Just the other day, a new study was published in the journal Nature that reported we now have the whole genome sequences of 363 bird species. And importantly, this data set includes representatives of almost every bird family in the world.
Starting point is 00:31:58 The Dalmatian pelican, with its amazing wingspan and not so friendly a face, is currently the only pelican species with a fully sequenced genome. Pelicans face several threats from humans. As is often the case for birds, habitat destruction is high on the list of major problems. Freshwater habitats, which pelicans depend on, are among the most threatened in the world. People routinely drain, pollute, or degrade wetlands in one way or another. You may know that the organic pesticide, DDT, was an enormous threat to bird populations in the middle of the last century. Brown pelicans suffered major losses because DDT and their environments caused the shells of their
Starting point is 00:32:50 eggs to be too thin. A brooding pelican would just crush its thin-shelled eggs. Thankfully, brown pelican populations have rebounded since DDT was banned by most developed countries in the 1970s and 80s. Oil spills can be devastating to pelicans. The horrific Deepwater Horizon event in 2010 caused huge numbers of brown pelicans to be covered in oil. It's uncertain how many of them died.
Starting point is 00:33:20 but at least 612 were cleaned up and released by kind-hearted rescuers. Pelicans in marine and freshwater habitats can run afoul of fishing gear. They get tangled up in old nets or fishing lines and may drown or starve as a result. Fisher people across the ages have persecuted pelicans, killing them outright. Some of them think that the birds compete with them for fish. The Peruvian Pelican and Dalmatian Pelican are both categorized as near-threatened by the International Union for the Conservation of Nature, the IUCN. The Peruvian Pelican depends heavily on vast schools of anchovies off the western coast of South America.
Starting point is 00:34:06 The main reason this bird is in trouble is that humans are overfishing the anchovy populations. The Dalmatian Pelican has lost its wetland habitats in many places, across Eurasia. And this species faces several other threats, such as illegal shooting, disturbance of its nesting colonies, pollution, and collision with power lines. And, of course, climate change looms large as a worldwide threat to pelicans. Their habitats are likely to dry up in some places as droughts become more severe. Warming ocean temperatures may cause fish populations to plummet on the coasts of North and South America. It's hard to what will happen to pelicans as the climate changes. But most of what happens will probably
Starting point is 00:34:51 not be good. You're still with me. I applaud you for that because you're the kind of person who wants to learn about pelicans and will listen to a long podcast episode about them. You are too cool. I hope you agree that pelicans are fascinating birds. They evolved a unique build, and pouch over 30 million years ago, and they've been perfecting their feeding strategies ever since. I do find it interesting that there are so few species. For whatever reason, the family pelicanity is not one of our more diverse bird groups. Despite their limited diversity, pelicans are familiar, charming birds. They capture our hearts and imaginations. We get
Starting point is 00:35:40 a little too imaginative about them sometimes, given all the myths that persist about them. Maybe I've done a small part to dispel some of those myths today. Who knows? Before we go, I'll read you a lovely quote about pelicans from the pioneering conservationist Aldo Leopold. In a Sand County Almanac, he had this to say about some American white pelicans. Let a squadron of southbound pelicans but feel a lift of prairie breeze and they sense at once that here is a landing in the geological past.
Starting point is 00:36:16 a refuge from that most relentless of aggressors, the future. With queer antediluvian grunts, they set wing, descending in majestic spirals to the welcoming wastes of a bygone age. And so we come to the end of our episode on Pelicans. Did you learn a few new facts about these super cool birds? If so, go out there and spread your new knowledge. Thanks so much for listening. I hope you'll keep coming back for more episodes.
Starting point is 00:36:53 I have a long and ever-growing list of bird families and species that I plan to make episodes about. So stay tuned. Please consider leaving this show a review. Apple Podcasts is probably the best place to do that, but if you don't have or don't use Apple Podcasts, you can leave a review on Pod Chaser, A positive review from you would be deeply appreciated.
Starting point is 00:37:17 If you have thoughts or feelings about the show, shoot an email to Ivan at Scienceofbirds.com. You can see the show notes for this episode, which is number 14, on the Science of Birds website, scienceofbirds.com. I'm Ivan Philipson, and I look forward to learning with you next time. Cheers.

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