The Science of Birds - Waxwings

Episode Date: December 4, 2022

This is Episode 65, and it’s all about waxwings—birds in the family Bombycillidae. The Cedar Waxwing is one species, and there are two others that we’ll talk about.These beautiful, elegant songbirds are loved by people across the Northern Hemisphere.Waxwings are easy on the eyes, for sure, and that’s great. I mean, personally, I think they’re just about the most gorgeous songbirds we have in North America. But their biology is also really interesting. So much of how waxwings live and behave is dictated by what they eat… By their specialized diet. What is that special diet? Is it maybe something like scorpions, psychedelic mushrooms, or the blood of their enemies?  Listen and find out!Links of InterestCedar-Waxwings getting drunk on Holly Berries [VIDEO]Cedar Waxwing Courtship [VIDEO] ~~ Leave me a review using Podchaser ~~Link to this episode on the Science of Birds website Support the show

I've loved animals and the natural world for as long as I can remember, since I was a little kid, and maybe this is true for you too. But I haven't always been as obsessed with birds as I am now. Don't get me wrong, I never disliked birds. I definitely appreciated them, but I just didn't spend much time looking at them, or really truly listening to them. One breakthrough happened for me when I was working on my master's degree in biology. This was a couple decades ago in Southern California.

One day I was walking across campus with Tony, my advisor. I was his graduate student, and I spent countless hours in his lab. We're walking along, and suddenly Tony stops. He points up to the sky and says, do you hear that? No, what are you talking about, I say. Those are Cedar Wax Wings calling, he says, with a wide grin. I listen again, and then, yes, I hear a sound. soft, high-pitched sound.

Oh, you mean that? I ask. We never even saw the birds. But I was in awe of Tony's ability to, A, detect that faint bird call from among all the other sounds on a busy college campus, and B, instantly know which species was making it. My little mind was blown. You see, Tony was and is a serious bird. Burder. Back then, he was the president of the local chapter of the Audubon Society. But I wasn't a birder yet in those days. I kind of wish I had been because I'm sure I could have learned a lot more

about birds from Tony. I like to think I've come a long way since then. Now I know most of the songs and calls of my local bird species. And I get a little tickle of satisfaction and happiness every time I hear Cedar Wax Wings fly overhead. Now I'm the one who points out wax wings calls to other people. It seems that the student has become the master. And in fact, I even have a master's degree to prove it. Just kidding. I mean, I did get the master's degree, but I feel like I'll always be a student when it comes to birds and to the natural world in general. There will always be more to learn. But I'm so grateful to Tony and to those Cedar Wax Wings for inviting me to be more aware of birds

and to get to know them by their sounds. Hello and welcome. This is the Science of Birds. I am your host, Ivan Philipson. The Science of Birds podcast is a light-hearted exploration of bird biology for lifelps. long learners. This is episode 65, and it's all about wax wings, birds in the family bombicility. The cedar waxwing is one species, and there are two others that we'll talk about.

These beautiful, elegant songbirds are loved by people across the northern hemisphere. Wax wings are easy on the eyes, for sure, and that's great. I mean, personally, I think they're just about the most gorgeous songbirds we have in North America. But their biology is also really interesting. So much of how wax wings live and behave is dictated by what they eat, by their specialized diet. What is that special diet? Is it maybe something like scorpions, psychedelic mushrooms, or, or ooh, ooh, the blood of their enemies? No, nothing quite so exciting as all that. Wax wings specialize in eating fruit, mostly sweet berries. So join me, my friend, as we step into the world of the wax wings

to learn about how they eat, how they breed, how they sound, and more. There are just three wax wing species in the world. the Cedar Wax Wing, Bombacilla Sidrorum, the Bohemian Wax Wing, Bombacilla Gerylis, and the Japanese wax wing, Bombacilla Japonica. Superficially, these species all look very similar, and as far as we know, they share most features of their biology. All wax wings are medium-sized songbirds.

