ZOO 138, Monday, March 3, 1997, 12:00 p.m.
Today I'm going to start talking about the classification andnatural history of birds. This is covered in your IllustratedNotes.
Now, if you look at the classification you'll see that you arelooking at a class of organisms that has 2 subclasses. SubclassArchaeornithes, which includes only a single order. Interestinglyenough in that single order right now there is a single family,a single genus and a single specie.
So here we have a single species of animals that is so differentfrom all the rest that it is placed in its own subclass, and that'sfairly unusual.
That is in the subclass Archaeornithes, which means ancientbirds. It's a fossil organism from the Jurassic. All the restof the birds are placed in a subclass Neornithes, which meansmodern birds.
And there are 3 superorders. One superorder Odontognathae. Whatdoes "odonto" mean? Teeth.
So now I have told you the general characteristics of birdsis they don't have teeth. Here is a superorder which has the wordtooth in it. So that's a tip off that we're dealing here witha group that's represented only by fossil organisms.
So those are the Odontognathae, that single order is just oneof a number of orders of fossil birds that I'm only asking youto learn that one order.
Then there are some animals placed in the superorder Palaeognathae.What does "gnathe" mean? Where else have you encounteredthat? Gnathostomata. And what does "gnathe" mean? Jaws.
It's a general term that applies to the jaws. In this case itrelates to the roof of the mouth, to the pallet. Birds do nothave a secondary pallet. So this is, like, a technical thing thatI won't be giving you the details on. But it relates to somethingto do with the mouth.
And there are a number of words, only 2 of which I'm askingyou to learn, that are placed in that superorder.
There are actually a couple of superorders, not just the inthe ones I have shown here, but I'm trying to think of way tomake it not too complicated.
Let's look at one critter, it's placed in the genus Archaeopteryx.So that's the genetic name. And the species is a Lithographica(spelling).
Lithographica refers to the fact that the fossils of this animalthat were first identified were found in lime stone quarries insouthern Germany where lime stone was being collected to use inproducing lithographs.
Now, a lithograph is a sort of an old-fashioned way of makinga print. In other words, before they invented laser printers andso forth.
And the artist could make a line drawing, like a pen and inkline drawing of something, and that could then be a put on tothis very, very smooth, very fine stone and drawn on basicallyas lines of wax. And then they would soak this piece of lime stonein acid. And the acid would etch away the stone that wasn't protectedon the surface by the wax.
And then they would remove the wax and printing plate, and putink on the press and a piece of paper on there, and then comeup with multiple copies of this pen and ink line drawing.
So the reason that all that interesting art history is relevantin biology is because this stone was such a fine grained stonethat it was being used by human beings to make lithographs. Itturns out that there are the impressions -- fossilized impressionsof the feathers that covered the body and wings and tail of thisanimal. Without the impressions of those feathers left in thelime stone or the sediment -- in other words, what happened whenthis bird got fossilized, the bird dies, it falls down into thebottom of a shallow slow moving freshwater stream that has thematerial that's going to form this lime stone deposit.
And the impressions of the feathers are pushed into this softmud behind the body of the animal, and it gets covered over millionsof years. The whole thing turns to stone, but the impressionis there. And because this lime stone was such a fine grain materialit retained the impression of these feathers.
Normally, you would not expect to find fossilized impressionsof a soft body part, a nonbony body part, even something as hardas a feather. The impression was of the feathers and they werevery detailed. And the impressions, people have subjected themto microscopic analysis and found that they have the same structureof the feathers of a modern bird, barbs and barbules and hamuli.
The whole entire detailed microscopic structure can be seenin the impressions of these animals that were deposited in thissediment that led to the production of lime stone.
Archaeopteryx lithographica is classified as a bird becauseit has feathers. If it didn't -- if there were not impressionsof the feathers associated with this fossil -- there is only ahalf a dozen of these fossils, then the skeleton alone would havebeen classified as a fairly uninteresting saurischian dinosaur.
A number of years ago a paleontologist was rummaging aroundin some drawers in some cabinets down in the basement of the BritishMuseum of Natural History and found a couple of fossils of Archaeopteryxwhich he recognized as being the fossils of Archaeopteryx becausehe knew the skeleton.
These happened to be animals that fell into a place where therewere no impressions of feathers associated with the skeletons.And so some paleontologist dug up that skeleton and looked atit. And there were no feathers, and they said that's from thisperiod, but it's not too terribly interesting of a saurischiandinosaur, because these fossils had been filed as saurischiandinosaurs in this Museum.
And when this guy was looking through them he said well that'sinteresting, that's not a saurischian Dinosaur, that's actuallyArchaeopteryx. That's only because he knew the skeleton becausehe studied the ones found, and they were associated with the feathers.
The very first discovery of the Archaeopteryx was just the impressionof a feather a lone and you'll see that is in the Life on EarthVideotape. They go to the famous quarry in Bavaria in southernGermany and found a fossil feather. And that led to a tremendousinterest in finding out if they could find the skeleton, whichthey did.
Archeaopteryx, this is the bottom line, it is an excellent exampleof an organism that is intermediate between 2 major classes. Itis intermediate between reptiles and birds.
It has features that are clearly reptilian features, and ithas other features that are clearly avian features. And knowingwhat modern birds look like, we can identify some avian featuresthat are missing that are not really reptilian, but they are missingavian features.
The reptilian features of the Archaeopteryx include the factthat they have teeth in their skull. They have a long bony tail.
Look at the artist's rendition here. You see a tail featherattached along a sequence of caudal vertebrate. There is no concentrationor reduction in the caudal vertebrate down to a pygostyle, whichis what you see in a modern bird.
And also what we see in this animal includes in addition tothe wing feathers which are there, you can see that it has 3 relativelywell-formed fingers that have claws on the end of those digits.So they have claws. And on those are on the end of a fairly normallooking reptilian fingers.
Those are reptilian features.
Avian features, which are not typical of any kind of reptileare feathers. That's the predominant one. That's the most importantone. But they also have a good avian furculum, a wish bone. Andthey also have a very avian scapula.
Now, I think you identified the scapula on one of the bird'sskeletons in lab. And, you know, that's just a simple little blade.It almost looks like a knife blade. The bone is a very thin longscapula. It's nothing like the complexity of the scapula thatyou looked at from the mammalian skeleton. It's not even as complicatedas a reptilian scapula.
Both of these features here, the furculum and scapula are associatedwith the change in the arrangement of the muscles of the bird.They have this foramen triosseum opening or connection betweenthe coracoid or furculum and scapula, which is a place where theligament that goes from the top of the wing to a muscle, that'slocated beneath the pectoralis muscle.
If you watch a normal vertibrate, like me, if I'm pretendingto fly, the muscle that the produces the down stroke is the pectoralismuscle which is attached below the arm. And the muscle that producesthe up stroke is attached to the back side.
