The Science of Birds - Ducks, Geese, and Swans

Episode Date: December 20, 2020

This episode focuses on the biological family Anatidae. This family includes the over 150 species of ducks, geese, and swans in the world. First, we highlight the key features shared by these birds, a...s well as some differences among them. We also discuss their diversity and distribution.We continue by examining the duck’s bill and the various things these birds eat.Breeding, migration, and conservation round out our look at this fascinating group of birds. Along the way, we goof around and have some fun.Links of InterestWhy a Female Duck Was Spotted with a Huge Brood of 76 DucklingsLink to this episode on the Science of Birds websiteSupport the show

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Starting point is 00:00:00 My wife and I were at the zoo one day, enjoying an exhibit on the native animals from our region. We live in Oregon in the Pacific Northwest of the U.S. Specifically, we were looking at some ducks swimming around in an enclosure behind a glass wall. We could see them up close from both above and below the waterline. It was a really cool perspective, one that you can't get when you see these aquatic birds in the wild. There were several species in the enclosure, northern pintails, buffalo heads, northern shovelers, and ring-necked ducks. We noticed that one duck was missing a leg.
Starting point is 00:00:36 We were like, aw, poor little guy. Then we spotted another duck with only one leg. And hey, there's another one. Soon, we were trying to find a duck in there that wasn't missing a leg. We came to the conclusion that all these birds must have suffered injuries in the wild and had been rescued and taken in by the zoo. It kind of warmed our hearts to see this. so now when I ask someone if they like ice cream and their response is
Starting point is 00:01:03 Do one-legged duck swim in circles? I'll know the answer. No, they don't. One-legged ducks swim pretty well, actually, at least from what I've seen. And if you don't believe me, go to the Oregon Zoo. Later that day, my wife and I were asking each other what our favorite animals were from our visit. For me, it was those lame ducks. Once upon a time, in the early days of my interest in birds, I didn't find waterfowl all that exciting. Crazy, I know. Now I absolutely love them, and I can't remember why I used to feel that
Starting point is 00:01:36 way. I have so many happy memories of seeing birds like this around the world. Andean geese in the mountains of Peru, common iders and whooperswans in the fjords of Iceland, Pacific Black Ducks in Fiji and Egyptian geese on the Nile River. You don't have to go to such exotic places to enjoy ducks, geese, and swans. Chances are, there are some fascinating species just around the corner from where you live. Hello and welcome. This is the Science of Birds. I am your host, Ivan Philipson. The Science of Birds podcast is a light-hearted, guided exploration of bird biology for lifelong learners.
Starting point is 00:02:23 In this episode, we're focusing on the bird family, anatidae, the ducks, geese, and swans. This is a big episode, so let's do a swan dive right into all the sciencey goodness. How do you know a duck when one crosses your path? Well, as Douglas Adams once wrote, If it looks like a duck and quacks like a duck, we have at least to consider the possibility that we have a small aquatic bird of the family anatidae on our hands. This was Adams' twist on the well-known duck test.
Starting point is 00:03:07 This test relies on the assumption that we are familiar with what ducks look and sound like. It's safe to say that most of us are. But people sometimes confuse other water-loving birds, like coots and grebes for ducks. These are most definitely not ducks and not members of the duck family, not even close. Grieves, coots, and loons each belong to their own families, none of which is closely related to anatidae. Today we're looking at not only ducks but all the birds in their family. What key characteristics are shared by ducks, geese, and swans? For starters, these birds are mostly aquatic, spending much of their time swimming in or at least near water. We often refer to
Starting point is 00:03:54 them as waterfowl. But waterfowl is not a scientific word. Some people lump unrelated birds into this category, birds like those grebes, coots, and loons. Used that way, the word waterfowl doesn't correspond to any real biological group of birds. The same thing is true for the word raptor, but we'll leave that one for another podcast episode. Anatids, that is, birds in the family anatidae, have bodies that are either ovoid, which means egg-shaped, or fusiform, which means tapering at both ends like a spindle. The smallest anatid is the African pygmy goose, netopus oratus. Pretty much any animal that has the word pygmy in its name is guaranteed to be cute beyond all
Starting point is 00:04:44 reason. This little bird is indeed adorable, but also beautiful. The male has a chestnut breast and flanks, black and iridescent green upper parts, and a white and green head. It's only about 12 inches or 30 centimeters long. You'll find African pygmy geese floating around in the swamps and shallow lakes of sub-Saharan Africa. The smallest species in both North America and Europe is the green-winged teal, anus creca. At 14.5 inches or 37 centimeters, this duck isn't much bigger than that pygmy goose. The colossus of the family Anatidae is the trumpeter swan, Cygnus Buxinator. This elegant North American bird is about 4.8 feet or 1.47 meters long.
