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Archive 1Archive 2Archive 3Archive 4Archive 5

Do you want to add a link to Bird Research News by ScienceDaily? I like it because the bird research articles are direct from research institutions around the world and updated every few days. There were some really interesting stories on bird migration, saving the Arabian Phoenix from extinction and aquatic origins of birds. But I thought it might be too much of a tangent from the article to discuss these findings right in the article. Any thoughts? See http://www.sciencedaily.com/news/plants_animals/birds/Michele123 14:46, 12 August 2006 (UTC)

Split into Bird anatomy

I suggest that a new article should be created to deal with this broad subject. There is already a bird skeleton article to deal with such a narrow subject, seems pointless to clutter the bird article with so much detail that will enevitably be added. I have ordered the current article to deal with the information as it stands, but it will not do for long. I say split; comments welcome - mastodon 21:00, 7 May 2006 (UTC)

Created bird anatomy under not much of a consensus, but I decided to be bold. Please feel free to check it out and edit mercilessly - jak (talk) 23:17, 15 June 2006 (UTC)

Controversy about bird origins

I notice that the entry reads that there is substantial evidence for the theropod hypothesis of bird origins, but while this is true, there are also continued and coherent criticisms of the theropod hypothesis by various ornithologists and/or paleontologists and it seems that the neutrality and comprehensiveness of the entry necessitates some mention of this. Or perhaps there should be a separate page to fully treat the issue of bird ancestry? --Calamus 17:14, 15 May 2006 (EDT)

The evolution section does include this: An alternate theory to the dinosaurian origin of birds, espoused by a few scientists (most notably Lary Martin and Alan Feduccia), states that birds (including maniraptoran "dinosaurs") evolved from early archosaurs like Longisquama, a theory which is contested by most other scientists in paleontology, and by experts in feather development and evolution such as R.O. Prum. See the Longisquama article for more on this alternative. If somebne wishes to expand it, preferably with citations to the various authors who reject the theropod origin, the Longisquama article may be a good starting point.Dinoguy2 21:18, 15 May 2006 (UTC)

My fault! Didn't read clearly enough I guess. I'll have a look. --Calamus 19:53, 15 May 2006 (EDT)

Mating systems and parental care

"The three mating systems that predominate among birds are polyandry, polygyny, and monogamy. Monogamy is seen in approximately 91% of all bird species. Polygyny constitutes 2% of all birds and polyandry is seen in less than 1%."

This is simply not true. Polygamy is far more rampant in the avian world than this. A distinction must be made between the tradtional concept of monogamy and social monogamy. JSB 142.150.48.172 21:01, 19 March 2006 (UTC)

Avian phallus

It is noted on the page that "The avian phallus differs from the mammalian penis in several ways, most importantly in that it is purely a copulatory organ and is not used for expelling urine."

Is this worth mentioning? Birds do not produce urine, so why would it matter that they don't expell it via their phallus? It is just as valid to say that they don't shoot balloons out of it, and equally absurd.

While some birds such as chickens have a very rudimentary phallus, in waterfowl and ratites (especially Ostrich) this organ can be large and well developed. You are correct in the discussion that it is intended as a copulatory organ. Birds do produce urine. In chickens it is estimated that an output of 500 - 1000ml per day could be expected. The ureters do exit to the cloaca where the urine will appear as a white cap to the feces. The urine is composed mostly of uric acid. Resource: Avian Physiology, P.D. Sturkie, ed. --Dr Bird 01:30, 19 April 2006 (UTC)

Also, is there some sort of reference that says they don't use this phallus for expelling waste? I am under the impression that the birds blessed with a phallus still only have one exit hole, the cloaca. Unless someone can find a source that says otherwise, I will remove this silly bit of information from the page. JSB 142.150.48.172 21:03, 19 March 2006 (UTC)

Noooo! The avian phallus (which can be quite some piece of work, see Argentine Blue-bill) works differently from the mammalian one: the cloaca does not exit through it, but it is a protrusion of the cloaca wall. The function of the avian phallus in copulation/fertilization is not quite resolved; certainly, most birds do well without one. Sperm does not run through the bird phallus, but along it. Dysmorodrepanis 15:47, 27 May 2006 (UTC)

Main photo

Shouldn't the first photo in the article (the one in the table) be of a bird showing its wings and preferably in flight? Image:Albaasmall.JPG seems like it would be a more representative photo. --mav 02:24, 30 Nov 2003 (UTC)

Ideally, yes. It (in a perfect world) would also be as representative a bird as possible - i.e., a passerine or (better yet) a near passerine, such as a parrot or kingfisher. Also it should be colourful (for visual appeal), and as crystal-clear as 250-odd pixels can make it. All in all, that adds up to a pretty tight set of criteria and I don't have anything in my collection to satisfy it. I doubt that Arpinstone does either. As I see it, the flycatcher is a temporary placeholder while someone finds (or takes) the perfect shot. Neither it nor the albatross is ideal. I'll not object if anyone wants to replace the flycatcher with the albatross, and I'll keep trying, though kingfishers are very thin on the ground in my part of the world. Tannin
BTW, over the next day or so, I plan to revise bird for layout: as it stands it has lots of good info but the layout is as ugly as a hat full of ... er whatnames.
Has anybody asked User:Jimfbleak if he has any pictures that meet the above criteria? RickK 02:52, 30 Nov 2003 (UTC)
They haven't, but I haven't. Jim


Wood pigeon

This is the best I can do but I don't think it's what you want. Pity about the strange object in the background, I suppose it's a water sprinkler. Let me know if you want me to put it in the taxobox. If it is wanted I'll have a go at removing the sprinkler in Photoshop.
Adrian Pingstone 10:41, 30 Nov 2003 (UTC)
I think your criteria are too narrow. We should find just a better picture than the current one, not an ideal. The current picture is also problematic, because it is non-free in Wikipedia-sense. I have no idea whether it qualifies as fair use, I am referring to the rules of Wikipedia Copyright FAQ.
I find all these images appropriate: Image:CommonMyna.JPG, Image:Female Chaffinch 800.jpg, Image:Common starling in london.jpg, Image:Southern grey shrike.jpg. Pick any that you like, my favourite is the myna. They are better than the Image:Lemon-breasted Flycatcher.jpg, because they are profile images and show the wing(s) and tail.
By the way, the mental image of a typical bird varies from place to place. I think that gulls and terns look far more typical than parrots. There are several images in Wikipedia showing them flying. But this must be a coastal, European bias... -Hapsiainen 01:22, Feb 6, 2005 (UTC)
I chose a starling photo instead of a myna photo, because it isn't so wide, and it has stronger contrasts. -Hapsiainen 00:57, Feb 11, 2005 (UTC)

no known poisonous bird species

My text about the interesting situation with no known birds being poisonous was deleted soon after I entered it. Why is it not a significant fact about birds, in general, that there is no known species that is poisonous to man? - Bevo 21:16, 5 May 2004 (UTC)