But birds have evolved this very strange arrangement where themuscles responsible for the up stroke are located underneath thepectorals and along a tendon that goes up and goes through thisforamen triosseum.
They don't use the scapula as a point of attachment for themuscle of the up stroke. They actually have a pully-like arrangementthat is underneath the pectoralis muscles. It's the one that contracts.And by this pully arrangement, it pulls the muscle up.
Now, that muscle underneath the pectoralis is called the supercoracoideus muscle. And when you go to the market, you buy it,it's called chicken tenders, the muscle that they sell. If youhave ever boned a chicken breast, you'll notice on the inside,if you actually cut the breast muscle off the skeleton, thereis this little tiny muscle that's hard to keep on there and ithas a big tough tendon. That's the tendon that goes on the foramentriosseum, and it's hard to keep them on when they commerciallybone chicken breasts.
They take that out and sell that. That's the chicken tendersmuscle. And that's the reason that they have this furculum andreduced scapula, because they have already had that change inthe range of their flight muscles.
So those are the avian features missing.
Avian features, that is the things that we know are associatedwith being a bird that are not present in this skeleton includethe uncinate processes.
Those are the strange little things that sort of project dorsallyfrom the ribs. They have no carina. That's the keel on the sternum.Remember not all birds have that, but most do. And they also haveno synsacrum, that long series of ossified vertebrate.
There is a lot of speculation as to how much of a flier Archaeopteryxwas. In fact, there is even speculation as to whether this animallived in trees or not. And you'll see different articles fromdifferent paleontologists arguing that, in fact, this animal evolvedthese feathers and was actually a runner and maybe just ran andheld it's wings out and glided.
Other ideas is that they really were arboreal, climbing up intrees and jumping and gliding from one tree to the next. We haveseen examples in many different vertebrate classes of animalsthat have evolved that particular habit.
Remember the flying snake, flying frogs, the Draco, the lizardthat glides between trees. So that's another possible explanationof why this bird evolved to be the way it did.
And there is also quite a bit of debate as to whether or notArchaeopteryx is the line of descent that gave rise to modernbirds.
The next oldest fossil bird -- the next youngest fossil -- thereare no old -- there are some fossils of birds that have beenreported recently that may be older than that. But the next youngestfossil bird is in the subclass Neornithes It's shown on the nextpage here. The genetic name of this animal is Hesperonis. Andit's placed in the Order Hesperornithiformes in the SuperorderOdontognathae.
And this animal's fossils are only about ten million years youngerthan Archaeopteryx. Of course, ten million years by human standardsis a substantial length of time. But in an evolutionary sense,it's not a very long amount of time for there to have been asmany changes that have occurred if you were going to try to get,from an evolutionary sense, from Archaeopteryx to a Hesperonis,to a fully modern bird.
You have lost these other reptilian features. You have evolvedthe additional avian features. And ten million years is not avery long period of time in which to have those changes take place.
If the mechanism of evolution is Darwinian natural selection-- and, of course, up until 20 years ago, it was the common dogmaamong biologists, Darwinian natural selection, which is a verygradual change and an accumulation of minisclue differences overmany different generations. That mechanism of evolution was theonly one.
And what we see now is that it is very likely that big changesin the evolution of a whole new taxa, of whole new major groupsmay occur very quickly by another mechanism of evolution all together,which is called saltahorhial (spelling) evolution, also calledmacro evolution.
I really don't have time to go into the details of how macroevolution occurs. But the basic idea is that it is possible thatbig changes might happen very rapidly, so the people who believedthat natural selection or that evolution by natural selectionwas the only mechanism, they hard a time believing that you couldget from Archaeopteryx to Hesperonis to modern birds.
But it is also possible in an evolutionary sense that thereis another more ancient bird or maybe a whole bunch of them.
The hypothesis is that that is referring to a fossil calledproavis, a prototype bird. And then suggesting that evolutionmay have taken one line towards Archaeopteryx, and another linethat leads to Hesperonis. And from Hesperornis we get the allthe rest of the modern birds. But that's a controversy evolutionarytheorists and avian paleontologists are still working on.
And as I said, there are some reports now of some more ancientbirds than Archaeopteryx and this idea that it may not be onthe line of evolution is not all that far off. Archaeopteryx maybe macro evolution, the major mechanism, and that Archaeopteryxis not the ancestor of all the rest of the birds.
But let's take a look at the birds that we have here in theclassification.
Remember the 2 subclasses are Archaeonithes and Neornithes.And there is only one Order Archaeonithes, that's ArchaeopteryxLithographica. All the rest of the birds are in the Subclass NeornithesThere are several Superorders.
One of superorders I have given you is represented only by fossilanimals. And some of the members of this superorder have teeth.And that's why they are Odontognathae, but not all of them haveteeth. But there are several orders that are placed in this groupthat are all extinct which did not have teeth at all.
So these animals are known from the cretaceous and they arein the Illustrated Notes. This animal has little sort of dottedlines coming off its head and chest, and that's the artists wayof representing this was a bird that if you look at its toes there,you see it has really big funny lobes on its toes. It's a birdthat, not unlike some modern birds, that are adapted for swimmingin water.
You're all familiar with the idea that ducks can swim andthey have webs between their toes. But there are orders of modernbirds that can swim and they don't have webs between their toes,but they have big flat toes that produce the surface area necessaryfor swimming.
So that's the order Hesperornithiformes. And this "iformes"ending has been adopted as a standard ending for all of the ordinalnames. All of the names of avian orders have that same endingon them.
All the rest of the birds that I'm going to be telling you aboutare living and placed in a couple of superorders.
The first superorder that I'll talk about is the SuperorderPalaeognathae, remember this Palaeognathae means ancient palate.And it refers to some details of the structure of the palate thatwe're not going to worry about in here. You'll learn more aboutthat in ornithology class.
But there are several orders in this superorder that you aremore or less familiar with. This one you may not be particularlyfamiliar with is the Order Rheiformes (spelling). The common namesof these animals are Rheas. There are 2 species, and these areboth found in South America. They are ostrich-like birds, notas big, but they are related to ostriches.
They are too big to fly, but they have primary feathers thathave lost -- in an evolutionary sense, have lost the hamuli. Theyhave the same arrangement on the feathers and wings of a birdhas that can fly, same number of primary and secondary feathers,but they don't have hamuli feathers. They are very soft and fuzzy.They frequently are used as -- you can make feather dusters outof them.
Sometimes ostrich plumes were used as part of military hatsand so forth. And they have the same structure as a normal featherwith a rachis and barbules, but they don't have hamuli, so theyare soft.
