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Archive for the ‘birds’ Category

hooded vs carrion crow

In Europe, there are crows. The most famous of which is the carrion crow, which looks and behaves quite like the American crow.  It is usually black, fairly omnivorous, and it often regarded as an agricultural pest.

At one point, it was believed that carrion crows existed in two distinct phases, the common all black form, which is common in Western Europe, and the phase that is marked with gray on the neck and body.  This form exists in the northern parts of the British Isles, where it has been called the grey grow, the hoodie crow, or the hooded crow. This form is found in Northern Europe, Central Europe, and the Middle East.

However, ornithologists began to notice that where their ranges overlapped, it was quite unusual to see hooded crows paired off with black carrion crows, but the traditional taxonomy still thought of the hooded and black forms as being distinct phases of the same species.

Because the two forms were rarely seen mating or paired off, it was decided to call the carrion crow and hooded crow distinct species, and this is the current understanding. The hooded crow is Corvus cornix and the carrion crow is Corvus corone. But the two birds are otherwise quite similar in terms of ecology, vocalizations, and general phenotype. All that really separates them is the coloration.

Scientists that surely there was a rather deep genetic divergence between the two species, which is why there is a species barrier between the two forms of similar crow.

However, when the genomes of carrion and hooded crows were sequenced, it was revealed that they were almost identical.

Less than .28 percent of the genome varied.  That variance was related to the fact that carrion crows have gray plumage on their neck and torso.

But that little variance is enough to create a species barrier between the carrion and hooded crows. Birds are highly visual, and when young crows imprint upon their parents, they imprint heavily upon what they see. If a young crow is raised by parents that are gray hooded, they will look for mates that are gray hooded. IF their parents are all black, they will look for mates that are all black.

However, it has also been suggested that these crows look for mates that appear not to have aberrant mutations, and this keeps the crows looking for mates that generally look like those belonging to their general family group and social circle.

Whatever the case, we have two very closely related species that do not hybridize. They probably became distinct during the heavily glaciation cycles of the late Pleistocene. One form evolved a gray hood and one evolved an all-black form. Maybe founder effect is the only real reason for this difference in plumage, for this difference in plumage is awfully random.

But that difference in plumage color is enough to create a species barrier, which, if it holds, will lead to greater and greater speciation between hooded and carrion crows.

This discovery about crows is quite interesting for what it tells us about dog taxonomy. Domestic dogs and wolves live together over a broad swathe of Eurasia, and for many centuries, dogs and wolves were regarded as distinct species. However, we have recently found that there is an extensive gene flow between Eurasian gray wolves and domestic dogs across Eurasia, and this gene flow is so significant that the majority of Eurasian gray wolves are estimated to have some relatively close dog ancestry.

Carrion and hooded crows have a clear species barrier that is likely only going to intensify as the two lineages continue to diverge with very limited gene flow. Dogs and gray wolves are not experiencing such a species barrier. Indeed, it looks like the gene flow between dogs and wolves is only going to increase as wolves move into human-dominated lands in Western Europe, and the Eurasian dog population continues to increase along with the human population.

So here we have two crows that are diverging, and the wild and domestic forms of Canis lupus that are continuing their gene flow.  Closing down gene flow is a major part of speciation, and the crows are clearly on their way.

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tristan moorhen

Off the southeastern coast of Africa, the British Empire still holds onto some islands. The most famous of these is St. Helena, where Napoleon lived out his final days in his second exile thousands of miles from France and Europe and any trouble he might want to cause.

On two of these islands, though, a taxonomic controversy has brewed for decades. On Gough Island and Tristan da Cuhna, insular forms of moorhen (also known as gallinules in much of the US) existed.  They were smaller than the common moorhen, and they possessed shorter wings. In this way, they exhibited both insular dwarfism, a common trait of organism evolving on isolated islands, and the loss of flight that sometimes happens when birds evolve without selection pressures from predation to ensure flight in the population.

The moorhens on Gough Island, nearly 400 miles away, were quite similar to those on Tristan da Cunha, and in the 1950s, some Gough island moorhens were introduced to Tristan da Cunha.