Starting point is 00:05:34 That measurement includes the bird's super long neck. The trumpeter swan is also heavy, for a bird anyway, weighing in at about 30 pounds or 13.6 kilograms. Not only is this beast the largest member of its family, it's also one of the heaviest flying birds in the world. Ducks, geese, and swans have small heads relative to their bodies, and their necks are long. The number of cervical vertebrae, the spinal column bones in the neck,
Starting point is 00:06:04 varies across the avian world and among birds within the family anatidae. swans have 24 or 25 cervical vertebrae. Geese have between 17 and 23. Ducks have fewer than 16. How many neck vertebrae do you and I have? Pretty much all mammals have the same number of cervical vertebrae. Seven. So believe it or not, humans have the same number of neck bones as whales, bats, and yes, even giraffes.
Starting point is 00:06:33 The beaks, the bills, of anatids, are one of their most recognizable features. features, especially the bills of ducks. Many members of this family have the classic flattened sort of spatula-shaped bill, but there are also variations on this basic model that we'll chat about in a few minutes. Most ducks, geese, and swans use their bills to chow down on plants of one kind or another, so they're generally herbivorous, but you won't be surprised to hear that there is a fair amount of dietary variation among species. Not all of them are peace-loving quasi-hipster vegetarians like me. Some of these birds specialize in catching animal prey like fish.
Starting point is 00:07:15 Others fall within the more omnivorous part of the spectrum, adding some small invertebrates to their plant-based diets. The wings of anantids are relatively short and pointed. They allow for fast, strong flight. Nucks and their relatives need to flap almost constantly while in flight, since their short wings don't allow for much gliding. Some duck species that feed at the surface or in very shallow water can take off explosively from the water.
Starting point is 00:07:44 Their powerful pectoral muscles, which drive the wings, make this possible. Other species need to get a sort of running start across the water's surface before they can get airborne. Now, I'm sure you know the expression, like water off a duck's back. These birds really do have remarkably watertight plumage. As aquatic birds, ducks and other anatids need to prevent water from soaking their insulating down feathers, because down loses its ability to keep a bird warm if it gets wet. The outer contour feathers overlap to form a sort of shell to keep water out,
Starting point is 00:08:20 like a Gortex rain jacket. Contour feathers have a fine scale structure that causes water to form beads and just roll off. This waterproofing is enhanced and maintained by oils from the bird's Euripigial or preen gland. The plumages of birds in this group are most often some combination of brown, gray, black, and white. But there are many species that are much more colorful. This is particularly true for male ducks. A few of the most attention-demanding examples are the harlequin duck, the wood duck, and the mandarin duck. The latter two birds are close relatives, both belonging to the genus Ikes. The male Mandarin duck is just, just totally over the top. Its plumage is a gorgeous patchwork of orange, blue, purple, black,
Starting point is 00:09:10 white, cream, and green feathers. I'll put a photo of this species in the show notes on the Science of Birds website. Birds, in general, replace their feathers once or twice a year. This is the process of molting. The ability to fly is so crucial to birds that most of them molt or shed only a few wing or tail feathers at a time. That way they maintain their ability to fly. But Anatids shed their primary wing feathers all at once in the fall. That means these birds are grounded, unable to take to the sky. This lasts for about a month, during which the birds are vulnerable to predators. So ducks, geese, and swans tend to lie low at that time of year. They keep out of sight until their new wing feathers grow in. This trait isn't used to,
Starting point is 00:09:58 unique to birds in the family anantity. Some other water-dwelling birds like loons and grebes also molt their flight feathers all at once. What sounds do these birds make? Well, they definitely aren't songbirds, taxonomically or figuratively. They don't sing, and few would describe their calls as melodious. Here are some examples, starting with... If you live in the U.S., you definitely know who those dudes are. That's right, Canada geese. Branta Canadensis. This species has been introduced to Europe, so this sound has become familiar there as well.