That isn't what you wrote though. You wrote that they are not known for being poisonous. The stronger statement you have made here on the talk page is more interesting. Morwen 21:20, May 5, 2004 (UTC)
I'll see what other comments appear here, and then maybe try a rewrite. - Bevo 21:29, 5 May 2004 (UTC)
I deleted it because there are very few species of any animals that are toxic when eaten, certainly no mammals, birds or reptiles. It would be more distinctive if they were toxic. If you meant venomous, same applies, vast majority are not venomous. The vague reference to an unnamed species is unhelpful, and the comment should be for that species when identified, rather than in a general article about all birds. jimfbleak 05:02, 6 May 2004 (UTC)
Thanks for the comments. - Bevo 15:44, 6 May 2004 (UTC)
IN any case, there ARE some poisonous birds - see pitohui seglea 01:54, 30 Jun 2004 (UTC)

"Birds in the genera Pitohui and Ifrita carry batrachotoxins, the same compounds found in some of the poison frogs of the Americas." [[1]]

A lot of birds are noxious or even poisonous when eaten. Bird-of-paradise soup was tried by explorers, but although these were rather tough guys used to eating all sort of weird stuff and in spite of being on a starvation diet, they found it tasted so incredibly foul that they threw it away (note that some female birds-of-paradies look fairly similar to the Rusty Pitohui, and it might be some form of mimicry). Kingfishers are also reported to taste bad (wasps apparently will not eat dead kingfishers). And so on. One of the early Dumbacher papers on pitohuis has a lot on this. I think it is notable that the majority of bird families are not - despite being generally available in numbers - hunted for food.
As a side note, not all edible birds taste like chicken. Far from it - grouse taste more like venison, ostrich is somewhat similar to extremely lean and somewhat tough beef, seabirds are rather fishy. Dysmorodrepanis 07:06, 8 November 2006 (UTC)

dolphins

whats with the dolphin picture???? Can i just remove it from birds article?--Zero00 14:50, 22 May 2004 (UTC)

What Dolphin picture? Morwen 14:55, May 22, 2004 (UTC)
I think Zero00 is referring to the neat photo of a penguin leaping from the water. I thought this was a dolphin at first too. Robertmacgrogan 00:58, 30 Jun 2004 (UTC)

Capital letters for common names of species - Please!!!

There is a huge discussion on the Wikiproject Tree of Life pages about whether we should use capital initial letters in the common names of species of plants and animals. However, it is (virtually) undisputed that we should always do so for birds, because that is the rule in the technical literature of ornithology. Please don't break that rule on this page of all pages, unless you can persuade everyone else that we should do away with it... and I don't fancy your chances. seglea 01:52, 30 Jun 2004 (UTC)

--- I agree that there should be a standard on Wikipedia, and capitals seem to be the easiest way to go. But it is incorrect to say that this is the rule in ornithological literature. Each journal has its own particular set of rules; there is no all-encompassing rule for this issue. JSB 142.150.48.172 21:04, 19 March 2006 (UTC) ---

Sorry about the capitalization thing. I was unaware that this had been the subject of much discussion since I did not see it mentioned on this page. And to me the capitalization seemed inconsistent, and I thought I was regularizing things. My mistake.Robertmacgrogan 16:44, 30 Jun 2004 (UTC)

Unknown species of bird

Could any of you bird enthusiasts help me identify some of the birds in these pictures? Thanks, – Quadell (talk) (help)[[]] 23:00, Nov 16, 2004 (UTC)

Ahem. This would be a classic example of the Ground Bird of the family ''birdidae''. By the way, does anyone know how to get to that and other gag articles? Tom S.

Mating systems and parental care

As a non-expert I can follow the start of this section reasonably well, but get confused and almost totally lost from these sentences onwards (end of second paragraph):

It is assumed that when such male care is necessary, monogamy will evolve directly with this. It seems strange then that a male’s ability to defend mates and resources relies on his ability to separate himself from parental care.

Ok, monogamy follows from male care. This reduces male's ability to defend mates (against competitors?) and resources (nesting sites?). Is the last sentence accepted by bird experts as true?

Further on there is this about male incubation:

With the extreme loss of mating opportunities, there is a reduction in the reproductive success among males.

Why would this lead to a reduction? I thought reproductive success meant success at producing an offspring, and not just success at fertlising an ovum, but what good does it do a species (or the male's genes, so to speak) if many ova are fertlised but very few (or none if incubation fails) develop to further pass on their genes?

The remaining paragraphs don't seem to state anything definite, but appear to be like an essay or an academic discussion, and we're left with the last unenlightening sentence:

For now, until more research is done, we must instead be content to just know it persists.

Sorry if this seems critical, but I honestly didn't get a sense of what the state of knowledge is in this area, but being a nonexpert cannot see how to improve the wording. -Wikibob | Talk 18:39, 2005 Jan 23 (UTC)


This section also needs editing for NPOV, and to discuss nonmonogamy as well. It's known that many apparently monogamous birds are not genetically monogamous; one recent study says as many as 40% of the eggs laid in their study species were fertilized by another male and not the mother's mate. ("Infidelity has its benefits", ScienceNOW 6 April 2005, original study in Proc. Roy. Soc. B) This section seems to be driving toward some particular theory of avian monogamy, and it seems odd that this isn't mentioned. -Bedawyn (7 April 2005)

This section was full of what seems to be POV academic speculation. Much of the speculation was not written very coherently, and I personally thought a lot of it was illogical. (Clearly if many bird species have monogomy and paternal care, it has been an advantage for them, so why all the statements on why it wouldn't be?) While my personal opinion as a nonexpert isn't that relevant, it gives me a strong suspicion that the material is either a misrepresentation of certain academic viewpoints, or the viewpoint of a particular group studying a problem which no one has reached a consensus on. At any rate, I don't think speculation on why monogomy and paternal care evolved among birds needs to be included in a general article on birds—I just want to know what their mating practices are today in an article like this. Hopefully someone who knows something on this topic can come along and rewrite what I left of the section to be more coherent and informative. —Tox 17:19, 26 November 2005 (UTC)

Bird bones

The article says birds have hollow bones. This is not true according to this link , my textbook, my professors. I'm going to edit that part out. -User:132.177.122.113 20:19, Apr 20, 2005

From your link: "Birds need to be light to aid flight, and their hollow bones reduce skeletal mass without sacrificing strength." You didn't understand the text. -Hapsiainen 21:13, Apr 20, 2005 (UTC)
Heres another one. I don't think that you understood it.
http://www.madsci.org/posts/archives/dec96/842732147.Zo.r.html
Their bones contain marrow and support structures.
Then you could write more about it under "Other anatomy". People were suspicious when you removed text. I don't think that word hollow is misleading. -Hapsiainen 11:21, Apr 21, 2005 (UTC)

You are both right. Using the chicken as the example "pneumatic" bones in the humerus are indeed hollow for flight and are less dense than the femur that holds the weight of the bird and has to endure the pounding of running. Just as there are specific muscle fiber types for these birds there are specialized bones depending on the area of the bird. Even the eye of a chicken has a bony ring in order to retain its connical shape. --Dr Bird 23:40, 24 February 2006 (UTC)

Classification of Bird

Is this classification for birds correct:

Scientific classification Kingdom: Animalia Phylum: Chordata Class: Archosauria Superorder: Dinosauria Order: Saurischia Suborder: Theropoda (unranked) Tetanurae (unranked) Coelurosauria (unranked) Maniraptora Class: Aves Linnaeus, 1758?