Rheas are very interesting birds. They get to be 4 or 5 feettall as an adult. They have a social structure that's similarto what we'll see in ostriches. They have a harem, a single malefor four or five females that he mates with. And in the Rheas,the male is going to incubate all the eggs. So he mates with allthese females and they can lay about one egg every day or everyother day.
And the females will lay eggs. He makes a nest, and the femalesdeposit the eggs. He waits until they get somewhere in the neighborhoodof 20 eggs in the nest and then he starts to incubate them.
Now, these eggs are really beautiful eggs. They are like aboutthat big. They weigh around 7 or 8 grams. It's a good sizedegg. And one of the species of Rheas produces eggs that's justan exquisite lime green. And the other one is a really lovelylemon-yellow color.
He'll get maybe 18 or 20 eggs in a nest and then he starts toincubate the eggs. And he gets them up to the normal incubationtemperature, and the females will continue to come back and dropoff eggs for about a week.
And this is really an astounding thing that at the end of theincubation period, it's around 40 days, all of them hatch at thesame time even though some of these eggs have incubated for asmuch as a week less than all of their siblings. They all hatchat the same time. And experiments were conducted with ducks, whichexhibit this same phenomenon, which is called hatch synchronously.
So the phenomenon of all the eggs hatching at the same timeeven though they haven't been incubated for the same length oftime, that phenomenon is hatch synchronously. It occurs in quailand ducks. It occurs in precocial species primarily where theyhave very large clutches, that is lots of eggs.
And this hatch synchronously is studied both in quail and ducks.And when the chicks are getting ready to hatch, they make a littleclicking noise that the other chicks in the clutch can hear. Andso they sort of send out this signal that says, "Okay, let'sget out of here. Let's blow this joint." And they all hatchin a very, very short period of time.
And they all go running around and the parents have to thenstart babysitting them and protecting them from predators. Andhatch synchronously appears to have evolved in precocial speciesbecause if we look at the dilemma of that male, he was sittingthere on these eggs, and he's got 20 chicks all running aroundin 21 different directions, and he's got 2 eggs underneath himthat haven't hatched yet. He doesn't know if they are ever goingto hatch, they might be infertile. So he's got to say, "Well,sorry, guys, it's time to go, you're either up or out."
I mean, you get out now and join us or he's going to leave.When he leaves those eggs behind they are going to cool down toenvironmental temperatures and they are never going to hatch evenif they would have hatched in another six hours. Once they cooldown they will not have the strength. So there is a very strongselective advantage of leaving when everybody else leaves becauseif you don't leave when everybody leaves you are going to cooldown and die. That's why hatch synchronously has been evolved.It is because of the sounds that the chicks are producing. Thatmeans it's time to leave.
So they have very highly precocial young because they canget up and run around after they are born.
Another superorder is the Order Struthioniformes. This is onlya single species. This is the ostrich. This is the only avianorder that's still around that has only a single species and they'refound in Africa. They also are the largest of the all the livingspecies of birds. An adult male ostrich is a little over 6 feettall. They weigh close to 150 kilograms, that's about twice asmuch as I weigh. It's getting to be a smaller ratio as time progresses.
They weigh around 300 pounds. And they can be 380 pounds orover. They are cursorial. They are adapted for high-speed locomotion.They are so big that they -- no bird weighing as mush as the ostrichhas ever flown. It is probably physiologically impossible fora vertebrate animal to produce the metabolic power necessary forflight when it weighs as much as these animals do. And so theyhave abandoned flight in order to become bigger. And they runin order to get away from potential predators.
They do not have a carina on the sternum. In fact, there area whole series of members of this Superorder which have a commonname that you might encounter that you should remember. They'recalled Ratites.
Now, that's a term that is so common when you -- if you studyanything about birds, you need to remember it, but it doesn'thave an official taxonomic status. The Ratite itself comes fromthe Latin word for a rat. And it's a reference to the fact thatthe sternum of these animals does not have a carina. So it lookslike a cat instead of like a sternum of a chicken. It looks likethe hull of a sail boat, if you can sort of imagination that.
So the name for animals -- Ratite is a reference to the factthat they have no carina on their sternum. They are almost certainlydescended from a bird that could fly. As I said, they have primaryand secondary feathers and a number of other features you wouldonly expect to see in birds.
So their flightlessness is not a primative characteristic. Itis not a remanent left over from a stage in avian evolution beforeflight evolved as some people a long time ago interpreted it.This is a secondary feature. This is something that they evolvedcoming from an ancestor which had flight.
Their cursorial adaptation includes the same as those you haveseen in lab. Reduction in lateral digits. The horse stands onone toe. And cows and other relatives have only 2 toes.
Well, ostriches are the only group of birds that have only 2toes. Some birds have 3, some have 4. But this is the only groupthat has 2 toes, and one of those is substantially larger thanthe other. So it's closer to the condition that you see in horsesthan it is what you see in cows and antelopes.
They also live in grassland habitats where cursorial adaptationshave evolved. And they do not stick their head in the sand, justto get that clear. They frequently can be seen at some distancestanding on the ground, and there is sort of a little rise betweenyou and the bird, and it looks like it's got its head stuck inthe ground. But, in fact, they do not have their head in the ground.They would not be able escape danger. So sticking your head inthe ground is probably something that nobody does.
They have very precocial young.
When I was a graduate student at UCLA, we studied bird eggs.We also got some ostrich eggs and incubated them. And the littlebaby ostriches, boy, talk about stupid animals. We kept them ina great big cardboard box. You know how cardboard sometimes hasareas that are darker than other areas. There was a spot on theinside of this box, and the ostrich thought it was food becauseof this search pattern that said things to eat are smaller andcontrast with the background.
So this bird would literally spend hours just pecking at theside of the box. And it nerve got it. But it just knew it wassupposed to peck at any kind of spot it saw. It did not learnfrom its experience.
Now, there are other orders of birds that are also placed inthis, that I'm not telling you about. One reason I want to mentionthem is because the distribution is really interesting.
In Australia there are 2 types of birds that belong in thisSuperorder, which is a group called Emus, which are kind of ostrich-looking.You'll see them, they are kind of drab colored. And then thereare also Cassowaries, which are really colorful. They have a funnyhelmet thing on its head. They have also have red and blue coloringon their neck. And they are probably one of the most vicious animalsthat you would ever have the misfortune of meeting. They livein the bush, out back of Australia.
And if you are in the forest wondering through the bush andyou couple across one, you're lucky if you survive. They havea razor-sharp toe. And they have this way of kicking when theyencounter anybody, that's just likely to slash your abdomen openand leave your guts hanging out on the ground. They are reallymean critters.
And so these guys, there are several different specie of these.They are found in Australia, and then in New Zealand we find someother members of this group.