Starting point is 00:10:51 How about this one? You won't hear that species in the U.S., not in the wild anyway, but it's abundant in Western Europe. It's the gray lag goose, answer answer. This species is the ancestor of our domestic goose. Okay, this next one. There's a good chance you know who this is. Yep, that's our friend the mallard, anis platyrincos. This bird is super common in North America and Europe, and it's found over most of the Northern Hemisphere.
Starting point is 00:11:40 Sounds are fun, so let's do a couple more. Here are some white-faced whistling ducks in Brazil. The eight species of whistling ducks all belong to the genus Dendro-Syx. This is, in some ways, the most genetically distinct group of birds within the family Anatody. Whistling ducks are so weird that they were once separated into their own family. Here's another bird call. This is the Cape Barren Goose from Australia. Compared to songbirds, most ducks, geese, and swans don't vocalize all that much. The sounds they do make are relatively harsh, like the grunts, honks, quacks, and whistles in our examples.
Starting point is 00:12:32 Now, I don't know about you, but I still love hearing these sounds. The famous American explorers Lewis and Clark had something to say about the sounds of waterfowl. In his journal entry from November 5, 1805, Captain William Clark wrote, Rain continues this morning. I slept but very little last night for the noise kept during the whole of the night by the swans, geese, white and gray brant ducks on a small sand island close by. They were immensely numerous, and their noise horrid. That happened 215 years ago, not far from where I live. Thankfully, those birds are still out there, making their cacophony of horrid noises.
Starting point is 00:13:24 With about 165 species of ducks, geese, and swans, the family anatidae is pretty diverse. Let's talk a little about this group's diversity, distribution, and evolution. As a group, these birds are cosmopolitan. We talked about that word in episode 16, which was about the peregrine falcon. A cosmopolitan species or family lives pretty much all over the world. Anatids are indeed widespread. You'll find them everywhere except in the heart of the Sahara Desert and the interior of Greenland.
Starting point is 00:14:04 And, of course, there's one other place you won't see a duck, goose, or swan. That's right. Say it with me, kids. Antarctica! Okay, okay, I should point out that very rarely black-necked swans show up at the northernmost tip of the Antarctic Peninsula. This species normally breeds in Southern South America. But looking at data in e-bird, this species was reported in Antarctica only once in 1995. There were two of them and they both died. Sad, I know. But dig this. I want to tell you about another bird that died in Antarctica a few years earlier. Actually about 67 million years earlier. In 1993, a fossil bird was
Starting point is 00:14:52 found on the Antarctic Peninsula, on Vega Island. Paleontologists eventually gave it the genus Vaguevis. Vigavis appears to have been a diving bird, and its closest living relatives are our ducks and other annatted buddies. And in case you're wondering, Antarctica back in the day wasn't all frozen and barren. Sixty-seven million years ago, it was still part of the supercontinent Gondwana. It was covered in forests and crawling with dinosaurs. The discovery of Vagavis was enormously important in the field of ornithology. It provided the first fossil evidence that some modern bird lineages started to diversify
Starting point is 00:15:35 millions of years before the big extinction that killed off the other dinosaurs. Most of the bird orders and families we know today trace their origins to the crazy times after the asteroid hit Earth 66 million years ago. But now we know for sure that some relatives of ducks were waddling around in the Cretaceous period, in the shadows of Tyrannosaurus and Triceratops. Pretty cool, huh? One big take-home message here is that the ducks and other birds we're talking about today represent an ancient bird lineage. Birds like these have been around a long, long time. From their southern origins in Gondwana,
Starting point is 00:16:19 a natids spread northward in the last 25 to 30 million years, making their way across the planet. Today, these birds occupy a wide variety of freshwater and marine habitats. You'll find them grazing on the tundra, in alpine meadows, and on golf courses. You'll see them paddling around in swamps, estuaries, lakes, ponds, billabongs, bays, rivers, and your local sewage treatment plant. Boy, do they love sewage treatment plants. Several major divisions have formed within the family Anatidae over its long evolutionary history. A few of these distinct genetic lineages are treated as sub-families.
Starting point is 00:17:02 Most species belong to one of two sub-families, anatine or ancerinni. Notice the suffix for sub-family here is knee. Knee, knee, knee, knee, knee, knee, me, who are you? We are the knights who say, No, not the night you say knee. The same. If you don't know what that soundbite was from,
Starting point is 00:17:25 stop this podcast episode right now and go watch Monty Python and the Holy Grail. I'll be here when you come back. Right, sub-families. Anatony and Ancerany. Now, I know we're getting into the weeds a little bit with this taxonomy stuff, but don't get nervous and start looking around for the exit.
