How many avian orders are there? (2 Viewers)

[Jim M.]

I feel the base attempt of doing orders by time or generations passed is just not right. To some extent, I like the much older test: you know one when you see one. In that context, I would go more with AOU than with the Clements/ebird list: hummers, swifts, nightjar-owlets and nightjars in different orders. I am not sure if Potoos need to be split if that is done -- if so, I will live with the result.

Niels

They are still in different families under the single order proposal. In any event, are you claiming you see no strong similarity between a nighthawk and a swift? Both have cigar-shaped bodies, sickle-shaped wings, wide mouths, short beaks, do not perch (nighthawks sometime rest on objects, but not what I'd call perching), and make their living hawking insects on the wing.

Hummers obviously are an outlier here. But no taxonomy will perfectly match our field intuitions (and if it did it would arguably be uninteresting).

 

[njlarsen]

Beyond that: when I saw my first Owlet-Nightjar, it felt like a really different bird than a Nightjar

Niels

 

[King Edward]

I would argue that it is better to let evolutionary history tell us how many species are in an order, rather than to have a preconceived idea of how many species should be in an order!

It's always going to be somewhat arbitrary where the lines get drawn, but as a general principle I strongly agree. It's normal in pretty much any biological groupings that you tend to get a small number of very large groups containing most of the species, and a large number of small groups containing very few species. An attempt at a natural classification should reflect this, rather than trying to split the big groups and lump the little ones for convenience.

 

[Jim LeNomenclatoriste]

(And I would find your argument against small orders a bit more compelling if you were not also advocating separate orders for ostriches, rheas, etc.! )

One order for Palaeognathae, why not, after consideration. What could be the arguments in favour of an enlarged struthioniformes, the number of toes (lol)?

 

[Jim M.]

Not to beat this to death, but the SACC original proposal and first comment give an excellent overview of the pros and cons of the two proposals to make Caprimulgiformes monophyletic (splitting vs. expanding): http://museum.lsu.edu/~Remsen/SACCprop703.htm

 

[Kirk Roth]

They are still in different families under the single order proposal. In any event, are you claiming you see no strong similarity between a nighthawk and a swift? Both have cigar-shaped bodies, sickle-shaped wings, wide mouths, short beaks, do not perch (nighthawks sometime rest on objects, but not what I'd call perching), and make their living hawking insects on the wing.

Hummers obviously are an outlier here. But no taxonomy will perfectly match our field intuitions (and if it did it would arguably be uninteresting).

I might agree with Niels that "difference" may be a more useful defining quality for Orders than relatedness might be. I'm not even all that convinced that embeddedness is a problem - because every evolutionary unit has to start somewhere - just because a hummingbird evolves from the "middle of the pack" doesn't necessarily mean that all those ancestral characters retained by the "non-Trochilid Caprimulgiformes" (see how un-useful?) are somehow more of a difference.

But on a more pedantic note, I've got to say that the differences between Apodidae and Caprimulgidae have been easily recognized for a great deal of time. Further, I have never before heard of goatsuckers described as having "cigar-shaped bodies," (Jim, what kind of broad-chested cigars do you smoke? ) and also nighthawks, Chuck-will's Widow, Whip-poor-will, etc. certainly perch on small branches and the occasional phone wire in the U.S. at least.

 

[Jim M.]

But on a more pedantic note, I've got to say that the differences between Apodidae and Caprimulgidae have been easily recognized for a great deal of time. Further, I have never before heard of goatsuckers described as having "cigar-shaped bodies," (Jim, what kind of broad-chested cigars do you smoke? ) and also nighthawks, Chuck-will's Widow, Whip-poor-will, etc. certainly perch on small branches and the occasional phone wire in the U.S. at least.

--Of course there are differences between the two groups--that's why everyone agrees they should at least be in different families. (For a more comprehensive summary of the similarities despite the differences in an enlarged Caprimulgiformes see Claramunt's remarks in my link above). But there are even more dramatic field observable differences between a treecreeper and a raven, yet they are placed in the same order by everyone.