These Gough Island birds did quite well on the new island. where an estimated 2,500 breeding pairs now exist. However, because these birds were introduced from Gough Island, they are not regarded as native and are not protected.

Traditionally, experts have regarded the Gough and Tristan moorhens as distinct species. The Gough species is called Gallinula comeri, while the extinct Tristan species is called Gallinula nesiotis.

However, over the years, it has been suggested that the two were of the same species, and the introduction of the Gough species was actually a reintroduction.

Not many DNA studies have been performed on these birds, but the most notable is Groenenberg et al (2008).   This study examined samples that have been collected over the past two centuries, including a specimen from Tristan da Cunha that was collected in 1864.

The authors found that the two forms were roughly genetically distant from each other as different subspecies of the common moorhen. Indeed, if one were wanting to keep the common moorhen a monophyletic species, one would be forced to include these two insular forms as subspecies of the common moorhen.

The authors found that the Gough moorhen had replaced the Tristan form, and they were different taxa. However, because their genetic difference was equivalent to the genetic difference between some common moorhen subspecies, the authors proposed that these two forms be regarded as subspecies, which they propose as Gallinula nesiotis nesiotis and G.n. comeri.

These birds are most closely related to African and European moorhens than they are to South American ones,

However, the debate gets fairly interesting here because the South American common moorhens are typically considered subspecies of a quite wide-ranging species. When the authors performed their research, the common moorhen was believed to have existed in Eurasia, Africa, and the Americas, but in 2011, the New World population was given full species status, which is usually called the common gallinule. Taxonomists fixed the paraphyly of the common moorhen by creating this new American species (Gallinula galeata).

But this study does not fix the controversy about the moorhens on Tristan da Cunha. Even if the Gough and Tristan populations constitute different subspecies, a real debate can be made as to whether the birds on Tristan da Cunha represent an introduction or a reintroduction.

And this is where the subjectivity part of taxonomy sets in. If the Gough subspecies behaves in the ecosystem in an equivalent way to the extinct Tristan subspecies on Tristan da Cunha, then one could just make the argument that the arrival of these birds in the 1950s was a reintroduction. If they behave in a fundamentally different way from the extinct Tristan birds, then they were simply introduced and certainly don’t require any special protections as a native species under the law.

But the subjective part is where to draw the line between being fundamentally similar or fundamentally different. Yes, the Gough subspecies is genetically different, and it may have some attributes that cause it behave just slightly differently from the extinct Tristan subspecies.

However one answers this question, one should keep in mind that it cannot answered so easily.

This debate is quite strong, not just in gallinules and moorhens, but a big debate exists within some quarters as to whether the feral horses of the American West represent a rewilding from the Pleistocene. Horse evolved in North America and then became extinct at the end of the Pleistocene, but a huge debate exists on how to classify the various late Pleistocene horses. They may have been a single species that was very close to the modern horse. In which case, the feral horses of the American West might be argued to be rewilding population. A more recent study on cheek teeth and ancient mitochondrial DNA of these horses revealed there were three species of horse in North America at the end of the Pleistocene, one of which was very close to the modern horse.

But the Pleistocene ended around 10,000 years ago, and the ecosystems that maintained horses on the range no longer exist in the same way. In this case, one could not honestly say that this was a rewilding. It would be an introduction. (That’s where I stand on the horses as native wildlife controversy.)

However, I’ve often thought about what would happen if we somehow got greater prairie chickens to thrive on the East Coast once again. A subspecies of the greater prairie chicken called the heath hen once ranged all the way down the coast from New England to Northern Virginia. It was a colonial staple, and it was hunted out of existence.

The last population of these birds lived on Martha’s Vineyard, and the last one died in 1932. Attempts have been made to introduce greater prairie chickens to the island in an attempt to restore something like the heath hen to the island, but these attempts have fails.  If such an attempt were successful, it would be very much like the replacement of the Tristan moorhen with the Gough subspecies.  A debate could be had as to whether it was was reintroduction or not, but at least it would be something.

So the story of the moorhens on these South Atlantic islands tells the story of a controversy. It is one that rages in the conservation community all the time. Can you restore an extinct subspecies by introducing another related subspecies?

