Wild Swans

Writing adequately about swans and their place in mythology and literature would take a very long time indeed.  We started the process early in the history of this blog when we began our series about bird sex.  (Part I, Part II, Part III)

Today, while waiting for the end of winter, that season during which the constellation Cygnus the Swan is not flying up the Milky Way high overhead, we turn to Edna St. Vincent Millay’s poem of a woman inspired by wild swans to open her heart to all the myriad joys of life.

Wild Swans

I looked in my heart while the wild swans went over.
And what did I see I had not seen before?
Only a question less or a question more:
Nothing to match the flight of wild birds flying.
Tiresome heart, forever living and dying,
House without air, I leave you and lock your door.
Wild swans, come over the town, come over
The town again, trailing your legs and crying!

Edna St. Vincent Millay

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Photo Credit: Ginger Holser, WDFW photos.

Turkeys

Wild Turkey

Benjamin Franklin famously believed that the national bird of the United States should be the wild turkey.  Of course, he also thought the rattlesnake would be a good symbol for the new country; because this is a bird blog, we’ll let that go.

In a letter to his daughter Franklin wrote about the bald eagle,

He is a Bird of bad moral Character. He does not get his Living honestly. You may have seen him perched on some dead Tree near the River, where, too lazy to fish for himself, he watches the Labour of the Fishing Hawk; and when that diligent Bird has at length taken a Fish, and is bearing it to his Nest for the Support of his Mate and young Ones, the Bald Eagle pursues him and takes it from him.

On the other hand, Franklin asserted,

For the Truth the Turkey is in Comparison a much more respectable Bird, and withal a true original Native of America . . . He is besides, though a little vain & silly, a Bird of Courage, and would not hesitate to attack a Grenadier of the British Guards who should presume to invade his Farm Yard with a red Coat on.

Franklin was right about the turkey being a native of North America.  It has been here a long time. Because of its large size and historical use as human food, the turkey has a good fossil record.  Fossils have been found as far back as the Miocene and the Pleistocene in North America. Archeology established long ago that many subsistence cultures ate them.

Female Wild Turkey with chicks

Hunting them must have been a challenge to those early hunters. Franklin aside, the birds are extremely wary; no wild turkey would have attacked a British Grenadier.  But it would have seen and heard that Red Coat coming from miles away and fled.  Wild turkeys possess keen eyesight and exquisite hearing which makes them hunting challenges even for their primary modern predator, humans.  Males prefer running away; females, flying.  Both can fly and at speeds up to 50mph.

That turkey in your kitchen for this Thanksgiving is a pale imitation of the real thing.  Because of the popularity of white meat — white because it is different muscle with less ability to store oxygen than dark muscle — your turkey was bred for a large breast.  In fact, domesticated turkeys raised for food have such large breasts they are incapable of mounting females for the cloacal kiss.  Instead the males are artificially manipulated and then milked for their semen which is then injected into the females to fertilize their eggs. Confined to quarters, these domesticated turkeys are tricked by artificial light into breeding year round so that the supply, especially now, is adequate.  Far too heavy for flight, it could never have escaped a British soldier.

But even though that Broad-breasted White Turkey you cut into this Thanksgiving is not the same as his wild, shrewd cousin, you partake of a North American tradition far older than Thanksgiving.

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If you need any help carving a turkey, here is a video of a pretty good way to do it.

Displayers of the Purple Sage

The governor of Wyoming, unlike the federal government, is worried about the Greater Sage-grouse.  The mad dash to sell and lease the West to the oil and gas companies, frenetic for the last seven years, has reached an even more frenzied state as the Bush Administration winds down.

Lewis and Clark wrote about the Sage-grouse in 1805, back when it was abundant on western prairies.  That was before conversion of the prairie to agricultural uses and mineral extraction.  Millions of acres were stripped in order to grow wheat and potatoes. Millions more were stripped to make the land safe for cattle.  Sagebrush, almost as nutritious as alfalfa, contains toxins which kill bacteria in the stomachs of cows which can result in death. Cattle, unlike Pronghorn Antelope, did not co-evolve with sagebrush.  Antelope thrive on it.  Their ancestral range shrunk along with that of the Sage grouse and Native Americans who used sagebrush to stop internal bleeding and to rid themselves of internal parasites.