The Kiwi is the only living representative of this other group.And it's a really funny looking little animal. You'll see themin zoos, but they are nocturnal, and in some ways they are --in many ways they are sort of like little mammals. They are nocturnal,so you can see Kiwi exhibit usually a reversed photo period.
Birds known as that were not even fossilized. They're knownas kind of preserved dried out specimens, known as Moas. Therewas a whole bunch of species, a dozen or more, that were exterminatedin New Zealand. When the first human beings got to New Zealandthey killed them off. And some of them were bigger than ostriches.
But the interesting thing here is that you have them in Africa,South America, Australia and New Guinea, New Zealand, groups ofbirds that are all placed in different orders but are all fairlyclosely related to one another.
They all have similarities in their social biologies. They havesimilar kinds of breeding systems and yet they're all terrestrial.How do you get a get bird from Australia to New Zealand to SouthAmerica or Africa? And once again, the answer is the continentaldrift. These animals apparently evolved back when the southerncontinents were all fairly close to one another. At one time thesouthern continents were all a single continuous land mass thatgeologist called "Gondwanaland."
Have you ever seen somebody with a bumper sticker that said"Reunite Gondwanaland"? You know you're dealing withsomebody that is sort of geological --
Since all southern continents were once a single continent --look at the coast line of the east coast of South America andthe west coast of Africa, you can see those continents used tobe continuous. So these animals apparently evolved either at aboutthe time Gondwanaland was just still together or just about thetime it was starting to brake apart.
Or they are descended from some small turkey-sized bird thatcould fly and they have drifted to their present location on thesecontinents over the course of the last 65, 70 million years. Sothey are all similar to the terrestrial birds that are descendedfrom some birds that could fly.
STUDENT: When you said the Emus and Cassowaries are relatedto ostriches, that doesn't mean that they are part of this --
INSTRUCTOR: They are placed in separate orders. All these animalsare placed in separate orders. I'm not telling you the namesof these orders, but the point I'm trying to make to you is someappear in South America, Africa, Australia, and some appear inNew Guinea as well as New Zealand.
When I was working on doing that work on eggs, we thought wewere going to get some Cassowary eggs, because we heard therewas a guy in Phoenix who was breeding Cassowaries. He had onefemale Cassowary. And the only time of the year that she wouldlet the male Cassowary get anywhere near her was during the breedingscene. And he had this big fenced in yard with a 12 foot highchain-link fence that was the pen where he kept the female.
And we heard that she kept her nest close to the fence, andso he was able to reach in underneath the fence with a big scoopthing and get the eggs out and then he could raise the eggs inan incubator and sell the babies to the zoos which are tryingto get more animals.
And one year she got smart and she put her nest out in the middleof the field where he didn't dare go by himself. But he knew fromexperience that if he went in there with his lawnmower that wasgasoline powered -- he went in there with his lawnmower, she wasscared of the noise this thing made.
For a couple of years he was able to go out there and get theeggs out of nest in the middle of the field, until one timehis lawnmower died on him in the middle of the field. And he hadto run for his life just in order to get out there before shecame after him and sliced his guts open.
And then he had to go get his rototiller to go rescue his lawnmower,because she was also afraid of the noise made by the rototiller.
That's an animal you really don't want to encounter.
The rest of the birds are in the Superorder Neognathae. Andthis is the Order Sphenisciformes. These are the penguins. Andthere are 17 species of penguins, and they are all found in thesouthern hemisphere.
Now, the species of penguins actually nests on Antarctica. However,they have a much broader distribution than that. There are speciesthat nest on the southern tips of the major continents, on thetip of South America, on parts of Australia, and the southerntip of Africa. But they are also found in the Galapagos Islands,which is only one degree south of the equator in the Pacific Oceanoff the coast of Peru.
And the reason that they are there -- and, in fact, what isreally the common denominator of their distribution is the presenceof the very cold ocean waters. It turns out that cold ocean watersare actually more productive than warm ocean waters. Which insome ways is sort of counter intuitive. You might think warmthings, lots of things grow there.
But it turns out that when ocean currents are flowing out ofthe Arctic or Antarctic, its movement causes what's called upwedge (?) which is nutrients that have settled on the bottom ofthe ocean are raised up to the surface. And so cold ocean currentshave a richer supply of necessary nutrients. And so the food chainis much richer. There is a larger production of total micro organismsthat feed larger organisms and so forth.
So we find the greatest production of -- sort of a primary productionof plants and small microorganisms, small animals, in cold oceanwaters is where the penguins are found since they are exclusivelymarine, they live only in the ocean, they feed on several differenttypes of marine vertebrate, animals like small crustaceans andso forth and fish that are going to be found where there is thegreatest abundance of those food supplies.
And in cold oceans it turns out that even though the GalapagosIslands are located within one degree of the the equator, thereis a very cold ocean current that flows northward along the westcoast of South America by Chile and Peru. It comes out of theAntarctic Ocean and flows northward along the coast of Chile.It's called the Humbolt current.
And when it nears the equator it turns and heads towards thewest. And, in fact, the Humbolt current is the conveyer belt thatdelivered animals and plants from South America to the GalapagosIslands. And so there is a Galapagos penguin that's lives in thosecold ocean waters.
And now the other association you may have from common culturesis penguins being chased by polar bears. And penguins only livein the south poll, and polar bears only live in the north pole.That's not a realistic association. Penguins don't have to worryabout being chased by polar bears.
Penguins propel themselves by beating their wings up and down.They don't use their feet, which is another mechanism birds useto propel themselves through water. And they are completely coveredwith feathers. That wonderful little tuxedo outfit is composedreally of tiny little feathers that are maybe half a centimeterlong covering the animal's entire body. And, of course, they havea very thick layer of down feathers underneath that that providesfor insulation.
Now, and one of the things I'll be talking about as I discussthe classification and natural history of the birds is going tobe their beak specializations. I mentioned this on Monday in responseto one of your classmate's questions. And that is that bird'sbeaks are generally specialized for the acquisition of food, forcatching prey.
Whereas the teeth of mammals, which is the homologous structureare usually specialized for mastication among mammals. What wewould see is carnivores have sharp teeth for shearing up the meatthat they eat. Herbivores have large broad rough teeth that areused for grinding the food that they eat. Animals, like humanbeings, which are omnivores have a mixture of a grinding sectionand a slicing section.
And so the teeth of mammals are specialized for the kind offood that they are going to be chewing. But the beaks of bidsare specialized for acquiring the food. And that process of mechanicalbreakdown and increasing the surface area is sort of a functionthat is similar, sort of the same function of mastication. Thatprocess is performed by the bird's gizzard.
So when we look at a bird, many times we can tell somethingabout what kind of food they eat. Their beak is specialized forthe acquisition of prey. And what we see when we look at the manytypes of fish eating vertebrate animals is that they have a longrow of sort of simple homodonty teeth, little simple peg-liketeeth that help them hold onto the fish or squid or whatever theyare trying to eat.