Starting point is 00:17:44 Stick with me because it's not so bad and, hey, this is science, yo. The subfamily anatonee includes most of the birds that you and I call ducks. The other major subfamily, Ancerany, includes most of what we call geese as well as all of the swans. In addition, there are some ducks that don't fit into the Anatine or Ancerany subfamilies, like those whistling ducks I mentioned earlier. Or the six birds in the genus Oxyura, including our familiar ruddy duck. Those birds, too, stand apart in their own group.
Starting point is 00:18:21 And, if anything, these oxyura ducks are more closely related to swans and geese than other ducks. Weird, huh? The point here is that the birds we call ducks, geese, and swans do not fit neatly into their own respective sub-families. As is often the case, the common names we use do not reflect the reality of nature. They don't necessarily conform to the real genetic evolutionary relationships among birds. The problem with common names might deserve its own podcast episode, so I won't get all riled up about it now. But I will give you an example of what I'm talking about.
Starting point is 00:19:00 The blue-winged goose is a chunky, grass-munching bird that lives in high-elevation meadows in Ethiopia. To me, its facial expression looks innocent and sweet, like a gosling that never grew up. You would probably agree with me that this bird looks like a goose. Fair enough. But its closest relative is actually Heartlaub's duck of Western Africa. All the blue-wing goose's close relatives are called ducks. Genetically, and therefore taxonomically, this bird sits squarely within the subfamily Anatony. Recall that this is the group that includes most of the world's so-called ducks.
Starting point is 00:19:41 So what the heck is a duck? and what is a goose? Like, really? Honestly, I can't give you a simple answer. There doesn't appear to be one sharp dividing line between these birds at the genetic level. Over millions of years, duck-like birds and goose-like birds have evolved more than once, independently within the family Anatity.
Starting point is 00:20:03 If I was renaming birds in this family, I would, I don't know, maybe try to simplify things and just call them all ducks. Sorry, kids, because that would effectively ruin the game Duck, Duck Goose. It would just be Duck, Duck, Duck, Round, Round, Add Infinitum. Not a very fun game. In practice, the birds we call ducks tend to have the classic flat duck bill. They have shorter necks, and they usually show distinct plumage differences between the sexes.
Starting point is 00:20:36 The birds we call geese have deeper bills more suitable for grazing than dabbling. geese show few if any differences between males and females, and they often form long-term bonds with their mates. Okay, let's crawl out of the taxonomy rabbit hole and get back to some more nuts and bolts. Now, what about scoters, teals, scops, hardheads, golden eyes, iders, smews, poachers, Morgansers, wiggins, pintails, garganese, shovelers, and so on.
Starting point is 00:21:08 These are just different types of ducks. Each of them has distinguishing physical features and behaviors, and each of them has its own charms. The common names here, teal, scop, etc., mostly correspond to one or more genera. So, for example, the six scotor species are all ducks in the genus Melanita. Then we have dabbling ducks and diving ducks. I'm sure these terms are familiar.
Starting point is 00:21:38 familiar to you. They describe feeding behaviors. So they're helpful for identifying ducks in the field. If you see a duck disappear underwater for a few moments, then pop back up like a cork, that narrows down the list of possible species. You know it's probably one of the diving ducks. But the terms dabbling duck and diving duck do not correspond very well with any real genetic lineages in ducks. Some might argue with me on this point because reasons, but I'll just leave it at that for now. Dabbling ducks like the mallard and northern pintail tend to forage in shallow water. As they munch aquatic plants below the surface, their feathered duck butts tip up to the sky. It's a wonderful sight to behold. These dabblers rarely completely submerge
Starting point is 00:22:29 themselves. Diving ducks, on the other hand, swim around underwater as they hunt for plants or animal prey. They spend more time in deeper water. Examples from this group include scops, golden eyes, the common poachered, and the buffalo head. Next, let's look closer at the beaks of these birds and talk more about how they eat. But first, I'm going to take a quick break to drink some coffee, and I have a favor to ask of you. If you're enjoying the Science of Birds podcast, if you find it educational, entertaining, whatever, it would be fantastic to get a review from you.