Cities required yet more sagebrush land.  As a result of all this human activity, sagebrush is dying and so is the Sage-grouse.  We’ve denuded an area the size of Europe of its natural cover.  If he were writing today Zane Grey would name his most famous novel, Riders of the Long Gone Sage.  What little sagebrush habitat is left overlies deposits of natural gas and oil.  Exploration, drilling and extraction disrupt the habitat and its occupants even more.

Sagebrush

The Greater Sage-grouse is the largest North American grouse and is famous for the mating displays of the males.  When the spring mating season comes, their esophagi enlarge as much as 50 times, apparently the result of large doses of testosterone.  They expand and collapse their esophagi pouches making noise to attract females.  The males gather on breeding grounds known as leks to strut their stuff as you can see in this video.

The females wander through the leks and select males.  Actually they select very few males.  In one study two males copulated with 76% of the available females.  Because mating, a cloacal kiss, takes only few seconds, males may mate as many as 20 times a morning. One male was caught by a scientist copulating 169 times in one season.  Less successful males hang around, apparently hoping that the successful males will tire, leading other females to select them.  (“The spillover effect,” according to one scientist.)

Mostly this activity occurs around sunrise during springtime.  Golden Eagles learned about this.  Now they wait, up in the eastern sky for the strutting to begin then swoop down out of the sun attempting to grab a bird. The most successful males are in the most danger because they keep strutting after the other males and females have gone to ground.  A little testosterone is a good thing; a lot of it can get you in trouble.

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The film and the photos, except for the last one, come from Dr. Gail Patricelli of UC Davis.  You can read more about Greater Sage-grouse at this Audubon site.  If you want to weigh in on habitat protection the Audubon Society has a form letter you can send to the BLM, although it is always better to write your own.

“Y” Chromosome Day

Today is the greeting card industry’s celebration of the “Y” chromosome in human beings. Also known as “Father’s Day,” it is a day, in my family anyway, where I am invited to take my kids out to lunch or dinner. Which got me to thinking about ratites. We’ve written about them before, in our series about bird sex as well as the Cassowary poem.

There are four new Rhea chicks at the Smithsonian National Zoo in Washington, D.C. Here is a photo of the Dad and some of the chicks, taken by Mehgan Murphy of the National Zoo.

Rhea fathers raise Rhea chicks. The Rhea species depends on the father Rheas to do this, otherwise it would not survive: Rhea mothers are given to eating their offspring and it is the fathers who protect them. The dads also build nests, incubate the eggs, and take care of the babies for their first six months on the planet. Perhaps the polygamous males are feeling guilty about all the females they court each mating season. But they don’t need to feel guilty; as soon as the female lays her eggs, she is off after other males.

Native to South America, they are named after the Mother of the Gods, Rhea. Rhea, in Greek mythology, was the daughter of the sky (Uranus) and the earth (Gaia). She married Cronus and was the mother of Demeter, Hades, Metis, Hera, Hestia, Poseidon, and Zeus, in that order. Cronus, you will remember, had a guilty conscience. He had castrated his father Uranus and imprisoned him. (Yes, he was both husband and brother of Rhea but that is OK for gods. They don’t have to worry about chromosomes and inbreeding.) Anyway, Uranus and Gaia tell Cronus that one of his sons is going to do to him what he did to Uranus. But Cronus is resourceful, as Rhea gives birth to each of their children, he swallows them alive. (Perhaps that is where the male Rhea got his guilty conscience and leads him to protect his chicks.) Eventually, Rhea gets tired of going to all the trouble of bearing young, just to have her husband/brother eat them so she arranges to hide young Zeus and gives Cronus a rock wrapped in swaddling clothes to swallow rather than a young god. Zeus eventually grows up and the rest, as they say, is history. Cronus is given an emetic and regurgitates all the other children. There is a war, Cronus loses and accounts of his end vary. Most are not happy, although in one Zeus makes him the king of Elysium.