And even those birds have beaks and therefore they don't haveteeth. What they have is a bunch of little simple conical projectionswhich, from a mechanical point of view, functions just like along row of homodonty dentition. So the beaks of the penguinshave this structure, a long little simple row of little conicalprojections that give them a nice tight grip on the slippery fishthat they are feeding on.
And that's if you stop to think about what the teeth of an ichthyosaurlooks like. It looks like that because they feed on fish. Theyhave the same kind of functionally, the same thing as we see indifferent kinds of fish they feed on, for example.
So those are the penguins.
And the next order is the order Galliformes. And these animalsare sort of generically referred to as the fowl. Although, thereare a whole series, something like 275 species. And many of thesespecies are quite familiar to you, including not only the turkeyshown here, but chickens and pheasants are members of this group.Guinea foul, which you will sometimes see running around parks.The pea foul of which the male bird is called the peacock, theguy with the great big fancy tail is a member of this group.
So there are quite a few members of this group that you arefamiliar with. They're all pretty heavy bodied with short wings,not very good at long distance flight. None of them are migratory.They all have the ability to fly short distance to escape predators,but not the kind that engages in long flight.
A couple of other interesting members of this group includean animal called a ptarmigan. Which is a little chicken lookingbird in terms of size, a little fat body guy. But these animalsare found in high altitudes, like the rockies. And they are alsofound up in the Arctic on the tundra where they are resident.
Now, stop to think about the challenge of being a resident ground-dwellingbird in the Arctic. That means that long Arctic winter nightswhen the sun doesn't even come up for days on end, you're sittingthere on the snow in extreme cold and maintaining your body temperatureso you don't freeze to death. And these guys feed on various --the ptarmigan feed on plant materials, loose buds, grasses andthings.
They can find one thing that that's associated with. And animalsof resident in these -- that is where there is a lot of dramaticground changes, being pure white in the wintertime to being brownin the summertime.
So their feathers molt, and these animals exhibit changesfrom being snow white in the wintertime to modelled brown forcamouflage in the summertime. And we're going to see that thereare some resident mammals like the Arctic fox that go throughthat same kind of color change as well. So there is sort of asimilarity that they turn white in winter to camouflage.
Another interesting member of this group are some Australiananimals called "mound-builders." Another name -- theseguys are also sometimes called "brush turkeys." Andthey are placed in a family which is an interesting one calledthe "megapodes." A translation of megapode is big foot.So these are not supposed to be large bipedal -- running aroundin Washington State.
But these guys, the 2 versions of the name that I showed youhere are related to the aspects of their biology. They build hugemounds of, like, rotting vegetation and sticks and sand and stufflike that. That's why they are called mound-builders.
And it's the type of chicken or turkey, and it scrapes up moundsof vegetation 12 feet high by 25 feet in diameter. And they dothat with their feet, which is why they have big feet becausethey scrape up these big mounds of vegetation.
Now, the reason they do that is they use the mound as an incubatorfor their eggs. Neither parent sits on the eggs, unlike whatwe see in almost all species of birds. The big mound of vegetationstarts to rot just like a compost pile. It is a bacterial breakdownand fermentation of organic egg pods -- it really is a heat mound-- and covers it up.
And then she's kind of a liberated woman because she flies awayfor a month and then she comes back a month later and lays anotheregg. And the little house husband mound-builder spends his wholeday, day after day -- for nine months of his life he's tendingto this mound and checks the temperature and sticks his beak downinto the mound to see if it's warm enough.
And if it's too warm he scrapes some off. And if it's not warmenough he piles more on. And unless the sun is shining and soforth. It's a very, very complicated formula that he is solvingon a daily basis. What he does need to do is keep the temperatureat their incubation temperature.
That's interesting that they do that, but the thing really amazingabout them is the young are the most precocious young in the tireclass Avies (spelling). Remember to stop and think about whatyou have seen sometime. You have undoubtedly hatched some duckeggs or chicken eggs. The little baby chick, it's all coveredwith down. And if you had a very ambitious 4th grade teacher,you kept the little baby around for some period of time.
And after a couple of weeks it grew contour feathers and flightand tail feathers and so forth. It molts the orange set of downin the process of growing out these new contour feathers and growsnew down feathers in underneath them.
Well, that is exactly the same process or same consequence thatthe mound-builders do. But they do it before they hatch. So themound-builders actually stay in their eggs so long that they gothrough their stage when they are covered with down and then theymolt the whole set of contour and flight feathers while they arestill in the egg.
And then when they are ready to fly, they hatch out of theiregg. They burrow through this meter of rotting vegetation. Theyget to top of this mound that's 12 feet high and they fly away.And they never see a parent. They don't even thank dad for monthsof incubating the eggs. They fly away. They nerve see a parent.They never associate with another member of their species untilit's time too breed.
There is an immense amount of instinctive behavior -- they areready to fly and when they hatch. And they go through this moltingwhile they are still in the egg. And that makes them the mostprecocious species of birds in the world. And there is a dozenor more of species of megapodes. And they are all in Australiaand New Guinea.
Most of the Galliformes are going to be feeding on various kindsof seeds, so the beak is specialized for feeding on seeds withhard coats. They have a conical-shaped bill. And there is a wholevariety of terms that are used for animals with different feedingspecializations. Animals that feed primarily on grain are called"granivores." So you can make up all kinds of namesthat different things, different organisms eat. And granivoresis the term we use for animal that eats grain.
Another very familiar order is the order Anseriformes. It isgenerally referred to as the water fowl. We have about a 150 speciesof these. And these have common names like swans, geese and ducks.And all the members of this order are -- virtually all with oneexception are immediately recognizable as being members of thisorder.
They have webbed feet. They usually spend part of their lifein water. And they are some of the most colorful and beautifulbirds that human beings keep in captivity. And they exhibit awide variety of different feeding specializations in terms oftheir ecology and the shape of their beak.
Some species of ducks are very highly migratory as you're alreadyfamiliar with. They go up to the Arctic to breed in the summertimeand then fly in huge flocks down into the temperate or tropicalregions. There is the old statement, you know, like "wateroff a duck's back." Well, the reason for that is the feathersare waterproof because they have very well developed oil gland.That's located right at the base of the tail.
And the bird reaches around and squeezes this oil gland andsqueezes this oil out of it and spreads the oil on the feathersso is the keeps the feathers waterproof and water rolls rightoff it.
And, of course, spending a lot of time in a cold place, particularlyin water, they need to have insulation. So they have a very, verygood layer of down feathers underneath their contour feathersthat keeps their skin dry and insulates them from the cold whether.That's not particularly unusual, but they have a very well developedform of it.