All those strange dinosauria, etc classifications seem to have been placed here by accident? DarthVader 07:55, 17 July 2005 (UTC)

In fact, the whole Dinosauria branch is fair enough. However, the class of Aves should be removed if putting the birds in this taxonomy is the intention. DarthVader 12:17, 17 July 2005 (UTC)

This is a ridiculous classification scheme. Cladism threatens to overwhelm us! I'm going to take out everthing between Archosauria and Aves, and instead inser Subphylum: Vertebrata. We are an encyclopedia, and we should be giving textbook taxonomy, not highly advanced cladist conceptions. john k 04:24, 26 August 2005 (UTC)

I understand the desire to use traditional taxonomy in the encyclopedia. However, I think a good definition of what a bird is should be provided, so that those of us working on the dinosaur sections know where to put those pesky dinosaurs with feathered wings and likely gliding ability. So, if any of you ornithology types can provide a strict definition of Class Aves, it would be appreciated. Dinoguy2 00:17, 1 December 2005 (UTC)

Why don't you put put those pesky dinosaurs with feathered wings and likely gliding ability under dinosaur? Surely there's a page expressly for Dinosaur vs. bird quibbles. --Wetman 10:20, 1 December 2005 (UTC)
So, in other words, despite the fact Wiki uses Linnean taxonomy, we should stick to cladistic definitions? Sounds good to me, but I just want to make sure both bird and dinosaur are on the same page here. So we can agree that Bird="the most recent common ancestor of Archaeopteryx and modern birds, plus all its descendents", not "feathered, winged, warm-blooded

oviparous vertebrates." Dinoguy2 14:33, 1 December 2005 (UTC)

This brings to mind the question of where dinosaurs end and birds begin. Or where any animal's lineage ends and another's begins.

That's why set, standard definitions are needed. As I stated above, right now on wikipedia a "bird" and therefore Class Aves is defined as a member of the clade Aves (The common ancestor of Archaeopteryx and Passer). Archie and everything closer to modern birds is Class aves, everything more primitive than Archie are Class Sauropsida, Superorder Dinosauria. Now, al ot ofthings more primitive than Archie look like birds, but because of this definition, they're not. Other things, like raptors, may be Class Aves or may not, they're too close to call at the moment.The Thagomizer 17:58, 27 January 2006 (UTC)
Not necessarily so. Clade Aves is usually defined as Passer domesticus, Archie, and their last common ancestor, and less commonly Passer domesticus, Struthio camelus, and their last common ancestor. Class Aves is the group where Passer domesticus (or some other modern bird or group of birds) belongs to and which has some shared synapomorphies. Archie is put into the class, but does not define it (Linnean taxa are not "defined" like phylo-taxa, but linked to an onomatophore and characterized by what is at that time is considered synampomorphies and and hopefully will forever remain so - feathers aren't so they have been struck from the Linnean characterization. The name is stuck to the onomatophore and if the latter is not invalidated as a taxon, it remains stuck there forever.) Both approaches come with their particular breed of inherent difficulties. See also below. Dysmorodrepanis 07:26, 8 November 2006 (UTC)
"Or where any animal's lineage ends and another's begins." - to make a koan out of it, precisely at the point where you cannot make out any distinction anymore and it seems like one continuum ;-) Dysmorodrepanis 07:26, 8 November 2006 (UTC)

Would you say that, perhaps, non-avian dinosaur is to bird as chimpanzee is to human? After all, tyrannosaurs appeared long after Archaeopteryx. (I'm not an expert on the dino timeline; would they have been among the very last before the big comet strike?) Also, the human family tree still isn't completely resolved, since people wonder if H. habilis, etc., were direct ancestors of H. sapiens or separate branches, and on the Archaeopteryx article the author states that "Archie" might not have been a direct ancestor of modern birds, but merely similar. Given these distinctions, I would say that Thagomizer is indeed correct in stating that "bird" should be a class in itself, not merely a branch off of "mainstream" dinosaurs.

The human-chimp example is an ok analogy, but not a parallel situation. Humans and chimps are distinct species in the same family, while birds and dinosaurs are extremely large groups. So, rather than say dnosaur is to bird as chimp is to human, it's more appropriate to say dinosaur is to bird as therapsid is to mammal. One group technically contains the other, but we divide them up for convinience. In this analogy, the problem becomes things like Castorocauda. It looks like a mammal, it has fur like a mammal, but technically, it just bearly misses that arbitrary dividing line we made between mammal and not-mammal. Dromaeosaurs and oviraptorids are the same way. By all rational accounts they are birds, but they don't make the cladistic cut. Some people use apomorphy-based definitions, however, where "mammal" means anything with the features a, b, and c (usually including fur). Under that definition, Castorocauda would be called a mammal. The original definition for Aves actually was apomorphy based (on feathers), and would include "dinosaurs" like Velociraptor.Dinoguy2 20:13, 19 April 2006 (UTC)
The link between birds and dinosaurs has not yet been proven, even though most paleontologists now agree that birds evoved from dinosaurs. However, it is not yet known that, if birds evoved from dinosaurs, whether they evolved from early "birds" (eg. Archaeopteryx and Sinopteryx), or if they evolved from dromaeosaurids (eg. Deinonychus and Velociraptor), or possibly other theropods (eg. basal Coelusauria, Ornithomimosauria, Oviraptosauria, Therizinosauroidae, and troodontidae). If the statement birds=dinosaurs is correct, then the taxotable would probably look something like this:

Birds
Temporal range: Late Jurassic - Recent
Superb Fairy-wren, Malurus cyaneus, juvenile
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Subphylum:
Vertebrata
Class:
Archosauria- Aves

Linnaeus, 1758
Superorder:
Dinosauria
Order:
Saurischia
Suborder:
Theropoda
Infraorder:
Coelurosauria
Family:
Dromaeosauridae-Other

Birds, see below
DO NOT ADD THIS TO THE ARTICLE(at least until the link between birds and dinosaurs is proven right or wrong)



However, until the link between birds and dinosaurs is proven right or wrong, the current taxotable should not be changed. AstroHurricane001 18:07, 1 December 2006 (UTC)