That answer is never going to be fully black and white. Ecological as well as taxonomic considerations have to be examined. Otherwise, someone could easily make the argument that wolf reintroduction and conservation are silly ideas, because, well, domestic dogs are everywhere. Dogs are a subspecies of wolf, so they just replaced them.

So this controversy will rage hard as we try to deal with this nasty extinction mess. We don’t always have all the answers. We don’t always have the best solutions. But we need to think it through carefully. It’s all gray or grayish.

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mallards

Common mallard = gray wolf

Domestic mallard (Pekin, Cayuga, Rouen, Khaki Campbell) = domestic dog

Black duck = Eastern wolf

Mottled duck  = red wolf

Mexican duck = coyote

Laysan duck = Ethiopian wolf

Hawaiian duck = African golden wolf

Gadwall= Golden jackal

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drake black duck

So if you thought the gray wolf species complex is controversial, it mirrored in another charismatic, widespread species.

I used to be quite into domestic ducks. My preferred variants were all domesticated Eurasian mallards, and I regularly encountered wild mallards at the various parks I would frequent in Morgantown, West Virginia.

I have no problem considering Pekins, Cayugas, Khaki Campbell’s, and Rouens just domestic variants of mallard. Most domestic mallard varieties cannot fly, and many lack proper brooding instincts and could never really exist in the wild. However, domestic duck genes do get into the wild mallard population every so often. So in this way, domestic ducks are to mallards what domestic dogs are to gray wolves.

But the analogy gets even more interesting.  There are endemic mallards in North America that are often regarded as distinct species, and most experts would regard them as distinct species. However, they could easily be thought of as regional variants of what is really a mallard complex.

The most common endemic North American mallard is the black duck. The black duck is a large mallard that behaves almost exactly like the more common form. However, the drakes never develop the green heads or chestnut breasts. They never get that ornate gray penciling on their plumage. They are heavily mottled, rather dark large mallards.

Most authorities regard this creature as a distinct species, but a good case can be made that American black ducks are a regional form of mallard. They live over Northeastern and Midwestern states. They breed extensively in Eastern Canada and the Northern Great Lakes.

One hypothesis is that these ducks are descended from an early radiation of the ancestral mallard that adapted to living in bodies of water surrounded by extensive forests. Because there was so much predation in those areas, the ducks had a strong selection pressure never to evolve the ornate plumage of the more typical mallard.

These ducks evolved into a distinct population from Northeastern Mexico to Florida, which is called the mottled duck. The mottled duck is usually considered a distinct species as well.

And in deeper into Mexico, there is the Mexican duck, which is probably derived from black duck population.

One weird thing, though, is that mallards and black ducks really do not recognize much of a species barrier. Indeed, the genetic difference between black ducks and mallards appears to be decreasing.

Maybe a better reading of black duck taxonomy is that black ducks just represent a form of mallard that adapted to living in high predator density forests, and now that the forests have been opened, the more open country forms of mallard in which the drakes have ostentatious plumage have invaded their range.

And they have started to hybridize significantly.

Most waterfowl experts would disagree with me on this question, but the truth is the molecular work on mallards and their relatives is far behind canids. And yes, we do know that lots of Anas ducks hybridize. Hybridization itself is not a very good species indicator within these species, but if it is as significant as it is between black ducks and mallards, then we have to reconsider our classification.

I would love to see full genome comparisons of the various ducks in the genus Anas. We need to get a better idea of when all these various ducks diverged from a common ancestor and get a full handle on how much hybridization has happened.

Gadwalls are also somewhere in this mess. They might be an early offshoot of mallards that adapted to truly open environments, but I would not be surprised if their hybridization was at a level comparable to that of black ducks and mallards.

So we need more molecular work on these ducks. Their evolutionary history has quite strong parallels in the gray wolf complex, including their wide distribution, lots of hybridization between populations, and domestic form that casts a few genes into the wild population every once in a while.

The only way to resolve these issues is to have comparisons of full genomes. My guess is that we will someday, but until now, we’re still basing species on mtDNA samples and very limited genetic markers.

 

 

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Cock of the Walk

cardinal audubon

Spring comes in softly at first. Then, it rushes in hard and warm, like water gushing from the faucet into a dirty sink.  The birds start their singing when it starts in softly. The cardinals are among the first to lift their voices high among the skeleton trees. The testosterone flows hot in their red-feathered forms, and they begin to set out their breeding territories for the year.