The smallest is the Cedar Wax Wing, at 6.1 inches long, beak to tail. That's 15.5 centimeters. The largest is the Bohemian wax wing at 8.1 inches, or 20.5 centimeters. The Japanese wax wing is intermediate between those two. The body and wing shape of a wax wing are pretty typical for a songbird that lives at the edges of forests. But it has a prominent crest on its head, sort of like a blue jay or northern cardinal or crested tit. The bill is small and dark-colored, and the tail, has a squared off tip. To me, a wax wing has an overall satin smooth and streamlined look,

like all of its rough edges were sanded down or something. The plumage of wax wings is brownish pink overall. You can't really see the outlines of the contour feathers. They all just blend together into a uniform, creaminess, for lack of a better word. Now, this might seem silly, but the car I drive is a pickup truck. Well, I mean, that's not the silly part. Some would say it's actually cool to drive a truck. But I named my truck. Named it Wax Wing. Seriously, because it's a tan sort of light brown color that reminds me of the bird. And the roof rack on top is vaguely reminiscent of a Wax Wings head crest. But it's normal to name your car, right? Tell me I'm not alone here. I'm sure that, like me, you name all sorts of things around your house. My toothbrush, for example, is Mr. Bristles,

and my toaster's name is Travis. But never mind. Wax wings, the birds, are way more colorful than just being all silky brown like some cool guy's truck. Cedar and Japanese wax wings have some yellow on their bellies. And all three species have bold black and white markings around the eyes and on the chin and throat. The black around the eyes looks sort of like a little superhero mask. The wings, too, have some bold, black, white, gray, and, in the case of the bohemian wax wing, yellow markings. The tips of the gray tail feathers are bright yellow in cedar and bohemian wax wings, whereas the Japanese species has a red tail tip. All of these birds look like they dipped their tails ever so slightly into a can of bright colored

paint. But, okay, what about the wax, man? Why are these birds called wax wings? Well, adult cedar and bohemian wax wings have some wing feathers that appear to have droplets of red wax at their tips. These are feathers of the inner wing, what we call secondary feathers, or just secondaries. The number of secondaries that have these waxy nubs is variable from one individual to the next. It depends on the age of the bird. Roughly speaking, birds with less than six waxy nublets per wing are immature. More than eight or nine, and you've got yourself a mature individual. The older the wax wing, the more waxy-tipped feathers it has. The droplet-like feather appendages we're talking about aren't really made

of wax, though. These structures are actually part of the feather shaft. The rakis, which means the waxy nubs are made of the protein carotin, not wax. Something waxy isn't necessarily made of wax, right? Just like candy labeled Chocolat-y is like chocolate, but not actual chocolate. It's chocolate-ish, chocolate-adjacent. Chocolaty is used as a devious marketing ploy to make you think the hollow Easter bunny you found in the bargain bin at the dollar store is made of real chocolate. chocolate. Sorry, it's not. I'm pretty sure the main ingredient is actually sawdust. Yuck! So maybe, to be scientifically more accurate, we should have named these birds

waxy wings instead. In any case, each of the red nubs is the wide, flat tip of the feather shaft. It includes a number of tiny branches, or technically barbs, that have fused together into a glossy little keratin droplet, like a tiny lozins-shaped amulet. And hey, if you need a refresher on words like Rakesh and Barb, you can check out episode 13 of this podcast, which is titled Feathers, Form and Function. The red color of the waxy feather tips comes from a carotenoid pigment called Asta-Zanthan. Astazanthin.

Remember that many of the red, orange, and yellow colors we see in birds come from carotenoid pigments. And the ultimate source of those pigments is the diet of the birds, often from plant products like seeds and berries. The waxy nubs and colorful tail tips of wax wings are ornaments that most likely have important meanings to the birds. It seems that they're social signals. They reflect a bird's age and social status. Older wax wings have more waxy nubs, right? Researchers have found that mature wax wings pair up with other mature wax wings. Likewise, younger birds with fewer nubs pair up with other young birds. Those more mature pairs tend to be more successful in raising offspring. They nest earlier and fledge more chicks. So it's

possible that wax wings are using those feather ornaments as a way to choose their mates. Interestingly, the secondary feathers of Japanese wax wings rarely have waxy tips, but they do have small red spots of color in those feathers in pretty much the same location. As I mentioned, cedar and bohemian wax wings have yellow tail tips. But occasionally, at least with cedar wax wings, a bird shows up with a tail tip that's orange, not yellow, orange. is it orange or orange how do you say it orange let's go with orange i don't know but this uh this phenomenon this only started happening about four or five decades ago this orange tail tip thing what's up with that well we know the color of the tail tip comes from carotenoid pigments and those pigments are

derived from the things wax wings eat berries and such it turns out there's a plant that humans introduced to North America from Asia, which has become an invasive species. It's called Moro's honeysuckle, or Japanese honeysuckle. Wax wings love to gobble up those honeysuckle berries. And when they do, they eventually end up with orange tail tips. That's because Moro's honeysuckle berries contain a red carotenoid pigment called rhodozozanthin. Wax wings can't really process rhodo xanthin to turn it into a yellow pig. So red rhodozoanthin mixes with some of the normal yellow pigments, and you get orange.