With all due respect, I think you're misunderstanding a few things about the relationship between phylogenetic taxonomy and the Linnean taxonomy used in the taxobox (no matter what birds evolved from, Class: Aves etc. can still be used in the taxobox, even though it renders its ancestor groups paraphyletic). Also, things in science can never be "proven" (as if Microraptor isn't proof enough anyway;)). That birds descended from theropod dinosaurs is supported by more evidence than any other hypothesis at the moment, and shouldn't be considered any more of a "mystery" than whether humans came from apes or some other, yet-unknown type of human-like mammal. Also, for the record, except for troodontids, nobody thinks birds came from any of those other groups you listed (unless basal Coelusauria includes Scansoriopterygidae as Czerkas thinks, but then all those other groups would fall under the term "bird", not vice-versa).Dinoguy2 03:53, 2 December 2006 (UTC)
No, because this mixes Linnean taxonomy and phylogenetic taxonomy. Classes are not clades, they are one particular level of clade which is fairly often paraphyletic.
Correctly, all Animalia would have to be placed in Opisthokonta for example. See that article on how to do a phylo-taxo-taxobox. As a rule, a most rigorous phylogenetic taxonomy (one that enforces monophyly über alles) is in essence anti-evolutionary, as it emphasizes only descendence and ignores fundamental bauplan changes and their significance a) in evolution and b) ecology. Dysmorodrepanis 03:50, 2 December 2006 (UTC)
Besides, Velociraptor coexisted with early modern birds such as Vegavis. Their lineages had long separated in the Cretaceous. How long, is the question; Late Triassic to Earliest Cretaceous, take your pick. That they were separated slmost 100% certainly at the time of Deinonychus is a good guess in any case; I think nobody takes the bird-dinosaur relationship that far. A crown taxon is never descended from a crown taxon of a sister clade. Dysmorodrepanis 03:58, 2 December 2006 (UTC)
Ok thanks for clarifying that up, and now I'll read the articles through the links you sent me. AstroHurricane001 00:00, 3 December 2006 (UTC)
Re "anti-evolutionary", b/c ppl certainly would take offense (and rightly so): A strictly phylogenetic taxonomy with completely enforced monophyly emphasizes descent (where something comes from) - but evolution is adaptation through natural selection (and chance, and...) of a lineage of descendants (where something that came from there-and-there is at, and why, and what happens next). See Moa-nalo, for example - descendants of the most ordinary of ducks, which became so utterly unlike any other waterfowl that ever (as of Dec 2 2006's knowledge) lived. The moa-nalo lineage, phylogenetically part of the Anas genus-level clade, was in fact ecologically and evolutionarily something no known bird has ever achieved. Their evolutionary pathways and those of the other Anas had parted for good, and for ever. But Meller's Duck is less closely related to the mallard phylogenetically than were the moa-nalos - and if you see a female mallard and a Meller's Duck side by side and cannot check the speculum feathers, they look all but alike except when you really know your ducks.
Put them in Anas or keep Chelynechen? Dysmorodrepanis 08:36, 3 December 2006 (UTC)
I agree, which is one of the big reasons why I advocate keeping "Linnean" type taxonomy along with using phylogentics to inform about ancestry. You have the same problem with any well-known subfamily of dinosaurs--tyrannosaurines, chasmosaurines, etc.--where there is a very clear line of descent in morphology and stratigraphy, and it's obvious that one species is the direct ancestor of another. Advocates of strict phylogenetics fail to recognize that "genus" and "species" are just as arbitrary as "order" and "family". Species aren't the basic unit of evolution, populations are, and they're impossible to keep track of, especially in fossils. Life is basically a continuum, and if you refuse to name paraphyletic groups, you are in principle refusing to name anything.Dinoguy2 15:04, 3 December 2006 (UTC)

Cleanup

For want of a more appropriate tag (please feel free to suggest one); I've marked this page as "Cleanup" because the "family tree" image lacks any, let alone meaningfil, alt text. Andy Mabbett 11:57, 23 November 2005 (UTC)

How about "Relationships between bird families". I think this meets the objective, as indicated in Wikipedia:Alternative text for images, of describing the function of the image. Alan Pascoe 21:48, 5 December 2005 (UTC)

Doubtful that sperm lasts a year

From the section on reproduction:

The sperm is stored in the female's sperm storage tubules for anywhere from a week to a year, depending on the species of bird.

It would be nice to have a reference for this, as I believe that most bird sperm will only be stored inside the female for up to a few months. - Spots 17:36, 11 March 2006 (UTC)

According to Avian Physiology, P.D. Sturkie (ed.) Avian semen maintains viability of at least 35 days in chickens. In Vitro storage of semen from chickens and turkeys has been difficult, due to the fact that finding the right diluents and storage temperature has proven problematic. --Dr Bird 01:46, 19 April 2006 (UTC)

Bird poop and good luck

Looking for the origin of why people say it is good luck when a bird poops on you.

This is a common reaction in many western cultures (US and Europe) and I can’t seem to find the topic on wikipedia.org.

I know this would probably not be listed under birds but I thought it would be a good place to start.

lmao, that's really hilarious. I guess it'll be a national holiday if it ever rained bird poo. "Ah, refreshing dung! Surely this must be a good omen!" ^_^

high-level taxonomy

The original entry claimed that Class Aves and its sister group, Family Crocodylidae, formed the Archosauria. This information would be incomplete without noting that the avians cannot be sister group to the Crocodylidae without also being sister group to the Alligatoridae. Thus, the more inclusive grouping, the Order Crocodilia, should properly be used here.

Vandalism

I'm bemused at how frequently this article is a target of vandalism. Does anybody have an explanation of why this should be? ACW 19:05, 5 May 2006 (UTC)

For on thing, as a general overview of a major group of animals, it may get increased traffic from school kids doing assignments. This demographic is probably more likely to commit vandalism.Dinoguy2 19:33, 5 May 2006 (UTC)
Interesting hypothesis. I'm going to go check Mammal, Reptile, and Fish. ACW 02:13, 7 May 2006 (UTC)

Bird Lungs

The article states that Fresh air moves into the anterior sac on inhaling, but various other sources say that fresh air only moves in to the anterior sac from the posterior via the lungs, and that the anterior sac only pushes stale air out through the trachea. Just wondered which is actually right? - Owz182

Have a look at this shockwave animation. www.sci.sdsu.edu/multimedia/birdlungs/ It is the clearest illustration of avian respiration that I have ever seen.

We can start from first principles to understand what is going on.

Air passes into the bird when its body cavity expands. Air leaves the bird when its body cavity contracts.

This body cavity includes the bird's chest and abdominal cavity.

There are air sacs inside this cavity: the posterior (or caudal) sacs, and the anterior (or crainial) sacs. The crainial sacs are nearer the head. The caudal sacs are further from the head.

The cavity expands all at once and contracts all at once. It does not rock on a pivot somewhere between the two sets of sacs. This means that both sets of sacs expand together and contract together.