Starting point is 00:23:09 If you're listening to me on Apple Podcasts, you can leave a review there. If you're listening on Spotify or another app, a great place to leave me a review is at podchaser.com. Podchaser is a free resource for people who love podcasts. Just search for the Science of Birds on that website, and you can leave a review. If you're new to Podchaser,
Starting point is 00:23:30 you'll need to create an account first, but it's easy and free. Reviews really help me spread the word about the podcast, so thank you, seriously. Now, let's get back to those birds. The business end of a duck or goose is the bill. Picture the classic duck's bill
Starting point is 00:23:51 with its flattened shape. If you're imagining a mallard, I'm right there with you. It's a splendid example. Maybe you recall that the scientific name of this species is anus platyrincos. Platirincos translates as flat bill or flat snout. What is the advantage of this bill shape? How does it work? The basic mechanism works like this. A duck sticks its head into water or some stinky mud to feed on small plants, seeds, or invertebrates. It opens and closes its bill rapidly.
Starting point is 00:24:27 but not very widely. Water or mud and any food items enter the bill near the tip. This material gets sucked into the mouth and then exits out the sides closer to the bill's base. Lining the inside edges of the upper and lower bill
Starting point is 00:24:43 are dozens of small blade-like structures called lamelli. These lamelli are packed close together. As water leaves the bill, food items get trapped in the lamelly. This is similar to how Baleen works in the mouths of whales. So a duck's bill is a filter-feeding apparatus.
Starting point is 00:25:04 These birds strain their food from water or mud. As a generalist omnivore, the mallard eats many things, not just tiny filterable tidbits. It will also eat large insect larvae, worms, snails, crayfish, leaves, roots, rice, wheat, corn, and so on. And a mallard will happily scarf down just about anything a human will toss at it. Bread, watermelon, sushi, pizza, tater tots, whatever. Clearly then, the distinct shape of a duck's bill works for more than just filter feeding. And apparently, this bill shape gives ducks a lisp when they speak English. Oh, crazy ducks, knocking themselves out flying south for the winter.
Starting point is 00:25:49 Why, they just don't use their brains. Another interesting feature of duck bills and those of geese and swans is they have a soft rubbery outer layer. This outer sheath of keratin, called the Ramphothica, is hard and horny in most other birds. Anatids all have a small, hard projection at the tip of their upper bill. We call this the nail. The nail functions sort of like a claw or fingernail, allowing the bird to more easily grab stuff, stuff like the aforementioned tater tots. Underneath the nail, there are rows of tiny nerve receptors called touch papilli. Collectively, these papilli form the bill-tip organ.
Starting point is 00:26:34 This sensitive organ allows ducks and other anatids to feel around in the mud or in murky water to find goodies with their sense of touch alone. Among duck species, there are many variations on the standard-issue duck bill, some more dramatic than others. It all depends on what a species eats. I'll highlight a few examples. First, we have the five species of Murgansers. These ducks have long, thin bills with serrated edges.
Starting point is 00:27:04 This is a major departure from the normal duck bill shape. Murganzers eat mostly small fish. Those serrations on their bills help them hold on to their slippery, thrashing prey. Plus, Murganzers have cool mohawks. Then there are the scoters. These are ducks that spend a lot of time in coastal marine waters. They specialize in another type of animal prey, mollusks and other marine invertebrates. These ducks dive beneath the waves to scoop up clams and rip muscles off of rocks.
Starting point is 00:27:38 Their bills are thick and strong, but they don't crush the shells of their prey with their bills. They just swallow them whole. The four species of steamer ducks are South America's answer to the scoters. steamer ducks are chunky coastal birds that scoop up marine invertebrates with their thick bills. Interestingly, three of the four species are flightless. The last example I'll give you of a not-so-average duck is the pink-eared duck of Australia. This bird is an oddball, both in the way it looks and in the sense that ornithologists haven't quite figured out how it's related to other members of the Anatty family.
Starting point is 00:28:19 The pink-eared duck has a long flat bill. Near the tip of the upper jaw, a rubbery flap of skin dangles conspicuously from each side. These birds are primarily filter feeders that eat microscopic algae and other tiny things in the water. Ornithologists don't know for sure what those flaps do, but most likely they help the ducks find food with sensitive touch receptors. I'll include a photo of this weird, wonderful bird. in the show notes for this episode on the website. I should also mention another filter-feeding duck, the northern shoveler. This bird is widespread across the northern hemisphere.