As always, I'll put some photos of the birds I'm talking about in the show notes for this episode on the Science of Birds website. Check them out, especially if you don't know what a wax wing looks like. They're gorgeous birds. That was a lot about what wax wings look like. Now let's talk a little about their behavior and their voices. These are social birds that often gather in large flocks, especially in winter. But they also build their nests in small, loose groups in the summer. The scientific name of the bohemian wax wing is bombacilla garrulis.

That second word is a nod to the social nature of these birds. Gerales comes from the Latin and refers to the chattering and babes. sounds that bohemian wax wings make when together in a flock. They're talkative little buggers. Even in English, garrulous means excessively talkative, especially about trivial things. You can probably think of a few garrulous people you've come across in your life. This fact that wax wings gather in large winter flocks is a great example of a behavior that reflects their specialized diet. The small fruits and berries they eat are low. locally abundant. Some biologists use the term super abundant. But this resource is, at the same

time, haphazardly scattered across the countryside. Trees and shrubs with ripe fruit on their branches are found only here and there, at least in the winter. Traveling in a flock makes finding food more likely than going it alone. And when a flock of wax wings finds a tree or bush full of berries, the birds are surprisingly courteous with each other. They don't squabble over berries or beat each other up in competitive fights for dominance. They're generally docile, calm, and cooperative. Wax wings all just stuff their little gullets full of sweet berries and life is good. There's no need to fight for a limited resource when the resource isn't very limited, when it's super abundant. A second aspect

of waxwing biology related to their fruit-tastic diet is their vocal sounds. Even though wax wings are technically songbirds, in the genetic evolutionary sense, they don't sing. That is, wax wings don't use ritualized vocal displays to establish and defend a territory. Not having a song is a highly unusual characteristic for a song bird. These peace-loving little hippies just aren't territorial. There's so much fruit to go around, who needs to get all uptight and try to keep a tree or berry patch all to themselves? But wax wings still have a thing or two to say to each other. They may not sing, but they do have plenty of calls. These vocal sounds are used to communicate in different social contexts. For example, subtly different calls are used during

flocking, nest building, and courtship. To human ears, most waxwing calls sound pretty dang similar. But we can usually notice enough differences among them to sort them into two categories. First, there's the B-Z-E category. That's B-Z-E-E-E-E. B-Z-E-E calls are more buz-y and have a little bit of a rattle to them. Here's an example. Now all of the calls I'm going to play for you are pretty high-pitched, so I'm sorry if they're hard to hear, or if they're a bit shrill. Okay, here's an example of a bzee call. This is a couple cedar wax wings calling while scarfing berries in a small tree. And then there's the C-Call, S-E-E-E. C-C-E. calls are higher pitched and softer, more of a hissing whistle. Here are some sea calls being made

by a little flock of cedar wax wings. They're in a thicket of sumac plants at the edge of a prairie in Minnesota. The calls of bohemian and Japanese wax wings are similar to those of the cedar waxwing. Here's a flock of about 100 bohemian wax wings, also in Minnesota. They're making bzzi calls as they sit in an aspen tree. And here are some Japanese wax wings recorded near Shanghai, China. They're making what sounds to me like both types of call, bzee and sea. The name of the taxonomic family for wax wings is bombacility. Now, a word of advice, and I hope this would be common sense, never say the name of this bird family, bombacility, out loud in an airport.

unless you want to get tased by security and tackled to the ground. Nobody's going to believe that you were just talking about birds. Bombacilladee comes from the genus name Bombacilla. The genus is spelled B-O-M-B, like the thing that goes boom, followed by Y-C-I-L-L-A, Bombacilla. There seems to be some confusion among scholars about the origin of the word bombicilla. But after some research, my understanding is that it's supposed to mean silk tail in Latin. The Latin for bird lover's book on my shelf, however, would have me believe that bombacilla means silk hair.