Therefore it is not possible for the posterior sacs to supply air to the anterior sacs. The air expelled from the contracting posterior sacs can not be going into the contracting anterior sacs. The anterior sacs are contracting at this time, they are not expanding.

So where does the air go when both sets of sacs are contracting?

Ultimately the air is going from inside the bird to outside the bird.

In particular: air from the anterior sacs exits via the trachea, air from the posterior sacs passes through the lungs (from back to front) then exits via the trachea.

To complete the picture: where does air come from when the air sacs expand?

Air comes from outside the bird, down the trachea, down the mesobronchus from front to back, at this point half goes directly into the expanding posterior sacs, and half passes through the lungs (from back to front) and into the expanding anterior sacs.

Note: many sources wrongly state that air from the posterior sacs is stored in the lungs during exhalation so it can then be passed to the anterior sacs during the next inhalation.

This idea is nonsense!

The lungs are essentially fixed volume tubes with both ends open. We can easily do an experiment to see if a fixed volume tube can store air. Take a plastic straw (try your nearest fast food outlet), take a deep breath and blow into one end of the straw. Note what happens to the air.

At this point we can make an estimate of the amount of air stored in the straw, but we don't need to guess because its easy to test this. Block the other end of the straw (your finger will do) and breathe in via the straw. How much stored air did you manage to recover?

Did you manage to refill your lungs?

Of course you didn't.

The only way that bird lungs could store air passed into them would be for the other end to be closed and for the lungs to expand.

There are two problems:

1) There are no physical valves in a bird's respiratory system so the end is NOT closed.

2) We are told that the lungs are essentially fixed volume but even if they could expand there is still a problem. The lungs share the same body cavity as the air sacs. If the sacs are contracting then its because the body cavity is contracting. The lungs have nowhere for them to expand into.

Therefore it is impossible for the lungs to store air between respiratory cycles.

I labour the point because you will see the lung storage idea almost everywhere (websites and university textbooks). Its just wrong.

Why birds are toothless

According to Charles Weber, birds lost their teeth because of termites; "Since birds are usually a predator, the only way that I can conceive of completely losing so valuable an organ as a set of teeth from all non marine species, would be that they went through a period when the young were all insectivorous and were forced to eat termite flying reproductive alates at a time when a high proportion of the alates were humus eaters had soil in their gut.

Evolution toward lightness is not a plausible explanation by itself since gizzard stones are also heavy and teeth are very valuable and can be very small. Besides, teeth were retained for tens of millions of years prior to this and lightweight was canceled partly or wholly by stone ingestion. The iron and aluminum oxides of tropical soils form a phosphate that is highly insoluble in the slightly acid gut of birds." http://www.angelfire.com/nc/isoptera/soil.html

Don't forget the weight of the muscles needed to drive those teeth and the bones needed to anchor them and transmit their force. And don't get hung up on weight alone. Imagine the bird's body as a see saw with the pivot at the wings. The heavy gizzard is nearer the pivot and is below it. The bird's head is much further forward. Its beneficial to move the weight from the head to the gizzard.

And; "Ingestion by the reproductives of soil and humus eating termites (there are many humus eating species in the Amitermitinae) may have been the primary reason the birds lost teeth, however, with its phosphorus binding attribute in the bird's acid gut." http://www.angelfire.com/nc/isoptera/termites.html

Spurious to the max. Loss of teeth and development of some sort of beak or similar structure was something that happened for a variety of reasons in a whole bunch of theropods, just as several lineages of them evolved feathers. In early birds, the new possibilities for acquiring food simply made it a better deal to get rid of the teeth once and for all. The teeth of Hesperornis (and probably the entire Hesperornithes} are fairly peculiar; they may even have re-evolved them (which is not as hard as it seems) but sadly, no recent research deals with this question although Marsh himself assigned Hesperornis to a distinct lineage ("Odontolcae") because of the teeth (he had not yet found many remains at that time) Dysmorodrepanis 07:37, 8 November 2006 (UTC)

Bird anatomy and function

There are many puzzling features of the functioning of bird anatomy. In particular, my wife and I can not figure out how water birds' (such as geese or gulls) feet manage to function (or even remain undamaged) while standing on ice in subzero cold. We have also seen Great Blue Herons standing in freezing water. In the latter case, it is also a mystery what herons manage to find to eat when they overwinter in New England. Could somebody expand on Bird Anatomy so that these mysteries could be explained?

I think those details should go into specific articles about herons and ducks/geese/gulls, as they're unlikely to be general adaptations of birds. It is also possible to dedicate a special article to explaining such adaptations, and link this from the various dedicated articles (heron etc.). Regards, Samsara (talk • contribs) 18:18, 21 May 2006 (UTC)
You may want to look into concepts such as Supercooling. - Samsara (talk • contribs) 18:19, 21 May 2006 (UTC)
And possibly Antifreeze protein. - Samsara (talk • contribs) 18:22, 21 May 2006 (UTC)
Ducks, geese, gulls etc have an ingenious heat-exchange system IIRC in the upper leg area (the part that is hidden in the body plumage). It can keep their feet at just above freezing temperature (approx 4 centigrades I think) which is literally a cool thing. The main problem is not freezing their feet off - the tissue in these bird's feet is very thin, more or less skin 'n' bones, and rich in blood vessels which transport body heat to the feet -, it is actually freezing to death because they'd loose too much heat via the feet. So they let their feet cool down to just above the point where they'd get frostbitten. As necessiated by the conditions, a duck can regulate the temperature of its feet between c.4 and >40 centigrades, probably at will at least to some extent. Dysmorodrepanis 07:47, 8 November 2006 (UTC)

The 'see also' section of this article is really long, perhaps there is a case for a navigational template at the bottom of this article for articles about bird biology that are not related to the taxoboxes. Here is a very rough example, made without any skill, by canibalising the solar system nav box.

edit Birds
Anatomy: Bird anatomy - Bird skeleton - Bird flight - Avian pallium - Egg - Feather - Wing (bird) - Physiology (bird)
Evolution and extinction. Bird evolution - Archaeopteryx - Bird hybrid - Late Quaternary prehistoric birds - Fossil birds - Sibley-Ahlquist taxonomy
Ecology: Bird ecology - Bird populations
Behaviour: Bird song - Bird intelligence - Bird migration - Bird reproduction
Bird types: Seabirds - Shorebirds - Waterbirds - Song birds - Birds of Prey - Poultry
Birds and Humans: Extinct birds - Bird ringing - Ornithology - Birdwatching - Birdfeeding - Bird conservation

Of course it needs a lot of work, (we have lots of other smaller specialised articles that might make it in), but it would provide some redlinks that would prompt some needed articles on bird biology other than species articles, and it might tidy up the bottom of this article. Any thoughts, or major objections to this? Anyone with more programming talent than me? Sabine's Sunbird talk 07:28, 2 July 2006 (UTC)

Not bad :) you have my approval. Although the bird picture has a white square around it. I added some stuff, hope thats fine - Jak (talk) 19:22, 2 July 2006 (UTC)

aren't they Sauropsids?