--I didn't say "goatsuckers" have cigar-shaped bodies. I said nighthawks did, which can be seen in this image http://aba.org/boy/wp-content/uploads/2012/12/Common-Nighthawk-male-Alex-Lamoreaux.jpg And which is why beginning birders can confuse swifts and nighthawks.

--I've seen nighthawks rest on utility wires, but they always do so resting parallel to the wire--never perching perpendicular to the wire as perching birds do.

 

[Peter Kovalik]

An order is whatever I say it is

a paraphrasing of this title of the Collar's paper

 

[jurek]

I have been wondering recently if we can now come up with a better answer to the question of how many orders of birds should be recognized.

It is a question I wondered for some time, but never had time to work.

Groups in taxonomy like 'order' 'family' 'class' were first created artificially by Linnaeus and later taxonomists. However, there are methods to check objectively whether variation of birds (or any other organisms) really falls into groups of different sizes like orders, rather than just say: lets call it an order, because I like it. There is a sub-branch of math officially called data clustering which does it. It is used from playing on a stock market to diagnosis of diseases, but did not make it yet into ornithology.

This would answer objectively: whether there are groups of species of some size, which are more similar than groups of different size. So, whether differences between birds go smoothly from most similar to least similar species, with no steps in between, or there form objective groups of different size coming in hierarchy, which can be then called 'orders' 'families' etc., or perhaps new names would need to be invented.

Second question would be, if these differences are shared between groups of birds and birds and mammals or other organisms (so, whether an 'order' of birds is so similar as 'order' of mammals, or 'family' of passerines is as similar to each other and dissimilar from another family of passerines, as are 'families' of say, waders.

The third question is naturally, what belongs where and how many these groups are (if they turn to be real).

It would require making a matrix of bird characters (visual or DNA sequences) and applying methods like clustering.

If some birder has mathematics/programming knack, this would be an interesting project. Another question would be, who will supply the data (matrix of differences between birds).

BTW, I consider what I wrote above an original research idea. If somebody wants to follow it, please contact me privately and don't steal ideas without attribution.

 

[Jim LeNomenclatoriste]

Who is taxonomist among you, out of curiosity ?

 

[njlarsen]

Who is taxonomist among you, out of curiosity ?

What does that really mean at this point? Getting paid for being one? If so, at least one of the people on the SACC would not qualify.

In my own case, no I am an amateur.

Niels

 

[fugl]

. . .In my own case, no I am an amateur.

Me too (I'm not even a biologist). So what?

 

[Jim LeNomenclatoriste]

Me too (I'm not even a biologist). So what?

Just to know, it was an innocent little question. Like you I'm not scientist at all. o

What is certain is that taxonomy is all my life but you're much better than me to talk about at all levels.

 

[Mysticete]

It is a question I wondered for some time, but never had time to work.

Groups in taxonomy like 'order' 'family' 'class' were first created artificially by Linnaeus and later taxonomists. However, there are methods to check objectively whether variation of birds (or any other organisms) really falls into groups of different sizes like orders, rather than just say: lets call it an order, because I like it. There is a sub-branch of math officially called data clustering which does it. It is used from playing on a stock market to diagnosis of diseases, but did not make it yet into ornithology.

This would answer objectively: whether there are groups of species of some size, which are more similar than groups of different size. So, whether differences between birds go smoothly from most similar to least similar species, with no steps in between, or there form objective groups of different size coming in hierarchy, which can be then called 'orders' 'families' etc., or perhaps new names would need to be invented.

Second question would be, if these differences are shared between groups of birds and birds and mammals or other organisms (so, whether an 'order' of birds is so similar as 'order' of mammals, or 'family' of passerines is as similar to each other and dissimilar from another family of passerines, as are 'families' of say, waders.

The third question is naturally, what belongs where and how many these groups are (if they turn to be real).

It would require making a matrix of bird characters (visual or DNA sequences) and applying methods like clustering.

If some birder has mathematics/programming knack, this would be an interesting project. Another question would be, who will supply the data (matrix of differences between birds).

BTW, I consider what I wrote above an original research idea. If somebody wants to follow it, please contact me privately and don't steal ideas without attribution.

I can't tell if this is a joke or not, but what you are describing is basically phylogenetics. So you might be a...half century late? on this idea.