See, confusion. So which is it, silk tail or silk hair? Who are we to believe? Is there some deep conspiracy at work here? Probably. But thankfully, there's a bit less confusion about. the relationship of wax wings to other songbirds. The family most closely related to the waxwing family is

Tilaganatidae. That's got a silent pee at the beginning, Tilaganatidae. These are the silky flycatchers. The Penapepla of the desert southwest in North America is in this silky flycatcher family. There are five other bird families that are closely related to the waxwing family. All of them are in the old world, and each contains a total of one species. These five relatively obscure families, lumped together with bombicillity and telogenatidae,

make up something called a superfamily. You know, a superfamily, like the characters in the Incredibles movie from Pixar. Just like that. Except, not at all. Birds in this super family, disappointingly, don't have abilities like super strength, invisibility, or eyes that shoot lasers.

The name of this superfamily is bombesoloidia. That's a mouthful I know. Bombosiloidia is a unique branch of the avian tree of life. A superfamily like this is a lineage that's more inclusive than a family, but less inclusive than an order. The ancestral bird species that gave rise to the bomba soloidia superfamily lived about 25 million years ago. somewhere in Eurasia. Eventually, its descendants diversified and some spread into North America.

Zooming back in to focus just on the birds in the Waxwing family, we see that all three species are found only in the northern hemisphere. The Cedar Wax Wing is a North American species. These guys live year-round in the northern U.S., but not. as far north as Alaska. Some populations migrate north into the boreal forests of Canada to breed. In winter, a bunch of them migrate to the southern U.S., Mexico, or Central America. Bohemian wax wings also live in North America, but this species range is much larger. It extends all the way around the northern hemisphere. Bohemian wax wings breed in northern Canada, Alaska, and northern Eurasia.

In the winter, they retreat to the south a bit to escape the most severe winter conditions. The Japanese waxwing has the smallest range of the three. It breeds only in southeastern Russia and a small part of northeastern China. In the non-breeding season, Japanese wax wings live throughout Japan, Korea, and a bit of eastern China. The three waxwing species do show some migratory behavior, as I've mentioned. moving north in summer and south in winter. But these birds are also well known for their nomadic wanderings. In the winter months, flocks of wax wings travel around searching for some sugar-packed berries.

Trees loaded with lingering, uneaten fruit crops are available only sporadically across the landscape in winter. So wax wings have to wander far and wide to find them. That's where the name Bohemian waxwing came from. from. These little vagabonds live a boho lifestyle, unconventional, and carefree. If they could, Bohemian wax wings would probably drive around together in a caravan of tiny Volkswagen buses, with flowers and peace signs painted on the side. No doubt the radios in the buses would be continually blasting Bohemian Rhapsody by Queen. These nomadic winter flocks might include just a handful of wax wings, or they

can be several thousand strong. Flocks can show up out of nowhere, even in places like deserts, agricultural areas, or suburban parks. As long as there are some trees or shrubs with berries, the wax wings will be able to find them.

The birds swarm in like locusts, gorge themselves until every last berry is gone, then they move on. They leave only devastation in their wake. Well, devastation and poop, I suppose. In terms of habitat, all three waxwing species tend to live near the edges of forests,

deciduous forests, coniferous forests, or woodlands. Even our gardens, parks, and old shrubby fields will do. As long as there are plants with fruit around, there's a good chance the wax wings will be there. During the summer breeding season, cedar and boho wax wings prefer to nest in trees where there's some water nearby, such as a stream, lake, or swamp. Turning our attention now to the conservation of wax wings. For once, it seems, the situation isn't especially dire. Both cedar and bohemian wax wings are still common species across much of their

respective ranges. These two species are estimated. to have worldwide populations in the tens of millions. And, luckily, their numbers are stable or even increasing in some regions. The Cedar Wax Wings Population Dynamics are the most well understood. The growth in populations of this species is likely the result of several things. One, the increasing number of fruit trees and shrubs in suburban and urban areas. This includes native plants, but also a lot of introduced,