Didn't the whole class of "aves" get thrown out a while ago? and yet, for example, chicken is still listed as aves. I'm confused. Citizen Premier 04:25, 19 July 2006 (UTC)

Usually, Sauropsida is used in the cladistic system, which does not use ranks. In these cases, birds are both sauropsids and avians. In the traditional taxonomic system, class sauropsida = class reptilia and does not contain class aves (meaning it is paraphyletic). Class Aves is still used by the vast majority of published sources.Dinoguy2 05:45, 19 July 2006 (UTC)

Modern college biology textbooks acknowledge the inclusion of Aves in Reptilia. Aves is a subclass rank. I find it disingenuous to continue using Aves at class status when that is clearly a misrepresentation. The controversy rests in finding a more accurate common ancestor for birds. The divergence occurred approximately 175 million years ago (mya) with the oldest known avian-like fossil being from 150mya, Archeaopteryx. Purves et al. (Life: Science of Biology, 2004) and later texts all make this acknowledgment.

To do list

This article is currently a top priority for the Bird Wikiproject and is listed as a good article. It clearly needs some work, however, if it is to reach FA status. A read through has given me this list of 'to do's; I'd appreciate thoughts, objections and suggestions of other things needed. I'm prepared to do a lot of this myself, but it's pretty major stuff so I'm fishing for feedback fisrt.

There is no information on bird behaviour other than nesting. Sections needed for bird feeding, migration, predator avoidance etc, combined with breeding section under behaviour banner.
Ecology section needed.
Changing nesting to breeding.
Evolution section needs to be split into own article, then a condensed summary placed here per MOS Wikipedia:Summary style. Bird evolution is currently a redirect to Paleornithology, so it can simply be un-redirected.
Expand the bird anatomy section to be better summary of separate article per MOS.
Inline cites. It's going to need a lot of them.
Birds and humans + Threats to birds needs to be one section (called relationship with humans) with three subsections - aviculture and domestication (+hunting) - role in culture - threats and conservation.
Images need to be rationalised. At the moment there are lots of pretty pictures that don't kink to the text. We have enough images on wikipedia and commons to chose good images that illustrate points made in the text, rather than just prettifying the article.
Get rid of trivia section, all the points there should be incorporated into expanded article.
Get rid of see also. Using a navbox and expanding the article should provide homes for most of the links, otherwise simply getting rid of them. Laundry lists are not FAish.

Anything I miss? Sabine's Sunbird talk 01:24, 21 August 2006 (UTC)

It may be useful to have a look over frog. It is the only featured article of a high taxon, and you can see what to do about some sections (like trivia, or popular culture in frog). It may also have some things you have missed out. I would like to go through the article, but I have to go to uni. --liquidGhoul 01:30, 21 August 2006 (UTC)

Protoavis as a coelurosaurian

Do you think that Protoavis was a basal coelurosaur?

No, but most paleontologists think its made up from parts of prolacertiformes, pterosaurs, and coelophysids. (see the EvoWiki article on it here [2]) Dinoguy2 21:56, 15 October 2006 (UTC)

Does this make sense to anyone?

" The three mating systems that predominate among birds are polyandry, polygyny, and monogamy. Monogamy is seen in approximately 91% of all bird species. Polygyny constitutes 2% of all birds and polyandry is seen in less than 1%. "

Shouldn't the sum of the percentages be closer to 100%? Joelito (talk) 19:35, 15 October 2006 (UTC)

Aves, "bird", and Archaeopteryx

User:Dysmorodrepanis recently added to the section High Level Taxonomy:

Fossils of advanced theropods recovered in the last decades have revealed that inclusion of Archaeopteryx in the Aves is quite problematical, as its relationship to modern birds is still unresolved and likely to remain so for the foreseeable future; as it was in all probability not a direct ancestor, including it in the Aves is fairly likely to include some more traditional dinosaurs within the Aves. Given the plethora or more or less birdlike theropods found to date, it is very doubtful that Archaeopteryx would be uncontroversially accepted as a "bird" in the traditional sense if it were only discovered today; it appears that several lineages of theropod dinosaurs evolved any number of bird-like characters like feathers of flight independently, and Archaeopteryx cannot even assigned to one of these with any reasonable certainty (see also Dinosaur-bird connection).

I removed this section because it does not appear to reflect common usage of the term Aves, or common usage of the word "bird". In almost all scientific literature, Aves includes Archaeopteryx by definition (Aves sensu Gauthier has been widely replaced by the term Neornithes), so the inculsion of Archie in Aves cannot be "problematical" (on the contrary, it's the exclusion of dromaeosauridae from Aves that's problematical). A "bird" in the "traditional sense", meanwhile, is "any of a class (Aves) of warm-blooded vertebrates distinguished by having the body more or less completely covered with feathers and the forelimbs modified as wings" (according to Webster's). Therefore, not only would Archie be considered a bird in the "traditional sense", so should all of Maniraptora (or at least the clade Microraptor + Archaeopteryx + Passer, if "wing" is taken to imply use or former use in flight).Dinoguy2 22:58, 7 November 2006 (UTC)

