Looking at Birds in a Whole New Spectrum

Shipud writes "Historically, bird species are classified using may different indicators, including plumage colors. Also, plumage variation has figured heavily in description of similarity between species. In a recent article in PNAS, Robert Bleiweiss shows that if we look in the ultra violet spectrum, birds species which seem similar, or are even considered related based on plumage colors, appear quite different. Quite a few theories regarding supposedly sympatric (sibling) species would have to be re-checked now. And yes, birds can see in the near UV spectrum, which is invisible to humans."

Comments

Wonder what else we could find..

[BlackCobra43]

..using other parts of the spectrum? There's just so much we have left to learn about the world..

Looking at Birds in a Whole New Spectrum

[daviq]

They also look differently in the electromagnetic spectrum.

Re:Looking at Birds in a Whole New Spectrum

[GeckoX]

How is that a troll?

Really now, any moderator care to explain that?

There is actually a valid point to that statement, whether correct or not.

Hoffa!

[mister_llah]

That's why we could never find Hoffa's body, they covered it with UV paint!

Interesting but pointless perhaps?

[GeckoX]

I'm sure there are many many ways we could look at different species. Through a sepia tone filter we could surmize that penguins are siblings of seagulls. We could speculate for ever.

While this is interesting, it really doesn't appear to me to make sense to try to determine lineage and ancestry via visual means. I'm sure there is a lot of info we can learn in other areas using this technique.

However, why use this for lineage/ancestry when we have DNA that, rather than speculate about the pretty colors we can't really see, we can actually make some scientific qualifications about.

I'm thinking the article may be extracting more from this technique than it is actually intended to cover.

Re:Interesting but pointless perhaps?

[torpor]

However, why use this for lineage/ancestry when we have DNA that, rather than speculate about the pretty colors we can't really see, we can actually make some scientific qualifications about.


Having a "UV-spectra"-organized taxology (is that the word?) for birds might serve to back up/support industrial DNA techniques.

or, in short, "you got my eyes!"

Re:Interesting but pointless perhaps?

[Anonymous Coward]

You were looking for the word "taxonomy", but you weren't too far off!

Re:Interesting but pointless perhaps?

[TapeCutter]

DNA can only tell the difference between known species that are very closely related. Many birds have diverse plumage in, what we think, is the same species. Birds pay alot of attention to plumage when picking a mate, the FTA gives an example of how speciation may come about because of UV's role in sexual selection. The research should be followed up to see how large UV's role is. Maybe it will settle some long running Taxonomy disputes but there needs to be more research into the suspect breeding habits, Taxonomy is based on more than just the plumage (think domestic pidgeon).

Nature does not seem to have such precise groupings, it has a huge range of individual organisims with thier own unique DNA. What happens to the "common-sense" notion of species when applied to asexual organisims? In the case of something like a virus we even get confused about how to distinguish between "life" and "non-life".

The bottom line is that the concept of a "species" is a category made up by humans, not a law of nature. Sex, clan and species are human categories that are important because of very deep phycological reasons.

funny nobody studied this sooner

[museumpeace]

Its been known for over a decade that flowers have a surprising degree of UV variability, to which pollinators [but not humans] are sensative.
e.g.:
http://www.naturfotograf.com/UV_flowers_list.html
http://www.bbg.org/gar2/topics/wildlife/2000su_bum blebees.html

Re:funny nobody studied this sooner

[Frumious Wombat]

Actually, well over. When I was a kid 30-odd years ago, I had some time-life books with a picture of flowers in UV, showing how the common buttercup wasn't uniformly yellow, but had dark patches on the petals in UV. I'm surprised that nobody spent the time to photograph some other common things in UV, just to see.

Is this just a case of the difficulty of UV photography (quartz lenses, and expensive filters), or didn't anybody think it was worth the time?

Re:funny nobody studied this sooner

[museumpeace]

Good question. You'd think 30 years of taking UV pictures of flowers would eventually expose the occasional bird in a frame or two.

Interesting, and not at all pointless

[TripMaster Monkey]

The important thing to remember is that birds see in the near ultraviolet, so when we look at birds in that manner, we are seeing them as they see themselves and each other.

Re:Interesting, and not at all pointless

[Anonymous Coward]

Ahh, kind of like they mentioned in TFA.

Re:Interesting, and not at all pointless

[GeckoX]

I wasn't contradicting the fact that it is interesting to be able to look at birds in a manner closer to how they see themselves.

Of course that is not pointless.

The article however leads one to believe that this will allow them to properly distinguish relations between species, which may or may not be true. Regardless, it is not a known way to do this, and there is another way that we _know_ can do this.

As another poster mentioned, this could be used to back up DNA findings.

Now that I've argued again what the article had to say, have you anything of your own to add?

Re:Interesting, and not at all pointless

[TripMaster Monkey]

The article however leads one to believe that this will allow them to properly distinguish relations between species, which may or may not be true.

Well, this pretty much dovetails (forgive the pun), into my earlier post. It stands to reason that examining birds in the near-UV to which they are sensitive will help to more properly distinguish relations between species, since this is one of the mechanisms the birds themselves use.

From TFA:

I describe an avian example of an interspecific phenomenon in which related sympatric species that appear similar to humans (sibling species) differ dramatically in the UV. Both UV video images and physical reflectance spectra indicate that the dorsal plumage of the tanager Anisognathus notabilis has a strong UV-limited reflectance band that readily distinguishes this species from its sibling congener Anisognathus flavinuchus. The main human-visible distinction between A. notabilis (olive back) and coexisting A. flavinuchus (black back) also occurs among different geographic populations of A. flavinuchus. Notably, however, olive- and black-backed taxa interbreed (differentiated populations of A. flavinuchus) unless the additional UV distinction is present (A. notabilis vs. A. flavinuchus). Thus, UV-based reflectance can be an essential component of plumage divergence that relates to reproductive isolation, a key attribute of biological species.