ornamental plants. Two, the increase in forest edge habitat as forests are continuing to be fragmented by human activity. And three, the natural transformation of abandoned agricultural fields back into shrublands and forests. So all of that is true for the cedar waxwing. The Japanese waxwing, bombicilla japonica, isn't as well off. This species is in the near threatened category on the IUCN Red List. We don't have a good estimate of the Japanese wax wings total population, but it's thought to be relatively small, in part because its breeding range isn't all that large. The two biggest threats to the Japanese wax wing are habitat loss from logging and the wild bird trade. These beautiful birds are captured in places like China and then sold

in foreign markets. For example, over 5,000 Japanese wax wings ended up being imported to the European Union over the last 30 years. But who knows how many ended up in other markets? Removing that many Japanese wax wings from the wild could put this species at risk of a steep decline. Threats to wax wings in general include window collisions, collisions with cars, pesticides, and even poisoning by non-native plants. For example, dozens of cedar wax wings in the state of Georgia died from eating the berries of a plant called Nandina. This is a non-native invasive weed.

Nandina berries contain the poison hydrogen cyanide in low concentrations. But wax wings eat so many fruits all at once, Nandina berries can make for a terrible last meal for these birds. By now, you know that wax wings are frugivores, birds that specialize in eating fruit, especially berries. In fact, wax wings rely on fruit more than any other birds in the northern temperate latitudes, which is pretty remarkable. Birds of just about any other species in these regions would starve to death if they ate only fruit. Wax wings swallow whole berries, then poop out the seeds, so they are great at dispersing the seeds of plants.

Fruiting plants and wax wings have been co-evolving together for a long time. The plants provide tasty meals to the birds, and the birds help the plants propagate. It's a mutualistic relationship. Wax wings help to maintain and spread the vegetation of their own habitats. The cedar in cedar waxwing refers to the fact that, historically, these birds were known to eat boatloads of berries from Eastern Red Cedar, Juniperas, Virginiana. Apparently, it takes only about 12 minutes for an Eastern Red Cedar berry to pass through the gut of a waxwing, from beak to cloaca. Twelve minutes! Researchers estimate that, at that rate, these birds can eat about 53 red cedar berries per hour.

And get this, red cedar seeds that have passed through the gut of a wax wing have germany. determination rates 30% higher than seeds that weren't eaten. These days, all three waxwing species have a wider variety of fruits at their disposal, because people, right? Cedar wax wings also eat the fruits of dogwood, strawberry, apple, rose, mulberry, honeysuckle, and raspberry. They chow down on mistletoe, mountain ash, crabapple, hawthorn, and the list goes on. Being a specialist frugivou, requires some special adaptations. Sugary berries have pretty much no protein or fat. They're just filled with a bunch of simple sugars, like glucose and fructose.

Wax wings have physiological adaptations that allow them to survive on this low-protein, low-fat diet. But to get the nutrients they need from fruit, wax wings have to eat a lot of it. Many other frugivorous animals are limited by the time it takes their guts to to process their fruity meals. But we just talked about how it takes only 12 minutes for a berry to zoom through the bowels of a waxwing. These little buggers have short, simple digestive tracts that help them process food at a

breakneck speed. A wax wing doesn't have a true crop to store food the way many other birds do, but it does have a section of its esophagus that basically does the same thing. It expands to hold berries. As one berry is being squished around in the gizzard, the next few are in the chamber, in the esophagus, waiting to be processed. When fruit is plentiful, a wax wing will stuff itself full. Pretty much every spare space in its little body will be filled with berries, the stomach, the esophagus, all the way up to the mouth. The bird is practically overflowing with fruit.

Another diet-related challenge faced by wax wings is getting drunk, as in sloshed, plastered. Fruit can be fermented naturally by yeast in the environment. The byproduct of fermentation is one known and loved by humans around the world. Ethanol, aka alcohol, booze, hard liquor, sauce, hooch. There is some scientific evidence that wax wings have adaptations for dealing with intoxication from fermented fruit. They have relatively large livers, for example. One of the many functions of the liver is detoxification.