This is entirely correct of course, but I wanted to add the Thermopolis Archie paper which suggests that Aves as traditionally defined is either paraphyletic or includes "non-birds". Personally, I consider the "avianness" of Archie, Confuciusornis, Rahonavis etc to be fairly overstated in a phylogenetical context (because we're so much used to seeing birds and dinosaurs a la the obsolete, form-taxon concept) and predict the entire issue to blow up right in the face of the folks working on PhyloCode in particular and any ornithologist in general some time in the next, say, 10 years, so as not to give the creationists a field day when that happens, the issue could well be annotated. In any case, I think paleontology has advanced to a point where it is foreseeable that the conventional definition of Aves is gonna cause much trouble fairly soon. Linnean taxonomy can stand unfazed BTW as Linné did not know Archie and his "Aves" included modern birds only, naturally; the definition of the Linnean class can be changed (and has been changed and changed back) as seen fit; there are no rules whatsoever above family level except common sense.
That Webster's definition would quite likely include Microraptor in the Aves is a warning sign; flight in this critter and Archie was very different from modern birds, except that feathers played a crucial role in it... in any case, I think Gauthier's argument displays remarkable foresight, as either way, the odds are fairly large that including Archie in the Aves will ultimately lead to them including non-birds (the argument to do away with Gauthier's Aves was that Archie should be maintained in them to put all "bird-like" critters in one clade, but what if it is a very distinct relative? Then, the clade would contain a smattering of un-bird-like forms). Dysmorodrepanis 05:58, 8 November 2006 (UTC)
Unless modern birds and Archaeopteryx evolved from completely different ancestors (modern birds from say a drepanosaur or early ornithodiran and Archie from deinonychosaurs), there's little chance of un-birdlike forms being included. Most paleontologists today consider the "un-birdlike" dinosaurs you imply to actually be very, very birdlike (see the flap about John conway's Deinonychus drawing). I could see a problem if Aves were to include sauropods or allosaurs, but not oviraptorids.Dinoguy2 11:16, 9 November 2006 (UTC)
OK, what I meant with "un-bird-like" was characters such as primary flightlessness. As it is, the entire train of thought has little meaning for the page anyway and I'll just leave it at that. Suffice to say that Mayr et al (2005) hints at the possibility that the traditional Aves are paraphyletic, or include so many taxa not traditionally considered Aves (and never ever "birds" in the vernacular sense) as to render an autapomorphy-based definition (the only phylogenetic definition of a taxon I consider warranted at face value, because both stem-based and especially node-based ones define taxa via unknown entities, which is hardly science - but I'll gladly leave that to Sereno et al to find out the hard way ;-) ) futile. Basically, Aves fide Gauthier rests on somewhat solid evidence, whereas Aves fide Sereno is only justified by inference (due to lack of a solid Jurassic fossil record) - one could go as far as to say that it once again shows how cladisic methodology and phenetic reasoning are not exclusive.
Though I certainly would prefer Gauthier's definition because it stresses the uncertainties about what exactly happened between the Kimmeridgian and the Barremian as long as the evidence remains so scant, I see no problem with using either - especially as Aves fide Sereno is ATM the preferred definition among the phylo-taxo folks - as long as they are defined and referenced.
Re "un-bird-like" - Yes, I see it is a bad term to use. My point rests precisely on what you say: that so many assumed avian autapomorphies are now known to be either synapomorphies or ony autapomorphies in a much more rigidly defines sense that traditionally. There is simply too much "bird-likeness" in the Maniraptora for me to find a clear verdict is warranted or even possible at this time; Gauthier's Aves neatly circumvents this problem. But I have no intent to dwell upon this any longer; as it now stands, it is rather fine with me. Dysmorodrepanis 00:03, 10 November 2006 (UTC)
I realize I'm in a minority on this, (and it partly has to do with the fact that I'd bet lunch on the fact that maniraptora are secondarily flightless), but I prefer to circumvent the problem by using an apomorphy-based definition of Aves. As Senter (2005) points out, the earliest definition of Aves is even apomorphy-based (on feathers), in Charig 1985. I'd prefer something specific like "pennaceous feathers with a rachis and vane as in Passer domesticus". Incidentally, this is the description at the very top of the present article. It states "Birds are bipedal, warm-blooded, oviparous vertebrate animals characterized primarily by feathers, forelimbs modified as wings, and (in most) hollow bones." This describes all members of Maniraptora at most, or all members of Microraptor + Archaeopteryx at least, depending on your definition of "wing" (and depending on your preferred phylogeny, even that may include all or most members of Maniraptora).Dinoguy2 21:46, 11 November 2006 (UTC)

Systematics and evolution

I think the present lineup is satisfying to the degree it can be satisfying at all (it is frankly astounding to see that the Clements taxonomy is overall rather sound, given what it had to suffer). But there is need by now for some page to discuss the neornithine radiation in detail, i.e. to sum up the advances of knowledge since Sibley/Ahlquist (I frankly shudder every time I come across that wretched phrase "Sibley-Ahlquist propose a radically different...based on DNA studies..." in genus-level articles for which a) S/A does not apply at all and b) "DNA study", as if DNA-DNA hybridization was the same thing as, say, RAG-1 sequence comparison). I am not really a fan of S/A for that matter - their one major "breakthrough" was the pan-Ciconiiformes and they were apparently as wrong as one could be in that; basically everything else had already been proposed. The Galloanseres and Coronaves/Metaves studies which I have finally managed to dig up as well as the 2004 "hard polytomy" paper and the recent "refutation of the standard molecular clock"/the earlier Auk paper about "mixed support for the 2% rule" all deserve discussion, as well as the wretched Cracraft study of Hesperornis, to illustrate the pitfalls (IMHO what does not work in science is generally insufficiently discussed, to the detriment of science itself. Some non-avian-phylogenetics folks will still be using unrelaxed molecular clocks in 5 years' time, and publish the results they get with these, I fear...).

And what I'd be willing to say at present is that although there are some interesting groupings which far more often than not stick together in the face of different datasets, and passeriform phylogeny should be all but resolved by the end of next year, the interrelationship of the modern bird orders is still unresolved (Phaetontiformes, anyone? Why not; it is fairly reasonable). So there is some need to present something more substantial than "DNA studies" (the "hard polytomy" paper points out that it is of crucial importance which DNA sequence one compares and that simply adding sequences will fairly quickly make your CPU blow up rather than delivering a phylogeny than can be termed "robust" by any means; at least under the current cladistics SOP).

Any ideas how to call such an article? Classification of birds or Bird classification schemes maybe (Bird classification redirs to List of birds at present). The latter as well as Sibley-Ahlquist taxonomy would of course link there (and I am all in favor of "being bold" for List of Birds; I have done some resorting and incorporated new data already), and the introductory blurb of the S/A page would make for a nice treatment for such an article (S/A page itself is in need of reorganization, the TOC blows).

Basically, I imagine a page where a) major classification schemes such as S/A vs Clements, or Paleognathae/Galloanseres/Metaves/Coronaves are summarized, and b) proposals for groups of orders (like Mirandornithes or however Mayr calls his flamingo-grebe clade) are discussed. If this could be assembled and referenced, WP would have something that is really unprecedented and it would do well to improve its scientific merit. Dysmorodrepanis 09:02, 8 November 2006 (UTC)

No takers? OK; I think if nobody objects, I'll start off sometime soo, prolly in my sandbox at first. I think the whole thing should go under Bird classification (exchanging the redirect for a link in the article) with the other two which are more unwieldy redirecting.
As a side note and word of warning, having read and re-read Fain & Houde's Metaves-Coronaves paper, I find that the major Coronaves lineages seem to be good, but I wouldn't rule out parallel evolution on the molecular level for Metaves. The internal grouping in Coronaves is very consistent with the emerging picture (it even includes, lo and behold, much of the S/A's "Ciconiiformes" as a clade, and also the near passerines and Charadriiformes are at least damn close to being for real), but the internal taxonomy of Metaves is a total jumble (Tropicbirds-swifts-hummingbirds vs nighthawk-flamingo clade, sheesh! Never. Ever.) reeking too strongly of molecular convergence to build upon it. Gotta dig deeper still into the exact genetics involved, which could also tell why the "raptors" are, once again, unplacable I suspect - the whole paper is an indel phylogeny and accipitrids at least are notorious for having the most strongly rearranged avian genome seen to date). At any rate, I think I need to read one more major paper and then I can start off, but since that one is a caveat emptor one, we'll see. Dysmorodrepanis 19:24, 11 November 2006 (UTC)
I'm basically illiterate when it comes to neornithine classification, so I'll defer to your judgment as to the content of the page (which I do think is a good idea). If it helps, the Dinosaur classification article may work as a template.Dinoguy2 21:51, 11 November 2006 (UTC)