 

[Jim Mountjoy]

Not to beat this to death, but the SACC original proposal and first comment give an excellent overview of the pros and cons of the two proposals to make Caprimulgiformes monophyletic (splitting vs. expanding): http://museum.lsu.edu/~Remsen/SACCprop703.htm

I certainly found it very interesting to read Van Remsen's proposal. He basically used the same 'method' that I did of drawing a line at a somewhat arbitrary line through Prum et al.'s phylogeny to see what lineages were distinct taxa at that point. Van did use a somewhat more conservative date, 54 million years ago vs. 52. But even using that early date the potoos, oilbird, and nightjars are easy to support as distinct orders, as the other lineages at that age were all recognized as orders, or multiple orders. (Van did NOT propose lumping cuckoos and bustards, even though they were apparently not distinct lineages at 54 million years.) He did promise to submit a proposal to the NACC to recognize the ibises as a distinct order, based on the 54 Ma criterion.

Van also emphasizes, that if you look past the drab well-camouflaged plumage, that the different taxa (potoos, oilbird, hummingbirds, etc.) are very different in morphology. I am not entirely comfortable with this line of reasoning, as I would be willing to split such ancient lineages even if they were not so obviously different in morphology. However, I do agree that they are pretty darn different anyway. Hummingbirds and potoos seem pretty strange bedmates in the same order.

For those who seem to be arguing that relatedness does not matter, and that a taxon can be recognized when it is seen, I do have to say that I think that this goes against what systematists have been trying to do since 1859. Actually, even before Darwin, systematists have tried to look for some 'deeper' relationship between taxa than just a superficial physical similarity. Hopefully we are getting better at this! If we were relying simply on physical differences to determin what is justified as a distinct taxon, then groups such as Hawaiian honeycreepers or vangas would qualify as multiple families, rather than being a single family or a small portion of a family.

 

[njlarsen]

For those who seem to be arguing that relatedness does not matter, and that a taxon can be recognized when it is seen, I do have to say that I think that this goes against what systematists have been trying to do since 1859. Actually, even before Darwin, systematists have tried to look for some 'deeper' relationship between taxa than just a superficial physical similarity. Hopefully we are getting better at this! If we were relying simply on physical differences to determin what is justified as a distinct taxon, then groups such as Hawaiian honeycreepers or vangas would qualify as multiple families, rather than being a single family or a small portion of a family.

For the part that i bolded (relatedness does not matter) I think it is an exaggeration that either I made or you are making from what I wrote. Exaggerations can be useful to get a point across, or they can come back like a boomerang and hit you in the back.

However, there is some truth to that statement as well. I have been observing and reading about island populations a fair bit, and my take on it is that island taxa going through bottlenecks and deviating selective forces can lead to accelerated evolution. Such taxa can therefore change dramatically in regions of the genome that matters the most, but in a sequence of random genomic regions not look nearly as different because they did not have that many generations of time. This process to me is a little difficult to reconcile with some of the rules of taxonomy as we know them, especially the rule about monophyly. At the level of Species, some taxonomists accept lack of monophyly, while at higher levels it is more difficult to find someone raising a voice of different opinion.

Niels

 

[Kirk Roth]

--Of course there are differences between the two groups--that's why everyone agrees they should at least be in different families. (For a more comprehensive summary of the similarities despite the differences in an enlarged Caprimulgiformes see Claramunt's remarks in my link above). But there are even more dramatic field observable differences between a treecreeper and a raven, yet they are placed in the same order by everyone.

--I didn't say "goatsuckers" have cigar-shaped bodies. I said nighthawks did, which can be seen in this image http://aba.org/boy/wp-content/uploads/2012/12/Common-Nighthawk-male-Alex-Lamoreaux.jpg And which is why beginning birders can confuse swifts and nighthawks.

--I've seen nighthawks rest on utility wires, but they always do so resting parallel to the wire--never perching perpendicular to the wire as perching birds do.

At risk of escalating on a thread that already seems too argumentative for my liking - here is a blog that features several examples of nighthawks perching in all sorts of positions: http://backyardbirdinginsoutheastte...huac-national-wildlife-refuge-common.html?m=1

There are several other examples online, although this one is nice because there are several all on one page. But regardless, none of these are very comparable to the vertical clinging exhibited by most swifts.