Wax wings also seem to be able to process ethanol more rapidly than some other bird species. But really, there doesn't seem to be much data out there yet. More research is needed. So, yeah, wax wings sometimes get drunk. They accidentally eat a bunch of booze-infused berries, then they get all silly. The birds stumble around and act confused. They have a hard time flying. Drunk wax wings say things to each other like,

I love you, man. No, I'm serious. You're my best friend. I love you. Then they pass out and just lay there, sprawled out on the ground. Local news stations love it when there are reports. reports of drunk birds. Here's a report from a station in Sacramento, California. Did you hear that? Drunk birds are totally a thing. Trending at 530, some rambunctious birds getting a reputation

in northern Minnesota. Police and Gilbert say they're responding to birds flying under the influence. Park rangers believe the birds are getting tipsy from eating fermented berries. Much like your drunk friend that maybe spends a night on your couch, it threw up and felt better, gave it some carbs and some water, and it did the flight of shame, Sure, this all sounds adorable and hilarious. You wouldn't think there would be any negative consequences to getting wasted on alcohol. But, unfortunately, there is a dark side for wax wings. Intoxicated birds can get injured or killed when they fall out of trees.

Flying under the influence is especially dangerous. Because wax wings sometimes smash into things like trees or windows. or they can simply freeze to death. But, I guess, wax wings have been dealing with the challenges of alcoholic berries for millions of years. On average, they're doing okay. Now, lest you think that these birds never eat anything but fruit, I should tell you that they do, in fact, supplement their diet with insects. In winter, it's pretty much all about fruit.

But in summer, there are many more insects available, and wax wings will take advantage of this source of protein and fat. Flying insects like mayflies and dragonflies are caught mid-air. Wax wings will also pick insects like beetles off of leaves and twigs. The tables sometimes turn and wax wings themselves become the prey. Their primary predators are bird-eating raptors like Merlin, sharp-shinned hawk, or Cooper's Hawk. And here's a crazy story.

One day, a bunch of cedar waxwings were drinking water at the edge of a stock pond in Texas. There they were, peacefully as ever, sipping water. But little did the birds know they were being watched. Two bulbous golden eyes protruded just above the pond's surface. Suddenly, a green beast exploded out of the water, its enormous mouth wide open. It was a bullfrog. The frog grabbed the nearest wax wing in its jaws and swallowed it whole. True story. In this particular crime scene, researchers found multiple bullfrogs with bellies full of wax wings.

Insane. Frigan bullfrogs, man, they eat everything. There are some other birds that aren't predators of wax wings, but they might qualify as enemies. Northern mockingbirds, for example, like to stay. claims on fruit trees in the fall and winter. A mockingbird fiercely defends its tree from other berry-munching birds. It can successfully kick the butts of one or several invaders. A mocking bird will sometimes even kill a wax wing by knocking it to the ground and stabbing it with its beak. I guess he wasn't kidding when he said, You come near my tree, I kill you.

But then here comes a ravenous flock of 200 wax wings. This cloud of fluttering, silky smooth beauties descends on the mockingbird's fruit tree and all is soon lost. The aggressive mockingbird can't win against these overwhelming numbers. He just has to watch in shocked disbelief as his precious horde of berries gets swallowed whole. 12 minutes later, insult is added to injury as each berry gets ejected as waxwing poop. Our last section today is about breeding in wax wings. These birds are socially monogamous, a single male and female pair up to raise a clutch or two every breeding season.

Nature photographers love to get shots of waxwing courtship behavior. It's pretty darn cute, I have to say. Waxwing courtship goes something like this. A male and female perched on a branch hop towards each other. They hop forward, then away, then forward again. They touch bills sometimes, looking like they're kissing. The male usually offers a small edible item to the female, like a flower petal, bug, or berry. She takes it, hops away, then hops back. Then she gives them. the male his little gift back. They pass the item back and forth repeatedly, a dozen times or more. This courtship hopping display usually ends when the female finally eats the item offered

by the male. I'll put a link in the show notes to a video of this courtship behavior between Cedar Wax Wings. Wax Wings in general breed relatively late in the summer. They do this so that there's plenty of ripe fruit available when their chicks hatch. A bonded pair of wax wings looks for a suitable nest site together, but it's the lady wax wing who makes the final decision. The spot is usually at a fork on a horizontal tree branch. The female builds the nest, mostly on her own, but the male will help bring construction material.