Why Paul Heinrich Gerhard Möhring, the German physician, botanist and zoologist who named Rheas, chose the name is unknown. Möhring wrote a book called Avium Genera, published in 1752. It was one of the earliest attempts to group and classify birds. Traces of his organizing efforts are still visible in modern groupings of birds. Which is remarkable, considering that he knew nothing at all about “Y” chromosomes.

Bird Sex, Part III

Dr. Olivia Judson, an evolutionary biologist who has a blog on the New York Times web site, recently asked one of the burning questions of modern science: Did Tyrannosaurus rex have a penis? Or two as some modern lizards do? Or, like most birds, none? (You can read her post here.) Modern birds may know the answer.

We know this question has been keeping you up nights and we’re happy to answer it.

Wait. Not so fast. First we need to set the stage. Five times in the known history of the planet mass extinctions wiped out most forms of life here. The biggest — the Permian-Triassic — happened about 251 million years ago, last Tuesday. (251 mya) The most well-known mass extinction was about 65 million years ago. (65 mya) This was the famous one, the Cretaceous Extinction, probably caused by an asteroid hitting the earth’s atmosphere somewhere above what is now the Gulf of Mexico. The resulting explosion vaporized everything nearby and sent up a cloud of dust so thick that it was decades before the sun shone through again. In the meantime almost all terrestrial life had starved or frozen to death, including the dinosaurs.

Not all life forms were wiped out. Obviously some survived; otherwise insufficient time would have passed for evolution to reach its pinnacle — the blogger.

A few bird ancestors lived through it. Specifically, two “superorders,” the Palaeognathae and the Neognathae. (There will be a test. ) Frankly, we know very little about how they came to exist before the extinction or how they survived it. About all we know for sure is that modern birds came from the two superorders, both of which came from dinosaurs. As Judson tells us, “Birds are more closely related to T. rex than they are to any living form.”

While we are fairly confident that birds evolved from dinosaurs we are not sure from which dinosaurs. One theory holds that birds evolved about 230 mya from Thecodonts. Another argues that birds developed from Theropods 150 mya. (Remember, there will be a test.) Still another asserts that birds arose from Dromaeosaurs about 110 mya. Which is correct depends on how dinosaurs learned to fly. Did they start by soaring or jumping or running after insects? More on that in a later post. Today we are concerned with sex, not flight.

As we discussed in our earlier posts about bird sex, which are here and here, most birds do not have penises. Procreation occurs when male and female birds touch their cloacae to one another. Only a few bird species possess penises. Some waterfowl and large flightless birds do. So do male crocodiles which, like birds, have cloacas; but also have a penis down which sperm passes on the outside, which is true for penis-owning birds as well. Crocodiles too descended from dinosaurs.

We’re close to the answer now. But first, we need to remind you that the fossil record does not answer the question about T-rex’s genitalia. The reason is simple: Except in a few mammals, penises consist of nothing but soft tissue which does not fossilize well. No fossil record of dinosaur penises exists. Which is why we look to birds for the answer.

Here is Dr. Judson’s answer:

The palaeos comprises the big flightless birds such as ostriches, emus, rheas, and cassowaries, as well as kiwis and an obscure (but flying) group of south American birds, the tinamous; the neos covers everything else. The palaeos have penises; like crocodiles, they keep them tucked into their cloacae. Again like crocodiles, the organ has an external groove for sperm. What’s more, the lineage leading to the other endowed birds, the ducks, geese, and swans, appears to have split off from that of the other neos relatively early.

This strongly suggests that the ancestor of all birds had a penis, and that at some point early in the evolution of the neognathous birds, the penis got lost.

Now you can get some sleep.

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Part I of this series.