Starting point is 00:29:00 It has a massive schnaz, a really long, wide bill. The shoveler uses its bill to strain tiny crustaceans from the water as it motors along on the surface. Okay, before we move on to talking about breeding in anatids, I want to make sure I don't completely neglect our friends the geese and swans. They have bills too, you know. Geese and swans are primarily herbivores. Their bills tend to be deeper than those of ducks, more arched, less compressed from top to bottom. Swans forage in several ways, including dabbling at the surface and plucking aquatic plants underwater while upended. They take
Starting point is 00:29:43 advantage of their long necks to reach down into the depths. The several independent lineages of birds we call geese are almost all grazers. They tend to forage while walking around on land. The gray lag goose, for example, eats grass, roots, leaves, grain, and many other plant foods. Once a year, ducks, geese, and swans seem to think it's necessary to make more ducks, geese, and swans. To accomplish this task, they form monogamous breeding pairs. But there's some variation in the degree of monogamy in this family. Swans are the most loyal, usually mating for life.
Starting point is 00:30:34 Many geese do this too. In these birds, both males and females help raise the young. In some other species, monogamous pairs stick together for only a few years, and many ducks are monogamous through a single breeding season only, seeking a new partner each year. Sexual dimorphism is common among ducks, but mostly non-existent in the geese and swans. Sexual dimorphism is where males and females have different forms, or morphs. In the breeding season, many male ducks have brighter, more showy plumages. than their female counterparts,
Starting point is 00:31:11 like the Mandarin duck I mentioned earlier. Males can have various ornaments, like long tail feathers, bright patches of skin, and even weird growths on their bills. For example, males of the knob-billed duck and its close relative the comb duck have an enormous fleshy, crest thingy,
Starting point is 00:31:32 growing from the top of their bill. The bright colors and wacky ornaments of male ducks result from millions of years of females choosing to mate with males that have such traits. This is classic sexual selection. We'll definitely do a whole podcast episode on sexual selection at some point. It's fascinating stuff. So our fancy-looking male ducks try to win the attention of females, but they don't just float around on the water passively looking pretty.
Starting point is 00:32:02 It's not like a male just yells, Attention females of the pond. Behold my glorious plumage. Who among you wishes to be my mate? Luckily for you, I am now accepting applications. Please form a line and have your resumes ready. Courtship is usually a more active affair. Males use courtship display behaviors to win the hearts of females. Wood ducks, for example, display numerous courtship behaviors. Some are unique to the colorful male. Others are used by only the female, and some are used by both sexes. Here are the descriptive names for some of these behaviors in wood ducks. Turn the back of the head, chin lift, display shake, rush, bill jerk, and burp. In the wood duck and other species, different behaviors are used depending on the stage
Starting point is 00:32:56 of courtship. Some behaviors initiate the pair bond, others are used later to strengthen and maintain it. Now, I'm about to talk about bird sex, briefly. This is the science of birds after all, and we don't want to shy away from this topic. It's so important biologically. If you'd prefer to pretend that animals don't have genitals, or if you've got a kid sitting next to you and you haven't had the birds and the bees talk yet, well, maybe put some earmuffs on or skip ahead a couple minutes. You've been warned. There are some really interesting things about the sex lives of birds in the Anatity family. I'll highlight only one now, since we don't have time to get into all of it. Among all the world's birds, most males don't have anything that resembles a penis. They just
Starting point is 00:33:48 have a cloaca that seems pretty similar to that of the female. The cloaca is the single opening at the back end of a bird where waste comes out and where copulation takes. And where copulation takes. place. But about 3% of bird species do have a penis. It's not at all the same thing as the organ found in mammals. It evolved independently as an extension of the cloaca. Technically, it's called a cloacal phallus. Most of the world's bird species that have this organ are ducks and geese. Depending on the species, the male's cloacal phallus might be short or it might be long, Like, really long. In fact, the lake duck, oxyura vittata, has the longest phallus relative to body size of any bird.