The very best down, which is best natural insulator, that youpay a high premium for if you go to buy a good parka or a goodsleeping bag, you are going to be getting what's called Eiderdown. It's a duck that nests on small islands off the coast ofNorway.
And there are Eider farmers, Norwegians who live on these islandsand they make their living by collecting Eider down and is sellingit. And interestingly enough, they do it as a renewable resource.They build houses on the islands. They are low, sort of wood houses.They pull seaweed out of the ocean and dry it and then put itinto the houses. So it forms a nice foundation for the nests forthe Eider ducks.
And the ducks come in the springtime and they go into the housesand they go into the big piles of nice soft dry seaweed that thefarmers have prepared for them, and when they are ready to laytheir eggs they make their nest and pull their down feathers outof their breasts and put it into the nest to serve as insulationfor the their eggs.
And it also produces a patch of bare skin on their bellies,which is called the brood patch and that will become very highlyvascularized and serve as the intimate contact with their eggs,so it keeps their eggs warm. And at the end of the season whenthe babies have fled and the parents have gone away, the Eiderfarmer goes out and he goes in and lifts up the house and he takesthe down that the bird voluntarily plucked out of its breast.He takes it and cleans it and sells to the rich Americans to putin their sleeping bags.
It's a nice renewable resource that is collected in an ecologicallyresponsible way. And it's the best insulation that you can getfrom a natural fiber. I guess there are some man-made fibers thatare beginning to be competitive in terms of their quality withEider down.
Now, beak specialization is associated with different breedingtimes that are fairly diverse. The common kind of duck is a dabblingduck. It's a filter feeder. They sort of go around in the waterand pump water through the edge of their bills. They pull waterup and pump it out of little projections along the edge of theirmouth and they filter out small plant and animal materials inthat way. So they are filter feeders.
Some sea ducks, including the Eider, feed on mollusks. Theyfeed on various shell fish. And they have a really stout powerfulbeak and for crushing their way through the shells of some kindsof shell fish to get the meat out of them.
Geese, they're the guys in sort of intermediate length, andthey feed -- a lot of time they feed on land. They are terrestrialherbivores. They may spend a lot of time in the water and havenests near water and so forth. They come out on land to feed onplant material, and frequently nest far inland in the tundra maybefar away from water, because they may be able to make a living feeding on plant material.
Swans are aquatic herbivores. So the reason that a swan hasa really long neck is not because it wants to look graceful, butbecause it wants to get to the aquatic vegetation on the bottomof the pond. So if you see a swan with its butt in the air, itsneck is down in the water looking for something to eat on thebottom of the pound.
Some swans, interestingly enough, are monogamous and form pairbonds that last for the lives of the bird. There is some amazingstudies that have been done in a place called Wild Feltress (spelling)where I was fortunate to spend a summer doing research where thereare people who can recognize swans -- individual swans. Thereis one woman there who can recognize about 2000 individual swansjust from the pattern of yellow and black on the face of the animal.
And what they know from studying these animals, because theylive for 20 or 25 years with the same pair, they will mate andthey will take off on migration in the springtime and they willcome back in the fall with a couple of babies called signets andspend the winter together and take off on migration again. Andthese animals are maintaining pair ponds for 15 or 20 years ifthey live that long.
Another interesting type of duck is a duck that feeds on fish.Some of the most beautiful of the ducks are members of the familythat are called "Mergansers." It's another example ofa bird that has this simple homodonty dentition. They have thesame kind of beak as the penguins do, a bunch of little conicalprojections. And they feed on fish and they named for an animalthat feeds on fishes, a "piscivores." You remember theastrological sign Piscies, well piscivores are animals that feedon fish. Piscivores, the sign of the fish and Mergansers havethat same kind of beak as the penguins do.
Another thing that is interesting, but you should just put itin your notes for future reference, is that they exhibit postgastric symbiotic digestion of cellulose. That's a mouth full.But it can be translated post gastric symbiotic digestion of cellulose,and I'll give an explanation for that later, but basically that'swhat horses do. They can feed on a high fiber diet and the fibergoes into their cecum where bacteria breaks it down into nutrientsthat the animal can absorb.
And so symbiotic means bacterial symbiotic digestion of cellulosethat's what the fiber is. And post gastric means that it happensin a chamber that's downstream from the stomach. So that's whata horse does, and I'll explain the biology of that more whenI talk about some mammals that exhibit the same kinds of things.
So geese exhibit that particular phenomenon. A very closelyrelated order is the order Phoenicopteriformes. And these animalsare the flamingos. There are only about 7 species of flamingos.They have a distribution where they are found in the tropicalregions of both the new world and the old world. So there is theCaribbean flamingos which is an almost all orange colored bird.
And then there are flamingos in Africa as well, and you mayhave seen some amazing natural history films of these in someof the great lakes in the African Rift Valley when the flamingosare together during the nesting season. There might be 100,000in a flock -- single flock of 100,000 flamingos, all on this onelake.
There is some amazing footage, you may have seen it. Somebodyflies by in an airplane and 100,000 birds all take off at onceand fly away, a stunning display. These animals are big long-leggedcritters with this funny bent beak as an adult. When they areborn they look like baby geese. In fact, they almost certainlyevolved from the geese. You cannot tell a baby flamingos froma baby geese. The baby flamingos beak is straight like a geese'sbeak, and it develops into a strangely bent structure as theanimal matures.
Of course, they come in a wide variety of really beautiful pinkcolors. Some are more intensely pink than others. And those pinkcolors, the animals can only produce those colors if they havea particular kind of colored molecule called a carotenoid in theirdiets. It is the same kind of general class of molecules thatcauses carrots to be orange. So you'll see the same root thereis carotene.
If you have a flamingos in captivity and provide it with foodthat has carotenoids in it, then its own cellular machinery willmodify that carotenoid structure and produce the pink moleculesthat then get deposited in the feathers when the feathers arebeing produced. And you have a pink flamingos.
If your flamingos does not have carotenoids in its diet whenit's molting, then you end up with a white flamingos. If you rememberto give it carotenoids, the next molting you can get a pink flamingosagain.
Here is an animal that has very bright color but it has to havethe proper molecules in its food to be able to produce that. Andone thing that's interesting about flamingos is that they also-- they exhibit what's called "social facilitation."They only breed if they are in large flocks, and that's calledsocial facilitation.
So here this word "facilitation" is similar to "facultative."It means assisted. We have seen that word in a variety of differentcontexts. These animals will only breed if they are in a largeflock. There is a good ecological explanation for that. It's interestingin itself, but here is the basic story.
You have a big bunch of flamingos, if you want them to breed,if you have only four or five in your flock, if you are a zookeeper, you'll never get any eggs laid. So you either have tohave a huge area with a whole bunch of flamingos or you have tohave a modest sized area and a mirror. And you see these in zoos,an enclosure that has a big long mirror along the side.