Part II of this series

California Condors – Current Status

305. That is the number of wild California Condors known to exist as of October 1, 2007. 78 live in California and 63 in northern Arizona and southern Utah. A new chick fledged in the Grand Canyon this year. It was seen on October 24th and was seen to take a short flight above its nest cave which is just above the Redwall. Grand Canyon naturalists also saw it being fed by its mother. The fledgling is the sixth Arizona chick known to have fledged and the fourth confirmed with the Grand Canyon since the original release program began in 1996. Five of those are still alive.

Four more condors were released from the Vermilion Cliffs area of northern Arizona on October7th.

This photo of a fledgling is not this year’s Grand Canyon fledgling but, let’s face it, finding a good photo of a baby California Condor is almost as difficult as finding a real one. Click on the photo for an enlarged version.

Piping Plovers v. Feral Cats

By now you probably have heard about the criminal trial in Galveston, Texas in which the founder of the Galveston Ornithological Society was indicted and tried for shooting a stray cat that was about to kill a Piping Plover. The jury deadlocked yesterday with 8 members in favor of convicting and 4 against. The District Attorney must now decide whether to try the case again. [1]If convicted, the birder could get up to two years in prison. Texas now outlaws the killing of any cat; but, at the time of the shooting, it was only illegal to kill a cat that belonged to somebody else. The deceased lived under a bridge in Galveston and the maintenance man there fed and named the cat although he had not purchased it; it did not live with him and he did not have it vaccinated.

No one knows how many feral cats there are in the United States. Somewhere between 60 million and 100 million. We do know about how many Piping Plovers are left. About 6,000. In the entire world. They are on the Endangered Species Act. The plovers are native to North America, the cats aren’t. Cats are an exotic species in North America brought and kept here by humans. Plovers are ground nesters and defenseless; having evolved in a North America free of cats.

The case caused an eruption among animal activists who are against killing feral cats. Wait. Before you birders stop reading, we’re going to say a couple of nice things about those people. They make two serious arguments, one of which is undeniably correct. And they profess to have pretty much the same goals as birders: the humane elimination of outdoor cat populations.

For instance, Alley Cats Allies, “. . . is dedicated to advocating for nonlethal methods to reduce outdoor cat populations.” The folks at Feral Cat Network believe:

the safest place for domestic cats is indoors; cats who are lucky enough to have a home should be kept strictly indoors. However, because of the overpopulation crisis, there are not enough available homes. The next best thing for homeless feral domestic cats born outdoors is a managed colony where food, water, shelter, and medical care are consistently provided.

Their first argument is: “Trap-Neuter-Return (TNR), the only humane, effective method to reduce their [feral cats] population.” They believe that an adequately funded program to trap all feral cats, neuter them and return them to their homeless outdoors will end feral cat colonies.

Science disagrees. Such programs have been studied in at least two Florida counties and one California program invested $9.5 million in managed cat colonies. Scientific studies demonstrated that less than five percent of feral cats were trapped and neutered. In the meantime, all the rest were doing what cats do, breeding. Cats, especially in warmer climates, breed year around; producing six to eighteen kittens each. For TNR to work, we would have to grab 60 to 100 million cats and neuter them all on the same day.

But feral cat lovers also argue – correctly – that the biggest single cause of the precipitous decline in bird populations isn’t cats, it is humans destroying bird habitats. If you don’t believe them, just look at this range map. Plovers used to live all over North America.

The Alleycats put the best face on this argument:

Considering the vast scale of human destruction of bird habitat, arguing about “cats-versus-birds” trivializes the critical issues facing bird populations today. Cat lovers and bird lovers can agree: the real danger to birds is humans.

The problem for the cats with this argument is that it overlooks the salient fact that the cats are a part of the human destruction of habitat. If Western Europeans had not colonized North America there would be no cats here in the first place. Not only are the cats killing the birds – and cats kill even when they are not hungry and do not eat their kill – they also kill other prey species which makes it harder for the birds to get enough calories.

Humans created this problem; it is up to us to fix it. Just because cats don’t kill as many birds as humans is no reason not to stop what killing we can. Nor should we overlook the fact that feral cats live short, brutish lives. No one argues that the status quo should continue. The status quo is not humane.