Birds don't have the luxury of DNA tests, but they've been using this method successfully for millennia. An added bonus is that it's much cheaper than DNA testing.

Hope this clears things up for you.

Re:Interesting, and not at all pointless

[Anonymous Coward]

Master of stating the obvious and ignoring the point.

What a condescending prick.

'ow about that Norwegian Blue?

[McBainLives]

Beautiful plumage!

Re:'ow about that Norwegian Blue?

[Sierpinski]

Yeah you can usually find them pining for the fjords.

I was studying them once when a moose bit my sister.

No really...

Re:'ow about that Norwegian Blue?

[Anonymous Coward]

The plumage don't enter into it. It's stone dead!

Of course you have to consider...

[scholzie]

Doppler shift may cause the genetic links between african and european swallows to become obfuscated. However, by measuring the relative red shifts, we might finally settle which one is faster...

Re:Of course you have to consider...

[lurch_ss]

We also have to determine how many coconuts they can carry.

Re:Of course you have to consider...

[superstick58]

How do you mean faster? Is the swallow unladen, or is it carrying a coconut under its dorsal guiding feathers. In which case, how does it overcome the weight ratio? Are two swallows together faster than one?

Re:Of course you have to consider...

[GeckoX]

Wow, you really killed that one ;)

sympatric != sibling

[vitamine73]

I'm not sure this is what the poster meant, but it is implied by the text! Sympatric species (or more precisely populations...) occupy the same area at a given time. Populations that do not occupy the same area are called allopatric.

On the other hand, the notion of sibling species refers to a phylogenetic tree, they are species that who share an exclusive most recent commont ancestor. They are more often called sister species.

So, yes, this new technique could be very useful to distinguish between cryptic (that look the same in practically every way) species that live in sympatry (and allopatry for that matter), but they need not be sibling for this to matter!

Re:sympatric != sibling

[Shipud]

Submitter here: yup, my bad. Thanks for the correction and clarification there.

BTW, My original headline was "Norwegian UV, lovely plumage"

this is fascinating

[VolciMaster]

show's how little we really see as humans. Viewing things under 'alternative' or filtered spectrums helps find all sorts of stuff (think forensics, and not just CSI). It's used to find cracks in materials. In fact, isn't mass spectroscopy used to determine what you're actually looking at based on light wavelength that is absorbed/reflected/diffracted?

How much of a difference will this actually make in classification, though, since we classify based on sensed differences, size, colors, etc. If we can't see the differences because of limitations in our eyesight, it doesn't necessarily mean that the groupings are incorrect.

Timely

[Mark of THE CITY]

Last night, I saw The Wild Parrots of Telegraph Hill, http://wildparrotsfilm.com/ again. The red-crested conyers will not mate with a blue-crested conyer. Now I wonder if it's something I can't see...

I found out the cheapskates seamed my Suit wrong.

[purduephotog]

When I was married last month my suit had been 'fixed' with a cheap fabric that was not the same as the original material.

This fabric reflected IR light at a different % than the rest of the material, resulting in every photo having 1 black arm 1 grey arm.

(I'm using a modified digital Rebel that had the IR filter removed and replaced with an IR pass filter).

http://www.jasonandelizabeth.net/JasonElizabethWed /CRW_8244_19.html

I for one would like to welcome...

[OneDeeTenTee]

...our ultravioletly differentiated avian overlords.

Added ability in humans

[RobertB-DC]

I remember in a Slashdot story a while back about tetrachromats, the idea was floated that humans might someday, using genetic engineering or gene therapy, be given the ability to see in wavelengths previously available only to scientists (and, of course, to Geordi). I think it would be amazingly cool to acquire the ability to see previously hidden details -- of birds, flowers, boobies -- even if it did come at the expense of properly interpreting certain traffic signals.

Re:Added ability in humans

[shawb]

There was a student in my high school physics class who could see a bit into the IR. The teacher had a presentation and had something that we shouldn't have been able to see, but the kid could see it. Although I'm guessing that he wasn't tetrachromatic so much as just had a slight offset in the red receptor pigment. I think it would be trivial for a small mutation to change the pigment. IIRC, organic pigments are "tuned" to a particular frequency by a protein chain that hangs off the main cluster which alters the harmonic frequency, similar to how a longer guitar string will have a lower resonant harmonic frequency.

Re:Added ability in humans

[SimilarityEngine]

I think it would be trivial for a small mutation to change the pigment.

This raises the question: what selective advantage would IR-sensitive (or UV-sensitive) eyes give you? Colour vision is fascinating stuff indeed - especially to me, being colourblind (just like my brother and grandfather). I envy 'tri-chromats' sometimes, and then an article like this comes out and reminds me that we're all in much the same boat... :-)

nearly...

[Anonymous Coward]

i think you may be referring to atomic absorption spectroscopy, or another related form of (electromagnetic) spectral analysis - based on the absorption lines of the sample, you can tell what's in it.

mass spec is entirely different - a compound of interest is fed into the mass spec machine, ionised and fired through a magnetic field onto a sensor such as a photographic film. information on the structure can be found by noting the positions at which the ions hit the film. (this is overly simplistic)

sp

[Mark of THE CITY]

conure