Starting point is 00:34:36 This close relative of the ruddy duck lives in South America. The bird's body is about 23 inches or 59 centimeters long. Its cloacal phallus is more than half as long as its body. The longest on record that I know of is 16.7 inches, which is 42.5 centimeters. crazy. If most birds don't have or need a phallus, why do so many ducks and geese have this structure? And why are some so dang long? One hypothesis offered for a long time was that the phallus is an adaptation for mating in the water, which is what many of these birds do. That seems like a reasonable explanation. More recently, however, ornithologists have come up with some
Starting point is 00:35:21 hypotheses that are far more complicated and, I think, more interesting. But we'll leave that topic for another day, since we've got other fun stuff to talk about and we need to keep moving here. Okay, so our birds have mated, eggs have been laid, and it's time to raise a family. For species like swans and many geese, both parents will take part in caring for the youngsters. This isn't the case for many ducks. The rule of thumb seems to be. seems to be that in species with strong sexual dimorphism, dad doesn't stick around. Those flashy, colorful males might help the female build the nest
Starting point is 00:36:00 or protect her in the eggs for a little while, but these males usually drift off once incubation is well underway. This makes some sense, since a male is super conspicuous, he might attract predators to the nest if he stayed close to his family. Females, on the other hand, have cryptic plumages, they're camouflaged as they sit in their nests. This might explain why even male harlequin ducks don't stick around to raise their ducklings. You see, harlequin ducks are abnormal because they form long-term pair bonds,
Starting point is 00:36:35 unlike most duck species where the male has such showy plumage. The same monogamous pair of harlequin ducks meets up year after year to mate. Males in long-term pairs in other species like geese usually stick around to raise their babies. Maybe the highly conspicuous male harlequin duck would endanger his family if he stuck around. Predators would see him a mile away. So he leaves his family behind, then reunites with his lady the next season. Baby ducks, geese, and swans are not only obscenely adorable, but also capable of feeding themselves not long after busting out of their eggs. And they can swim right away too. So these young birds are precocial. They're born covered in fuzzy down with their
Starting point is 00:37:23 eyes open. They're ready to follow mom all over the place and maybe get themselves into some trouble. Sometimes the young of several families will gather together in one group. One or a few adult birds will take care of the entire gang of babies, sort of like daycare. Ornithologists call this a creche, C-R-E-C-H-E. The phenomenon of creching behavior is seen across the avian world, from flamingos and penguins to boobies and turns. A couple years ago, a female common Murganzer made the headlines here in the U.S. when she was spotted with a crash of 76 ducklings in her care. 76! She was swimming around on a lake with a long line of fuzzy merglitz in tow. Merglitz isn't a real word, but maybe we can make it a thing.
Starting point is 00:38:16 Every word has to start somewhere, right? Oh, wait, I just looked it up. I'm not the first person to say merglet. Dang. Oh, well, back to Mama Murganser. Creshes are not necessarily rare in this species, but no one had ever seen a single female taking care of so many young. Who knows what happened to the other Murganser mothers?
Starting point is 00:38:39 And good thing the ducklings could feed them. themselves, otherwise there's no way this would work. After a month or two, young ducks, geese, and swans will fledge. In many duck species, parents abandon their young not long after fledging. The parents of some larger species like geese and swans will stay with their offspring through the young bird's first migration and winter. If they're lucky, many species of wild ducks, geese, and swans can live for over 30 years. The V formation of migrating geese, ducks, and swans is an icon of nature across the world. This behavior helps the birds conserve energy on their long-haul flights.
Starting point is 00:39:28 Each bird in the V formation flies slightly higher than the one in front of it. The movement of air over the wing of the bird in front reduces drag on the bird behind. The bird at the very front doesn't get this benefit. of course. So when the lead bird gets tired, it falls back and another takes its position. Migration is common in this family of birds. Many migratory species breed in temperate or polar latitudes, either north or south. The days are long in these regions and food is plentiful. But when winter comes, their watery habitats freeze over and or food becomes scarce. So they gather in flocks and fly to warmer places.
Starting point is 00:40:12 They find ice-free wetlands, lakes, or bays to spend the winter. It's during this time that males of many species take on their colorful breeding plumage and courtship begins. Remember that these birds molt their primary wing feathers all at once, after the breeding season ends in the fall. They become flightless. Many male ducks at this time wear a short-term drab camouflage. plumage. It's called eclipse plumage. This helps the flightless males hide from predators when
Starting point is 00:40:45 they're so vulnerable. Flightless birds obviously can't migrate. What many species do right after the breeding season is fly to a haven, a sort of protected staging ground. Then they mold their flight feathers. After a month or so, they have shiny new primary feathers and they complete their migrations, flying onward to their wintering range. Birds that do this are called molt migrants. The surf scoter, for example, is one duck that does this. After breeding, these birds migrate to distinct molting sites, mostly in coastal waters. I did an entire episode on Migration, Episode 4, so you can check that out to learn more. Now, let's talk about the status of our ducks, geese, and swans from a conservation perspective.