We should also note that feral cat organizations believe with birders that cats are lovely INDOOR pets which should stay indoors. Much of the feral cat population problem can be laid at the doorstep of lazy cat owners who let their cats roam free, do not neuter them and – in some instances – simply abandon them and their kittens.

The question is what can we do? Obviously one shooter in Galveston can’t kill 60 million cats. Especially if he is in jail for killing just one of them.

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[1] We wonder: Of all the tourists who travel to Galveston each year and collectively spend millions and millions of dollars in the local economy, how many go to see the birds and how many go to see the feral cats? Perhaps Galveston’s District Attorney has decided not to continue a career in elective office? Why re-prosecute this case? Another hung jury is the most likely outcome. We doubt that local businesses are thrilled about his decision to prosecute this case amid national publicity and ridicule. It is not easy to irritate a birder but once you do, your tourism industry is in trouble.

Aplomado Falcons, Part I – Meeting a Raven

Aplomado Falcons are rare birds. So rare, in fact, that no one really knows how many exist. Their historic range extended from casual visits to Tierra del Fuego north to northern Mexico and southern Texas, New Mexico and Arizona. Fossils of their Pleistocene predecessors have been found in what is now called Ecuador and Peru. No one even knows how many lived the United States. We do know that by the early 1960s none were residents in the United States. A vicious combination of DDT and elimination of the native grasslands had eradicated them. Some survived in northern Mexico but very few.

A breeding program begun in 1977 has released about 500 Aplomados in Northern Mexico and southern Texas and southern New Mexico. The remaining natural grasslands of the Chihuahuan Desert are natural habitat for them. One of the many good things Ted Turner has done with his life is make available one of his New Mexico ranches for a release program. This ranch is just south of the Bosque del Apache Wildlife Refuge in central New Mexico and at least one of the falcons has made its way there. We saw it day before yesterday and here are photos. It is a juvenile and it was making the acquaintance of a raven. Given the intelligence of Ravens, we wondered if the Raven knew how rare Aplomados are and just wanted to look at one “up close and personal.” We’re sorry the birds are so small in the photo but they were a long way away and the adapter which fits the camera to our spotting scope was even further so this is the best we got. We’ll return again soon and try again, hopefully before this bird grows out of its juvenile coloring.

The Color of Eggs, Part III

As you can see from the photo, our Araucanas have begun laying their blue eggs. You may remember from our earlier post that most of our chickens did not begin laying until I explained fried chicken to them. That did not work on the Araucanas and it wasn’t until this week that I figured out why: Araucanas are from Peru and don’t speak English. I don’t speak Quecha but fortunately both the chickens and I could communicate in Spanish. Can you say “fried chicken” in Spanish?

Which brings us to Part III of our series on the color of bird eggs. As we mentioned at the end of our last post in the series, scientists are not inclined to give credit to female avian artistry and look for scientific explanations of why birds go to the trouble of coloring their eggs. They don’t accept our “art hypothesis.”

Their answer is adaptation. The theory goes like this: To survive, bird eggs must protect the small birds inside until they can peck their way out. If egg-eating predators have an easy time finding the eggs, it is much less likely that little birds will live to hatch and then reproduce the species. After all, skunks don’t care whether the egg they eat today means no eggs for their grandchildren. (Or we assume they don’t.)

Like lawyers adducing evidence at trial, the scientists bring forth first, Exhibit A: the Killdeer, which lays eggs in the open. Such eggs would be easy sightings for visual predators unless well camouflaged, as Killdeer eggs are. Coupled with the small similarly marked and colored rocks which Killdeer frequently use to line their nests, the entire apparatus is practically invisible which obviously aids in Killdeer survival. (Killdeer are experts at distraction displays which we discussed briefly in our post about Rikki-tikki-tavi. They are ground nesters.)