And that makes the flamingos think there is twice as many. Theydo this bizarre dance, which is a great big social group courtshipthing. They are not engaging in multiple partner sex, but theydo this group courtship dance where they all get out there andthey are all standing there and they walk around like this, andthey stop and they stick their head up in the air, and go klack,klack, klack, with their bill.
And they stick their head back down -- feather on the back,and they stand there up in the air and walk up in another direction.It's an amazing thing to see, 50 or 60 flamingos doing this thingin a big synchronized ballet.
And it's just a silly thing that they won't do it until thereare whole bunch of them doing it. But really it's not that. Reallywhat it is that in order for them to breed they need have to havea whole bunch of animals breeding at the same time. And we seethis same phenomenon of social facilitation without the funnydance in many different species of seaguls, for example.
And it generally seems to be explained that what these animalsare doing is they are trying to synchronize the whole breedingprocess. There has been evolutions of this behavior because whenall animals lay their eggs at the same time, then that limitsthe ability of some predator to specialize in feeding on eitherthe eggs or the new born young.
So you can imagine sort of a mental experiment, if you weresome kind of egg eater and you were living next to an Africanrift valley where there was 100,000 flamingos not breeding synchronously.There would be eggs around for months at a time that you couldfeed on. But when all 100,000 of them go through that bizarredance, and remember that that behavior is going to be processedby higher centers, and that behavior is part of this -- it takesto get the release of their gonadotropins and reach the properphysiological -- concentration of testosterone.
They all breed almost simultaneously within a day or 2. Theyall leg their eggs at the same time. They all incubate them. Theyhatch at about the same time. And here is this predator who wantsto make a living on eggs and baby flamingos, but suddenly thereis 100,000 baby flamingos along the edge of this lake. Well, youcan only eat so many a day.
And they do that because there is 100,000 baby flamingos atone time. Each baby has a lower probability of being eaten thanif the breeding season was spread out over a month. There arefewer babies around for a predator to pick off. The likelihoodof you getting eaten would increase.
So social facilitation is a synchronized breeding system andcontracts the period of time when the eggs and young are subjectto predation. And it is found in several different groups of birdswhere they breed in an unprotected location.
In other words, where the seaguls that nest in the sandy patchesnear the ocean where different kinds of predators can come inand feed on them or in these tropical areas are flamingos thatare breeding along the edges of these big pressure water lakeswhere there is all kinds of predators that can specialize in feedingon their babies as well.
Now, the beak specialization in the flamingos is this big bentthing. It has a bunch of little serrations along the edge. Theanimals have a big thick tongue which is somewhat unusual forbirds, and they pull water up into their mouth, close the beakand push the water out past the little serrations. And they filterout the plant, usually feeding on, like, red algae that's bloomingin the lakes at the time of the breeding.
But they're filter feeders basically.
So those are really interesting birds.
The next order that I'm going to talk about is another one thatyou're probably quite familiar with. This is the order Falconiformes.There are about 287 species.
Animals placed in this order, they go by names like eagles,hawks, falcons, ones that you're pretty familiar with, buzzardsand vultures.
So the California Condor and the great African Vultures areall members of this order. So basically what we see is the majorityof them that are diurnal carnivores. That is day-active animalsthat specialize in feeding on some kind of vertebrate food.
So, you know, you have falcons that specialize in feeding onbirds. Hawks that specialize in feeding on mammals and snakes.
You know, the Bald Eagle, the noble symbol of the country specializesin feeding on dead fish. And you also have vultures which arecarrion feeders. They feed on carcasses of animals that have died.These are nature's garbage men. That California Condor, one ofmajor problems with survival of the condor is the decrease inpopulations of dear which are the big animals that they wouldbe normally feeding on.
And one of things that caused the decrease in the populationof dear is that human beings don't allow fires to burn in theChaparral. And the Chaparral gets so thick that the dear can'tthrough, and the dear population is crashing, and the CaliforniaCondor is in trouble as a result of it. There are other thingsthat have contributed as well.
There are some small members of this order that are insectivores.And we have some of them on our campus. We have animals called"kites" which are really beautiful graceful white birdswith, like, a V-shaped tail. And many times if you look out inthe agricultural fields you'll see some bird sitting there flyingperfectly suspended in space.
And all of a sudden it swooops down on the ground. That's akite. Or it might also be another real small animal called asparrow hawk. Also, these animals are also called Kestrals, AmericaKestrals. Both are insectivores. They are the smallest ones. Youcan't be a very big bird and hover. Hovering is the most energeticphase of flight. Only small birds can hover. But both kites andsparrow hawks are able to hover.
They will feed on small -- kites are not insectivores; theyfeed on rodents. And the Kestrals will feed on small rodents.But they also feed on large insects as well, like grasshoppersand crickets.
We have quite a range of animals from the carnivores to thecarrion feeders to animals that feed on insects. But the majorityof the species in this group are day active carnivores.
There is a couple of really neat ones. There is a bird in Africacalled the secretary bird. And it's a big long-legged bird, ithas evolved two long legs. And they are specialized for feedingon snakes and stocking a snake. They hold their wings out in frontlike a shield, and stamp on the snake with this big long leg.They get ahold of the snake, they fly straight up in the air andthey let go. It's a little impact anesthesia on the snake.
There's a also a bird called the Osprey which a sea hawk asit's called, which is specialized in feeding on fish. And mostof these Falconiformes catch their prey with their feet. Theyhave very, very powerful feet. And they have a long needle-sharpclaws that they use for grabbing ahold of the prey. Those thingswill puncture the lungs and hearts and blood vessels and killthe animal fairly quickly. Very powerful. And those are calledtalons. Those are the sharp needle-like claws and powerful feetthey use to kill prey.
Now, most of the time, with the exception of insectivores, mostof the time the prey is bigger than the bird or, at least, asbig as the bird. They cannot swallow it whole. They cannot usea gizzard to perform the function of grinding their food. Theyhave a hooked beak, and they sink that into the body and theypull out a piece of meat that is big enough for them to swallow.
The generalization is that these birds use their beaks for theacquisition of prey. This is an exception. These animals use theirbeaks for functionally the equivalent of mastication.
Another similar but not terribly closely related order in termsof fossil records, these go all the way back to the end of thecretaceous is the order Strigiformes, and these are the owls whichthere are about 146 species. And they are generally nocturnalcarnivores.
Again, mostly feeding on birds or more frequently feeding onmammals that they catch, sometimes snakes, but mostly feedingon mammals. And they catch their prey again with their hind feet.They have talons, just Falconiformes. And they have hooked beaksthat they use for tearing the food apart.