Required Clean Up

There is quite a bit of vandalism on the page, much of which includes false information suggesting that birds came from reptiles. The only time humanity believed this was during the time in which we were foolish enough to believe in Macro-Evolution. The theory has since been proven false, and they are currently pushing to remove it from Biology and Earth Science text books. As such, we should move any information pertaining to evolution into the trivia section of the article, stating that it was once believed, not that it is scientific fact. Wikipedia should be kept as accurate as possible, as to avoid it being shut down by the courts for spreading libel. MarioFanaticXV 22:19, 20 November 2006 (UTC)

This is not trivia and it is certainly not foolish. People pushing to remove it from biology and earth science texts are just that, POV pushers, not scientists. Joelito (talk) 22:29, 20 November 2006 (UTC)
Check Dinosaur-Bird connection which presents the argument (though alternate hypotheses are still lacking and could use somewhat more thorough discussion; if you add, be sure to properly cite your references). In addition, the concept "reptile" is unscientific and it is true that a lot of scientists would love to see it removed from textbooks. Dysmorodrepanis 09:41, 21 November 2006 (UTC)

Evidence from analysis that birds evolved independently of theropods

Kurochkin (2006) showed that the characters that birds share with theropod dinosaurs are convergent with those of theropods. He concluded that the clade Sauriurae (Archaeornithes + Enantiornithes) shares a number of characters with theropods, suggesting that sauriurines evolved from theropods in the Late Jurassic, and that the clade Ornithurae and Protoavis (which is placed in its own subclass, Praeornithurae) evolved from an archosaur ancestor in the Late Triassic. The suggestion that birds evolved independently of theropods is supported by embryological studies showing that the finger structure in birds is II-III-IV, in contrast to the I-II-III finger structure in theropods.

Within a few years, paleontogists will accept this hypothesis, with more fossil birds from the Mesozoic yet to be found, described, and named.

This paper also sheds new light to Protoavis texensis Chatterjee, 1991. This paper includes Protoavis in a cladistic analysis. In Kurochkin's phylogenetic analysis, the characters that unite Protoavis with Ornithurae are:

1. heterocoelous cervical vertebrae. If taken to mean completely heterocoelous vertebrae (as to distinguish neornithines from enantiornithines), absent in Confuciusornis, Archaeorhynchus, Yixianornis, Gansus and Ichthyornis. 2. voluminous tropibasal braincase. I don't know what tropibasal means, though no non-ornithurine Mesozoic bird braincases besides Archaeopteryx have ever been measured volumetrically. 3. reduced postorbital. Absent in Confuciusornis. 4. closed temporal fenestrae. Absent in Confuciusornis, correlated with previous character. 5. narrow elongated coracoid. Also in enantiornithines 6. mobile articulation of the scapula to the coracoid through a fossa in the coracoid and a prominence on the scapula. Absent in confuciusornithids. 7. deep renal depressions on the internal surface of the ilium and sacrum. Absent in Confuciusornis, Patagopteryx, Yixianornis, Apsaravis, hesperornithines and Ichthyornis. 8. fusion between both ends of the third and fourth metacarpals. Absent in confuciusornithids, Archaeorhynchus and Hongshanornis. 9. plantar shift of the third metatarsal in the proximal part of the foot. Absent in confuciusornithids, Archaeorhynchus and Patagopteryx.

The abstract of this paper reads:

The hypothesis of the direct origin of birds from theropod dinosaurs has recently become widespread. Direct sisterly relationships between theropods and birds were assumed in the basis of random and formal synapomorphies, such as the number of caudal vertebrae, relative length of the humerus, and flattening of the dorsal margin of the pubis. In essence, this hypothesis is supported by the characters of theropods and birds, such as the presence of feathering, furcula, uncinate processes of ribs, pygostyle, double-condyled dorsal joint of the quadrate, and posteriorly turned pubis, which are recognized as homologies. Until recently, these characters have been regarded as avian apomorphies; however, they are presently known in various coelurosaurian groups. At the same time, they occur in various combinations in the Dromaeosauridae, Troodontidae, Oviraptoridae, Therizinosauridae, and Tyrannosauridae. None of the theropod groups possesses the entire set of these characters. This suggests that theropods and birds acquired them in parallel. Theropod dinosaurs and Sauriurae (Archaeornithes and Enantiornithes) show a number of important system synapomorphies, which indicate that they are closely related. Ornithurine birds lack such synapomorphies; however, their monophyly is supported by a large number of diagnostic characters. The hypothesis of independent origin of Sauriurae and Ornithurae is substantiated; the former are considered to have evolved from theropods in the Jurassic, while the latter deviated from a basal archosauromorph group in the Late Triassic. The hypothesis that birds existed in the Early Mesozoic is supported by the findings of small avian footprints in the Upper Triassic and Lower Jurassic of different continents.

While proponents of the alleged theropod origin for birds dismiss Kurochkin's paper as a phylogenetic ruse, saying that Protoavis is too poorly preserved to be relevant to the way the avian family tree is phylogenetically reconstructed, proponets of the thecodont origin for birds agree within Kurochkin. So does Sankar Chatterjee.

Scientists have thought that birds colonized the Americas in the Cretaceous, but the discovery of Protoavis suggests a Triassic colonization of the Americas by birds.

Kurochkin, E. N., 2006, Parallel evolution of theropod dinosaurs and birds: Zoologicheskii Zhurnal, v. 85, n. 3, p. 283-297.

Nope, that refers to the less-than-scientific pooh-poohing of Protoavis. There are but few truly scientific analyses of the material, of which those of Witmer and some contributor to EvoWiki stand out, and they focus not really on the bad preservation (one has to work with what one gets, after all) but on the complete lack of evidence that these remains were found in association. According to these, Protoavis is a chimeric non-species composed of archosaurs and just maybe primitive dinosaurs. This would render Kurochkin's analysis pointless, but for entirely other reasons than outlined above. See the Protoavis article for what non-avian archosaurs its bits and pieces may be attributed to.
I think the treatment of Protoavis by the scientific community is shameful. Witmer's analyses on it stands out for its fairness; even though P. is quite fringe and controversial at least, it deserves more than an off-hand dismissal. For example, the vertebrae are best explained as being from an avicephalan diapsid, which bears its name with much justification (although only the most radial theories would consider it anything but convergent evolution)
Interestingly, Chatterjee himself would strongly object to use of his pet to refute an evolutionary theropod-bird relationship. Dysmorodrepanis 21:58, 24 November 2006 (UTC)
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