Exhibit B consists of white eggs laid by birds which nest in dark holes such as Petrels, Woodpeckers, Kingfishers. White eggs are easier to see in the dark. Exhibit C brings more white eggs, this time of species which leave nests frequently but cover the eggs with grasses or other plants in the vicinity before leaving which hides the eggs from flying eyes.

But there is a hole in this theory and it is the White Leghorn hen, that prolific egg layer we and E.B. White talked about in the first post on egg color. The one who would stop to lay an egg even if she was on the way to a fire. If the purpose of egg color is camouflage to conceal the eggs from predators, who is in more need of that than a domestic chicken whose every egg is stolen from her by two legged mammals? Why does she lay white eggs visible for miles?  I think the scientists have a little way to go to finish their explanation. Given what we are learning about bird brains and how evolved they really are, perhaps scientists should take another look at our art hypothesis.

But I can hear them now, “It isn’t just chickens and birds that hide their eggs when they leave their nests who lay white eggs. Exhibit D contains the eggs of Hawks and Owls and other birds which begin incubating their eggs as soon as the first one hatches. No need to camouflage those because the parent is sitting on them.”

We’ll let you know the verdict when it comes in.

Egg Color, Part II

In our last post we talked about the lovely brown eggs our chickens share with us and we raised the question of how and why birds go to the trouble of coloring their eggs. Today, we’ll provide some answers.

A bird egg begins its life in the ovary which deposits the ova, one at a time, into a funnel – called the infundibulum, today’s big word – which swallows it up and sends it down the oviduct, the tube which transports the egg to the outside world. Because the outside world is the egg’s ultimate destination, it is going to need a shell to protect the embryo and it gets it during its passage through the oviduct, a process that usually takes about 24 hours. (That’s a Bar-tailed Godwit egg.)

The shell comes late in the process. First the ovum is dumped into the funnel. The ovum, by the way, is the yolk and it is fertilized in the funnel, a/k/a the infundibulum. (Use a word three times and it’s yours.) As the yolk heads down and out, it passes through a region of the oviduct known as the magnum where the first layer of egg white (albumen) is added. After the magnum comes the isthmus where more layers of egg white are added and the shell begins to form. Before finally reaching the vagina, the cloaca and then the outside world, the egg passes through the last division of the oviduct: the shell gland. Here the last of the egg white is added and the shell forms. Not only is the shell formed here, it gets painted here. The egg spends most of its 24 hours prior to getting laid here, usually around 20 hours. That time varies among species and is dependent on the size of the egg for which a shell must be manufactured and painted.

We should not fall into the idea that the shell is something simple. It isn’t. Made of calcium, mostly, it has to be hard enough to protect the embryo until it is a little bird; ready to punch its way out of the egg; but porous enough that air can get in and out. All the materials, including water, that the embryo will need are in the egg, except for enough oxygen. Nor is the egg big enough to contain all the carbon dioxide the embryo will expel before it cracks the shell. And finally, the shell can’t be so hard that the baby bird can’t fight its way out when it is ready.

What the shell looks like when it enters the outside world depends on the speed and rotation of the egg’s passage through the shell gland. Fast movement leads to streaked eggs; slower movement to spotted eggs. The bird paints the egg in much the same way an artist might paint a canvas, beginning with the background or base color. Bernd Heinrich compared pigmenting an egg to innumerable still brushes painting while the canvas is in constant motion. Something like an ink jet printer, I suppose. The pigmentation is laid down by glands excreting the color as the egg spins down through the shell gland. The spots, streaks and darker colors come next. Because the egg heads down the oviduct with its fat end first, that end of the egg usually gets more color than the thin end.(That’s an egg of the Paradise Riflebird of Australia.)

Now, we’ve reached the thin end of this post. In the next post of this series, we’ll discuss the theories of why birds go to the trouble of coloring their eggs. It is not effort free; the pigments have to be produced, foods must be eaten to help produce the pigments and energy expended. We can assume there is some reason for all that effort, and while it is possible female birds are just artists at heart, most scientists are not willing to give them credit for artistry and look for other reasons.

One more time: infundibulum.