Their feathers are a kind of very unusual velvety surface. Andthat's serves as kind of a sound proofing of the wings so youare much less likely to hear the wings of an owl beating thenyou would of the same size of a hawk. They make less noise becausethey are active at night and the prey are more likely to hearthem approaching than to see them. So they have evolved this soundproofing to make it harder for animals to hear them approaching.
Just as I told you that term "Ratite" as a generalterm that you'll hear it used for the ostriches and Rheas andEmus. Another term that I'd like you to know is the term Raptor.And Raptor, that is applied to both the owls and the Falconiformes.It's a reference to the these raptacious powerful talons thatthese animals have that they use for killing their prey.
The next of the last order is the order Apodiformes. And thereare 2 types of birds placed in this order that are not necessarilyparticularly closely related to one another, but they are bothlittle tiny guys. There are animals that are called swifts andthen there are the hummingbirds.
There are 80 species of swifts and 330 species of hummingbirds.The swifts are little aerial insectivores. They catch small insectswhile they are flying. And they have -- for the size of the headthese guys have they have a massive mouth. They can just openthis huge wide open gaping mouth, and they just fly around andwhen they catch an insect then they close their mouth and swallowthe animal.
Bird's nest soup is made from the nests of a little southeastAsian swift. All these swifts use a saliva to glue their neststogether. Swifts make their nests out of saliva exclusively, sobird's nests soup is really bird's spit soup, but it's got goodprotein in it. And you boil it up so it's nice and sterile. I'mtold it's quite tasty. I have never had the opportunity to tasteit, but there is no reason why it shouldn't be perfectly goodas any protein drink.
Of the 330 species of hummingbirds, they are all nectivores.And that means they feed to very great extent on nectar, whichis diluted sugar which flowers produce. They don't feed on nectarall the time because there isn't always nectar present. They sometimesfeed on small insects as well. They can't rear their young onnectar. My kids always thought they could survive on sugar andcandy, but you have to have amino acids to build proteins to makemuscles.
So they have to get some protein in their food when they arefeeding their young. But the parents do get a lot of their nutritionfrom this sugar water. The plants are producing the sugar waterbecause they have a symbiotic relationship that they have evolvedwith the birds. The birds serve as pollinators. So when the birdstick his long beak, specialization of a really long beak andan incredibly long tongue with a bottle brush arrangement on theend to soak up the nectar, when the bird sticks that in the flowerthey get pollen deposited on the forehead, and they go to anotherplant and stick their beak in there to get the nectar and transferthe pollen over the male parts of the flower of this other individual.
So the birds are serving as pollinators for the plants; andthe plants are serving as a nutrient source for the birds. Andthere is a whole area of the study of pollination in ecology.So the evolution of the relationships between the plants and thebirds, which is really quite fascinating and you will probablyhave a chance to hear about that in an ecology class sometime.
Hummingbirds are one of the few types of birds that exhibitwhat's called "torpor," where you have a homeothermthat intentionally gives up having a stable body temperature andit allows it's body testimony to cool down to ambient temperatureas a means of conserving energy. And the hummingbirds have evolvedthe ability to do that. At least, the ones that -- some of thespecies that are found in North America.
There are only like 7 species of hummingbirds in North America.The majority are found in Central and South America. They arenot found anywhere else, only in North and South and Central America.There are other orders of birds that have evolved this specializationfor feeding on nectar. But none of them are quite as amazing asthe hummingbirds and have the ability to hover which is how theygo about collecting the nectar.
The last order is Passeriformes. This order Passeriformes is sometimescalled the passerines, although technically that term only appliesto part of the order.
They are sometimes called the perching birds or the song birdsbecause they do have an extremely well developed structure calleda "syrinx" which allows the members to order quite abit more melodic sounds than do birds of other orders. Think aboutthe sound a duck or geese or parrot makes, it is not as melodicas a nightingale or a robin or sparrow.
And this is the largest order. There are 5,000 species roughlyout of the total of 8,200 that are found in the class avies. Sowell over half of the species of the birds are placed in thisorder. They have very altricial young, the ones that I have repeatedlyreferred to when I was trying to get you to see if you have anyconnection with this term altricial. Highly altricial. Finches,sparrows, mocking birds, robins, all those animals in your backyard at home, most of them are from this order.
Many of these birds are monogamous in their breeding. Thatseems to go along with altriciality of the young.
Some of the types, the other ones I have already mentioned thatare shown here on the page include the swallow which is anotherone which is an aerial insectivores. You'll see them flying aroundby streams and where there is water swooping back and forth frequentlyright around sunset when the insects are up. They also have verybig mouths that open way back on the side of their head. Big widemouth.
At the bottom of the page is a representative of probably thebiggest family within this order. And there are also sparrowsand finches. They're the 2 most common, greatest diversity interms of number of species in the families. And these guys areall granivores. And they have that stout conical beak necessaryfor breaking through the shell that covers seeds.
In a primitive sense they have evolved in the same time andassociation with the grasslands. When we look at the biomes, theplant communities around the world we have forests and tundra,rain forests, and the grassland communities are the most recentlyevolved communities. The grasslands are the most recently evolvedand the most highly evolved of the land plants.
And so in association with the evolution of the most highlyevolved land plants is grasslands. And in the grassland communitywe find the most recently and highly advanced birds. Members ofthe family are sparrows and finches. And you'll hear towards theend of the lecture next Wednesday, that's also the most recentlyevolved and most highly evolved of the mammals in some regards,and those are the antelopes and horses and their relatives.
The grassland community has brought along birds and mammals createdfor the evolution of these groups.
The bird in the middle is my favorite, it's called a "Shrike."And the shrikes, they are interesting because they are highlycarnivorous. They sort of look like a little mocking bird. You'llsee these guys in the chaparrals and deserts around here in SouthernCalifornia. But they will feed on insects, also on small rodents,they might catch a small mouse.
And these guys are not big animals to be doing that. They donot have talons, they are not like the Raptors, like owls andhawks in that sense. But they do have a little bit of a hook onthe end of their beak and they have to tear the bodies of theirprey apart in order to be able to swallow them.
In a sense, they are, at least, somewhat like the other bigcarnivorous birds. Another thing interesting is they have thisbizarre behavior, that when they have just eaten so much, theyare full and they catch a little mouse or they catch a big grasshopperor cricket, and they kill it, then they want to save it.
What they do is they will impale it on a cactus spine, or ifthey happen to be living near a piece of barbed wire fence, they'llhang it up on the barbs on the fence. It's not unusual to comeacross a mouse that is stuck on a barb or a cactus spine. Youthink that you are looking at some mischievous little 13 yearold boys playing around.
Actually, you just walked into the kitchen pantry of a Shrike.They will keep the animal there and eat it at a later time.
So those are the birds. And they are in many ways very similarto the mammals.