All winter, they have moseyed morosely with mixed flocks of hens and cocks. They have flitted at the feeders as comrades against the cold and the hunger, but now, the primal pursuits of carnality take over. And the cockbirds turn violent against those former friends, and by the time, the first warm days of April come slipping along, they have set up their fiefdoms. And all through the warm months, they will patrol their lands, ready to do battle against any interloper.

This year, a particular male cardinal, all resplendent red, chose a piece of territory near a fine home with nice English garden. It also had a well-built garage.  That garage possessed a large window and along the wall where the window was located was was well-manicured flower-bed.

The cardinal had done a good job driving out all the bachelors, poachers, and Lotharios from his land, but every time he inspected that part of the territory near the garage, the bright red form appeared in the window. And oh it would enrage the cock cardinal!

How dare that poaching lowlife appear on his land! How dare he!

And the cardinal would attack the red form in the window. He would think that his orange beak would lay a hard blow against his rival feathers, but each time he banged into the window.

And he would get angrier and angrier. He would spend hours fighting the phantom bird in the glass. He would sometimes tire and fly along the walk leading to the garage and mutter little cheeping sounds at its rival.

He was the cock of this walk. No one else will ever be!

The owners of the house would have thought this whole display rather charming. However, during all those hours of fighting his rival in the reflection, the male cardinal dropped copious white feces all along the walk.

The woman of the house hated cleaning up the bird poop and regularly let her husband know about her displeasure. She wanted something done and done soon.  A shotgun could solve all their problems.

But the man of the house was more circumspect. He liked living where cardinals could flit and sing all summer, and further, he was fully aware of a federal law protecting songbirds.

So he tried setting out scarecrows in the flowerbed and along the walk. And for a day, they kept the male cardinal from coming in to war and poop.

But those primal urges were that strong, and the male cardinal returned to give up a good fight.

He fed his mate and his growing chicks, but every day, he had to spend hours fighting his rival in the window. And the feces kept piling up.

One day, the man rose from the house. He cradled a 20-gauge rabbit gun in his right arm. He waited until the cardinal gave him a clean shot, and nothing was behind the bird. And then he raised his gun. And broke the federal law.

And the red bird fell hard and lifeless to the ground. The man picked up the cardinal and threw him in the trash.

No evidence of the crime was left. It was just over with a single shotgun blast. No one knew any the wiser.

Modern man likes to live near nature, but even in the most banal of conflicts, nature must yield to man’s desires.

No concession could be given to the cardinal. His chicks in the woodland starved. His mate found a new lover among the Lotharios, and the new mate was not as aggressive about pecking at his rival in the garage window.

And so the summer went on. The cardinals sang and caught grasshoppers and ate summer wheat and August corn.

And their lives went on in the wild, minus the cock of the walk that dared to fight his own reflection in the window.

 

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dusky grouse hen

Dusky grouse hen.

Hybridization between animal species is a topic that has long fascinated me. I’ve been looking at various animal hybrids over the years, and some are really quite shocking. Marine mammals produce all sorts of weird hybrids, as do birds, and in it is in the avian world that I came across the strangest hybrid.

Only a few of these hybrids have ever been reported, but a few hybrids between “blue grouse” and common pheasants have been reported.  I should note that these “blue grouse” and pheasant hybrids have mostly been documented before the molecular revolution in biology and no DNA studies have ever provided proof that these weird birds were indeed hybrids between the two species.

Also, these hybrids were described before the “blue grouse” was split into the dusky and sooty grouse. The dusky and sooty grouse are estimated to have last shared a common ancestor 240,000 years ago and have been given distinct species. The sooty grouse (Dendragapus fuliginosus) is found in conifer forests along the Pacific Coast from the Yukon to California, while the dusky grouse  (D. obscurus) is found at similar forests in the interior mountains of the West.

These grouse are highly specialized to life in conifer forests. The breeding behavior of both species of grouse involves the cockbirds hooting from way up at the top of big conifers to draw in hens.