Starting point is 00:41:39 For thousands of years, humans have been hunting these plump, greasy birds for food and feathers. Since the year 1500, we've been responsible for the extinctions of seven species in this family. In every case, hunting was to blame. The most recent extinction was of the Labrador Duck, a sea duck that lived off the east coast of North America. It was last seen in New York in 1878. This was the first bird species to go extinct in the new world after Columbus landed here. Across the world today, there are six critically endangered species in this family, as well as seven that are endangered and 18 that are vulnerable.
Starting point is 00:42:27 Those are categories from the IUCN's red list of threatened species. So this means that about 18% of the birds in this family are globally threatened. Hunting is a threat to almost all of these red-list species, but overall ducks, geese, and swans face many other pressures too, including habitat destruction, pollution, and invasive species. Many efforts are being made by government agencies and conservation organizations around the world to protect threatened waterfowl. One interesting success story comes from the work of Ducks Unlimited here in North America.
Starting point is 00:43:07 This nonprofit organization has been around since the late 1930s. Its mission is to conserve habitat for waterfowl and whatever wildlife shares that habitat. Ducks Unlimited has conserved almost 15 million acres of wetland and grassland habitats in Canada, the U.S. and Mexico. That's about 60,700 square kilometers. Pretty impressive. But here's the catch. The almost 1 million members of Ducks Unlimited,
Starting point is 00:43:37 are overwhelmingly waterfowl hunters. The underlying motivation for the organization to preserve habitat is to make sure hunters have a steady supply of birds to blast out of the sky with shotguns. In case it's not obvious, I'm not a big fan of hunting for sport. But my personal feelings aside, I think this represents a challenging ethical dilemma in the world of conservation.
Starting point is 00:44:03 It's similar to how trophy hunting for rhinos and other African megafauna can supposedly raise funds for the conservation of those animals. Ducks Unlimited has, without question, helped many populations of annatted birds, and as a byproduct of protecting bird habitats, this organization has helped hundreds of other wildlife species.
Starting point is 00:44:26 I've certainly spent plenty of time enjoying the birds and natural wonders of places protected with the help of Ducks Unlimited. Under this model of conservation, many bird populations benefit from habitat protection, but the price of that protection is the killing of countless individual birds. The birds shot by hunters are sort of
Starting point is 00:44:48 taking one for the team, not that the birds have a say in the matter. So, is all of this okay? I leave you to decide for yourself. For what it's worth, I'm conflicted about it. As much as I hate to see any animal killed, I see both pros and cons to this approach. It's definitely better than the usual human method of operation,
Starting point is 00:45:11 destroying wetlands and killing birds with no restraint, for fun and profit like there's no tomorrow. But it would be nice if we would pour this amount of money and effort into protecting wild animals and natural ecosystems simply because we value them for their own sake, for their intrinsic worth, rather than treating them as something for people to use as a resource. So maybe we should start an organization called Birds Unlimited,
Starting point is 00:45:39 or maybe Birds Unchained, or Birds Totally Out of Control. Birds Gone Wild? I don't know. In any case, we could protect birds and their habitats just because. I know I've gone off on a tangent, but I think this is important stuff to think about, and the inspiration for this tangent was Ducks, so there you go. One way or another, we need to protect our planet's 165 wonderful duck, goose, and swan species. The world is a much better place and a much noisier place with them in it. So ends our epic episode on the family Anatity.
Starting point is 00:46:23 I hope you learned a few things and understand these lovely birds a little better. I really appreciate you for your. interest in birds and for taking time to learn with me today. If this is your first time listening to the Science of Birds podcast, I hope you'll subscribe and check out more episodes. If you have thoughts or feelings about the show, shoot an email to Ivan at Science of Birds.com. You can check out the show notes for this here episode, which is number 18, on the Science of Birds website, scienceofbirds.com. This is Ivan Philipson, and I look forward to nerding out about birds with you next time. Cheers.

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