Scientists Discover That Puffin Beaks Are Fluorescent (www.cbc.ca)

A scientist in England discovered that the bills of Atlantic puffins glow like freshly cracked glow sticks when under a UV light. CBC.ca reports of how ornithologist Jamie Dunning stumbled upon the discovery: Dunning normally works with twites, another type of bird, but he had been wondering if puffins had Day-Glo beaks for a while, since crested auklets -- seabirds in the same family -- also have light-up bills. So one January day, while having a "troubling" time in the lab, he threw off the lights and shone a UV light on a puffin carcass. "What happened was quite impressive, really," he said. The two yellow ridges on the puffin's bill -- called the lamella and the cere -- lit up like a firefly. And it's real fluorescence, Dunning emphasizes: something about those parts of the puffin bill is allowing that UV light to be absorbed and re-emitted as a bright glowing light.

The fact some birds have this quality and some birds don't indicates the fluorescence certainly has some use for the puffins, Dunning said, but he's not sure what that use might be. "The bill of a puffin is forged by generations, hundreds and thousands of years, of sexual selection. There's a lot going on there. That's why it's so colorful and pretty." But the radiant color is almost certainly not being used as a headlight, he said. He said whatever's making the beak glow is reacting with the UV light waves, and those light waves aren't around in the dark.

Comments

Tetrachromats

[ChrisMaple]

Contrary to the claim of the article, there are some human females with tetrachromatic vision.

Why are the images in the article of such poor quality?

Re:Tetrachromats

[AC-x]

Contrary to the claim of the article, there are some human females with tetrachromatic vision.

Indeed, although their 4th color receptor always lies somewhere between red and green, which gives better color differentiation but doesn't extend the range of visible colors like birds' UV tetrachromacy does.

Re:Tetrachromats

[PPH]

This is slightly different than tetrachromacy. Birds can see into the UV range. But the puffins' beaks are fluorescing in the visible (to humans) spectrum. UV reflectivity is a different thing and that would result in patterns not visible to humans being perceived by birds. But that wouldn't be testable using the methods proposed in TFA. You'd still need a camera with a UV sensor to record UV reflective patterns.

Since this fluorescent effect only presents itself under low visible light/high UV light conditions, the question is: where does one find such an environment? The answer might be; under water. Short wavelength light penetrates water to a greater extent than longer (redder) light. And since puffins feed under water, this effect might be useful to attract prey.

Re:Tetrachromats

[R3d M3rcury]

Since this fluorescent effect only presents itself under low visible light/high UV light conditions, the question is: where does one find such an environment? The answer might be; under water.

I dunno. I can think of a few nightclubs/discos with that combination...

Re:Tetrachromats

[PPH]

nightclubs/discos

Same motivation at work here: attracting prey.

No mystery

[physicsphairy]

"The bill of a puffin is forged by generations, hundreds and thousands of years, of sexual selection. There's a lot going on there. That's why it's so colorful and pretty." But the radiant color is almost certainly not being used as a headlight, he said. He said whatever's making the beak glow is reacting with the UV light waves, and those light waves aren't around in the dark.

Your laundry detergent, highlighters, even paint on coke cans all have UV dyes in them. The reason is not because humans can see in UV or because they need these objects to glow in the dark. The dyes make them appear artificially bright during the day by emitting the converted UV light in addition to the reflected visible light. In as much as brightly colored beaks are important for sexual selection, the fluorescent pigments are part of the trick.

you could use this for navigation

[goombah99]

The sun's position in the sky is useful for navigation. Except when it's a heavy cloud day like happens in alaska a lot. There's lot of light but now you can't find the position of the sun. But there are two signals that can still tell you where the sun is located. One is polarized light. Since scattering depolarizes, only the direct sun light retains any residual polarization. But this is a very faint signal. It's thought that viking calcite stones used this and some people think pigeons might be able to see light polarization. Still it's not a robust signal.
The other signal is UV light. UV is absorbed and scattered more heavily on a cloudy day. THis means that proportionally, what UV light does make it through is mainly unscattered and thus came straight from the sun.

If you have a flourescent card you can look at amd move round you can maximize the brightness when it's facing the sun. However to do that you have to always keep your head at exactly the same angle to the card othewise you are measuring the lambertion scattering angle of a surface relative to the angle you look at it not the normal incident angle of the illumination source.

SO if your eyes are fixed relative to you beak and you can see both sides of your beak you can see which side is flourescine more as you point it in different directions. when both sides are the same brightness you are pointing at the sun.