Compare this bird with the common or “ring-necked” pheasant (Phasianus colchicus). This is an introduced gamebird that, although found in Western Europe, is native from the Caucasus into East Asia. This a grassland species that has social and breeding behavior that is quite similar to domestic chicken. Indeed, these birds are quite closely related to the jungle fowl of South Asia, and sterile hybrids between chickens and pheasants are not uncommon.

The common pheasant is a grassland specialist. This bird was heavily introduced to the Midwestern and Eastern US as a gamebird, and now that the forests have largely taken over vast swathes of farmland, the birds are far less common. For example, West Virginia now allows only a single male pheasant to be taken every day during the pheasant season, while Ohio allows only two for the daily bag limit.

So pheasants are a creature of the grassland and dusky and sooty grouse are creatures of the big conifer forest, it is quite surprising that these two birds would ever encounter each other, much less make a hybrid.

One hybrid was described in 1955. It was likely the result of game farm pheasants crossing with a dusky grouse in Eastern Washington State:

hybrid blue grouse and pheasant

So by 1955, four these hybrids have been documented. However, this discovery was documented at roughly the same time Watson and Crick discovered DNA, and no one had any way to confirm this hybrid origin using molecular techniques. I have not heard of any other hybrids between these two species since this one from Spokane County, Washington.

These forest grouse and these grassland pheasants are so distinct from each other. However, I do know from my own observation of gallinaceous birds that the males of these species are pretty amorous. They will try to hump whatever they can, and a female pheasant sort of looks a lot like a dusky grouse hen.

My guess is this specimen described in the 1950s was the result of a male dusky grouse mating with a farmed pheasant. Only one poult managed to hatch out from the mating, but the poult imprinted upon its  pheasant mother. When it went looking for others of its kind, it wandered over to pheasant farm and tried to join what looked and sounded like its mother.

These hybrids are not something that one would expect to see in nature, but because man is constantly breeding and stocking pheasants to fit the needs of hunters, there could always be a chance for some intrusion of the pheasant into what is really much more suitable sooty or dusky grouse habitat.

Grouse and pheasants are not that closely related to each other either, but avian hybrids have been documented between species of quite unrelated lineages on a fairly regular basis.

 

 

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The Last Covey of Quail

bobwhites (2)

They came marching through the dead stalks of corn, filling the air with their eerie little noises that denote their comings and goings to anyone who happened to listen. They were of the bobwhite tribe, and this was their last redoubt in this little rugged hilly country n middle of nowhere in West Virginia. There were 9 of them, three cockbirds and six hens, and they were living the best they could in the land of the little corn patches and brier patches. They were not the land of grass and grain, but in in the land of encroaching woodland, the stooping hawk, and the wily nest-raiding raccoon.

A man with a shotgun and stronger taste for squirrel meat than wild poultry heard their rustlings and eerie calls, and knowing that, despite their rarity, the state allowed a quail season, he decided to creep along the cornfield to flush the birds into the air.

The birds shot out of the corn like living confetti released from a can, and the 20 gauge blasted three times. Each wad of shot hit its mark,  and the birds fell, two cockbirds and a hen. The man gathered them up and put them in his game bag, then began to mosey his way to the hickory stands on a distant ridge, where the gray squirrels squacked and scurried and a hunter’s shots were sure to bring home a limit of game.

But what he didn’t know is he shot out the last covey of bobwhites that ever would grace these hills. All the old farmers knew these birds. They would set out to cut their hay with scythes, and the birds were all around their hayfields, moving in great companies of paired off hens and cockbirds and chicks of the year that varied in size from slightly larger than bumble bees to the size of sparrows.

But the birds evolved for the farmfield, and when the farm boys all found good jobs in places like Detroit and Cleveland, no one came with scythe or tractor upon the land. The hayfields filled with multiflora rose, then Virginia and white pines began to pioneer their way upon the scene, quickly followed by quaking aspen colonies.

And the hayfields and pastures returned to forest, not the forest primeval of which we so romantically dream, but the secondary growth that is all viny and stunted. The greenbriers and the multiflora rose created a paradise for ruffed grouse for a time, but a total martian landscape for bobwhite quail.