Also, the "cigar-shaped body" so often referred to in field guides is almost invariably used to describe the tubular and blunted-at-both-ends body type of a swift such as Vaux's, Chimney, etc. Nighthawks are "front heavy" in body shape and taper or attenuate to a long, not blunt, tail. I'll again state that I've never before heard this referred to as shaped like any sort of cigar, nor like a swift. In fact, out of all the students and birders I've dealt with (mostly eastern U.S.), I've run into exactly zero instances of confusing swifts and nighthawks - although I'm certain it has happened somewhere.

And now that I've said all this, I'm not replying any more on this matter. I hope its obvious that I'm not looking to pick a fight here, but if I came across that way, I do apologize.

I'm not directing this statement toward Jim, but mostly to everyone contributing here - some of the comments/arguments on this thread are starting to look a little snarky to an outside perspective - let's remember to be courteous if we can.

Thanks,
Kirk

 

[Nutcracker]

In fact, out of all the students and birders I've dealt with (mostly eastern U.S.), I've run into exactly zero instances of confusing swifts and nighthawks - although I'm certain it has happened somewhere.

In UK tradition it is cowpats [cowpies] and nighthawks where the confusion lies 3

 

[l_raty]

Also, the "cigar-shaped body" so often referred to in field guides is almost invariably used to describe the tubular and blunted-at-both-ends body type of a swift such as Vaux's, Chimney, etc. Nighthawks are "front heavy" in body shape and taper or attenuate to a long, not blunt, tail. I'll again state that I've never before heard this referred to as shaped like any sort of cigar, nor like a swift.

This is presumably open to interpretation? One species that is classically described over here as having a 'cigar-shaped body' is Cecropis daurica, the Red-rumped Swallow. But, in this characterisation, the tail is excluded entirely from the 'cigar'. (E.g., see this.]
These words would not fit 'our' swifts (Apus spp), on the other hand, most of which 'are "front heavy" in body shape and taper or attenuate to a [somewhat] long, not blunt, tail'.


Huxley 1867 united hummingbirds, swifts, and goatsuckers in a single taxon, noting:

The CYPSELOMORPHÆ, like the Gecinomorphæ, are annectent forms between the Coracomorphæ and the Coccygomorphæ.
The vomer is truncated at the anterior end, and the maxillo-palatines slender and disposed nearly as in the typical Coracomorphæ (? Trochilus).
The sternum is broad and is devoid of a forked manubrium. Its posterior edge may be entire, or may have two excavations on each side.
The furcula has no backwardly directed median process, or only a rudiment of it; and the scapular end of each clavicle is not expanded and T-shaped.
The lower larynx has not more than one pair of intrinsic muscles.
This group contains three very distinct families — the Trochilidæ, the Cypselidæ, and the Caprimulgidæ.
The first two families have a length of the manus and a brevity of the humerus which is peculiar to themselves, being only approached by the Swallows, and in a less degree by the Caprimulgidae.
In both Caprimulgus and Ægotheles the manus is slightly longer than the ulna, and the latter considerably exceeds the humerus in length.
Both the Swifts and the Goatsuckers have a slight rudiment of a vertical process developed from the middle of the furcula. Ægotheles approaches the Swifts more nearly than Caprimulgus does in the form of its palatine bones, and in the absence of basipterygoid processes.

(He did not include Podargus in this group, however. He did not address Steatornis.)

 

[jurek]

Sorry for sounding sometimes very official. Just in case anybody wondered - I don't make my money from birds either.

I can't tell if this is a joke or not, but what you are describing is basically phylogenetics. So you might be a...half century late? on this idea.

Always time to learn something new. So, please, answer the question: having the biggest data set available, which is the best division of birds and of mammals into groups? The best is the one, traditional, where similarity inside groups is biggest and similarity between groups is smallest. And how much it is better from the second-best group? It should be very easy question, since you say it is 50 years going on.

I don't follow phylogenetics closely, but in casual glance it is occupied more with the question 'what is related to what and not to what'. The question is different: 'a what level the groups are most clearly visible'.