It's a cup-shaped structure made of grass, twigs, cattail fluff, horsehair, and other such materials. After about five days, the pair of wax wings might have made over 2,000 trips to find nesting material, or maybe fewer trips if they can pilfer material from the nests of some neighboring birds. Eventually, there are about five eggs in the nest, being incubated by the dutiful female. The male, meanwhile, brings her food like he's working for Uber Eats or Instacard or something. When he's not out looking for food, the male perches on a high branch out in the open, where he can survey his surroundings. He acts like a sentinel, protecting his mate and young from danger.

After maybe a couple weeks, the chicks hatch. As you can imagine, these growing babies need protein and fat in their diet. Indeed, mom and dad feed the nestlings insects for a couple days. after that it's fruit fruit and more fruit how about a side of fruit with your fruit and for dessert i don't even need to tell you that it's fruit most other birds in temperate regions feed their chicks lots of protein rich food like insects not just for a couple days but for weeks or months but not wax wings in fact bombissolids the three waxwing species are unique in that they're the only birds living outside the tropics that feed their chicks almost exclusively fruit. The baby wax wings must have physiological adaptations for growing muscle and bone and all of that without very much protein.

Brown-headed cowbirds are brood parasites that sometimes lay eggs in cedar waxwing nests. What's a brood parasite, you ask? Well, how about you go listen to episode 12 of this podcast? The title is Brood Parasites are Devious Birds. Anyway, Cedar Wax Wings are pretty good at recognizing and rejecting cowbird eggs. They yell, It's a trap! Then they toss the egg unceremoniously out of their nest. But sometimes a nesting pair of cedar wax wings don't see through the ruse.

They end up accepting the brown-headed cowbird egg as one of their own. The cowbird chick hatches and starts begging, demanding to be fed. Sort of like the giant carnivorous plant in the little shop of horrors. But the wax wings feed the cowbird chick pretty much nothing but fruit. So guess what happens? In this situation, the cowbird chick almost never survives. Unlike the baby wax wings, the cowbird chick doesn't have the physiology to survive on a diet of sugary, fruits alone.

Young wax wings fledge after two to three weeks in the nest. The parents keep stuffing their fledglings with berries for maybe another ten days. But then mom and dad say bye-bye and split. Well, I guess the Japanese wax wings would probably say, Sayonara. But don't feel too bad for the wax wing youngsters abandoned by their parents. They'll find some other immature wax wings and form flocks. They all stick together as they face their first winter.

The oldest wax wing ever recorded by ornithologists was seven years old. But most of these birds aren't so lucky. Research has shown that in some populations, more than half of the wax wings don't survive from one year to the next. They face dangers like hawks, selfish mocking birds, poison berries, and apparently even bullfrogs. many other songbird species tend to return to the same breeding sites where they were born or to where they bred successfully in seasons past i mean it worked before right

but wax wings are less likely to have any such fidelity to where they were born or to where they bred in the past this is probably another example of waxwing biology that reflects their fruity diet at any given location fruit availability is unpredictable from year to year. So it makes little sense to return to the same breeding site. Wax Wings think it's better to wander far and wide. Get together in a flock with your peace-loving pals and scour the land for that next patch of sweet, sweet berries. After listening to this episode, I hope you'll agree that wax wings, birds in the family, bombacility, are the bomb. But maybe you already felt that way. Oh, and don't say that in the airport. Wax

wings are the bomb. Thanks for taking the time to learn about birds with me today. You could have spent that same time staring at a wall or talking to your garrulous co-worker on the phone. Life is short. Your time is valuable, so I really appreciate it that you're here with me. I also really, really appreciate my supporters on Patreon. Their monthly contributions are of big part of what makes this whole thing possible. A special shout out to my newest patron, Alan Chang. Hi, Alan, and thanks so much for the generous support. Anyone can become a supporter of this podcast.

Well, anyone with a little extra cash, that is. If you fit that description and are wondering how you can help me out, just check out my Patreon page over at patreon.com slash science of birds. And if you have something you'd like to share with me, you can reach me by electronic mail. Maybe you have a comment about the podcast, or you want to tell me the name of your car, or about some regrettable things you've said to your friend

while drunk on fermented berries. In any case, my address is Ivan at Science of Birds.com. You can check out the show notes for this episode, which is number 65, on the Science of Birds website, scienceofbirds.com. I'm your host, Ivan Philipson. Thanks again for being here, and I'll catch you in the next episode. Peace.