And so the decades of disuse took their toll, and the forest conquered the pasture and hayfield. It was an ersatz reconquista, for yes, the forest is what stood on the land before the Europeans came was full of mighty oaks and chestnuts. But now the spindly secondary growth took over the scene.

Each year, the calls of the quail became fainter and fainter to the old farmers who eked out some semblance of survival upon land, and it wasn’t long before most of them thought the birds were gone. A few enterprising souls complained to the state about the continued liberal hunting season of the birds, but the state never would take action. The war against the woodland’s advance was simply not worth fighting, and there were well-funded bird dog trialers who set out pen raised bobwhites for their sport. A ban on their hunting would interfere too much with this constituency, and so nothing was done.

So the shots rang out over the cornfield, and three birds fell from the sky and out beyond their mortal coil. The man roasted the quail breasts in his oven, and he thought long and hard about nice November nights, when he’d eat some quail breasts for dinner and then he’d step out on his back porch and smoke a cigarette and stare up into the infinity of stars above. He would wonder a bit about the big questions of existence. The smoke would fill his lungs and shoot out his nostrils, and he would feel at peace in the cold, crisp stillness of a night before the coming winter.

But now he felt as if he were eating a relic from a time gone by. He savored the quail flesh, and be began to worry if these might have been the last ones to grace his plate.

And then the cold winter came, and the chill winds rushed down from Canada and froze the land for six hard weeks. The five of the quail died of horrific starvation, and the survivor, a demure but tough little hen, made it to see the greening of March and April.

But a lone bird doesn’t last long, and one night, a barred owl staked out her resting place, then stooped down from a little walnut tree and carried her off a nice morsel of night fare.

And so the quail’s little marching songs no longer pierced the grass and the corn patches. The “bobwhite” call never sung out around the old hayfields, where this call and the sound of scythes being sharpened were so quintessential of the farmer’s haycutting as to be its sound track.

The land went from big woods to farmfield then back into woods again.  Those creatures whose fortunes soared when the land was cultivated saw their fortunes collapse once the constant tilling and haycutting ceased.

The old farmers spoke with nostalgia of the sharpening of scythes and the twitter of quail, as if it always been that way, but these old farmers lived only the life time of men. And they could not have seen the world before their forebears came and opened up the land and grazed cattle and sheep and planted big stands of corn.

Their mind’s eye could only see what they knew as children and young men upon the land. They could not see the days when the forest was full of big trees, and the descendants of that Siberian colonization hunted wild game. They grew some corn and squash in the river bottoms, but they left the rugged hills to stand as big woods, parkland for the bison, elk, and bears that were their meat and hides.

And so the last covey of quail died out in the hills, but it was not the shots that killed them in the end but the simple decades of disuse that allowed their land pastures and fields to go into forest once again.

To have an ecological view of the world, one must not fall into the trap of the old farmers, who could only know what they had seen in their lives, but one must think of the way land shifts from use to disuse, how one can see things like the forces of economics driving hard against the way things are into what surely must be.

And so it was that the people of the hills learned to shoot squirrels and grouse on cool November days before the big rifle season for deer came rushing in with Thanksgiving week. A few of the old ones would reminisce about the big coveys of bobwhite, but the young ones never paid that much attention. They would never know the sound of a scythe upon the tall orchard grass on a sultry day in late June that would be accompanied by the eerie calls of quail in the tall grass.

Their mind’s eye was trained upon the woods, the yapping squirrel dogs and the solid setters. They no longer felt that connection to the land of farms, but instead, thought of themselves as truly sylvan dwellers.

Each epoch and era twists the winds of existence for each generation, and so no one alive in twenty years will miss the quail.  But as the forests grow more mature, the land stops being such a great paradise for ruffed grouse, and maybe that will be the thing that the present generation will feel a nostalgic sorrow for when their drumming ceases in the aspen.

Maybe we will know the full story of the succession of the land from field to forest. Maybe a more ecological view point will be more commonplace by that time.

But we are a remembering species. Nostalgia is our great disease, and so long as we feel peace and comfort with some association, that association will be soft and deep and balming to our spirit.

That is the story of our species, not the story of quail, but it is what we are.

We just have to be aware of its power, and its powerful beguiling.

 

 

 

 

 

 

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