Does anybody have an ideas why? I mean, I wasn't really hallucinating, I didn't take too much. I could always truely find north or south. I couldn't tell what was north or south, but I could draw the line, always.
Am I crazy? I mean, I'm not saying I'm a bird, but...
One theory is that the phenomenon is always there but that that visual layer is tuned out, just how with practice you can tune into many visual layers: you can learn to see floaters, the white blood cells moving through the capillaries in your retina, your own heartbeat, noise in the image, etc.
It may serve some function yet to be discovered. At the very least, it is beautiful.
I found that I was able to see Haidinger's brush infrequently. One experiment (which I sadly cannot remember a citation for) suggested that lines in the sky would point north/south.
Also, I forgot to mention that the lines would curve around the light of large stars. It was almost like the oval notches/holes in wood grain. Only the large/visible stars did this.
But, you can probably predict what a magnetic field looks like away from the point of measurement, I.e. the eye. What is fascinating to me is that they could potentially be learning to deal with manmade magnetic fields, adapting to human culture in a possibly novel way.
I seem to have a very good intuitive sense of direction. When I lived in Ottawa, though, I used to always get lost when I hit the river. It took me years to figure out what the problem was. The river runs roughly east west and so all the signs say "East" or "West", but it's actually in the shape of a V. Most of the time it's running NW/SE or NE/SW. Every time I hit the river, I'd consciously think that I'm going East/West when in reality I was going in a completely different direction. It really threw me off.
I think people are more attuned to direction than they think. Direction of the sun, time of day, landmarks, direction of shadows, position of moss on trees, etc, etc. After years and years of seeing it, your brain get's pretty good at orienting you -- even if you don't consciously understand it. These days, I try not to reason about my orientation, but rather guess. I tend to have better results.
The point is that magnetic field lines are a convenient diagrammatic tool, but don't have a direct correspondence to any physical reality. It's just like the way we sometimes draw electromagnetic radiation as a sine wave, but try as you might you won't ever observe little squiggly sine waves in physical reality.
Magnetic field lines correspond as much to physical reality as anything possibly can. https://physics.stackexchange.com/a/80913
Also here's a trippy video: https://www.youtube.com/watch?v=rUZsojDdEbE
Those lines are entirely conceptual.
Even though I am open to alternative explanations, I would say it is also possible, that your knowledge of where north and south is - and your knowledge about the magnetic field - might be enough as an rational explanation.
So to prove - you would need to be able to do the same in an enviroment, where you do not know the directions ...
...am I really the only one who thought about whether this might contribute to why power lines are so attractive for birds to perch on?
It would likely overload the birds senses and not be a pleasant experience.
What a cool possibility overall!
If so, I wonder if one could discourage birds from hitting windows by arranging for a strong magnetic field outside the window?
There are ways to discourage birds from flying into windows, but they often make the window less useful to humans.
First since I've been doing some Software radio stuff of late, I'm wondering if there is a way to build a chemical detector for magnetic fields that would allow one to pick up signals without a giant magnetic loop antenna. The paper (linked in another comment) suggests that the frequency response is low (1uS to 100uS) so it would not be a high bandwidth link :-).
The other is what happens when the poles swap? Do the birds commit mass suicide as they fly north for the winter and south for the summer?
I believe that a polarity change in fewer than 100 generations would be challenging for most species that see or use the magnetic field to adapt.
Just wondering. I'd read about theories regarding iron in the beaks and whatnot. Sounds cruel, but why not (a) train the bird to select the magnet, then (b) remove beak and check if it can still do the trick, or (c) remove eyes and see if it can still do the trick.
I'm not entirely sure, though, that (a) has been accomplished. Can't find anything on it.
It sounds cruel because it is cruel.
Reminds me of this quote from Dostoevsky's "The Brothers Karamazov":
Tell me yourself, I challenge your answer. Imagine that you are creating a fabric of human destiny with the object of making men happy in the end, giving them peace and rest at last, but that it was essential and inevitable to torture to death only one tiny creature ... and to found that edifice on its unavenged tears, would you consent to be the architect on those conditions? Tell me, and tell the truth.
Throughout history we have been known to send our sons and daughters to die in large numbers to first gain, and then protect, basic freedoms. And for other, less honourable, reasons as well...
Returning back to science, a utilitarian could easily make the case that, if it is impossible to avoid, being cruel to bird for the sake of humanity may be a tradeoff worth making.
Humans have gained great powers of number calculation, but I suspect that our greatest power and obsession has always been story-telling. We tell stories to each other and ourselves, and those stories form the basis of our ethics and morality.
Which is why I think utilitarianism always feels cold and unsatisfying; it doesn't play well as a story.
The field of ethics essentially considers how to build and analyse arguments. Ethics generally does not make decisions; and it's not a flowchart you can follow to get a yes/no answer, either. People often use the world "unethical" as-if it is a proper adjective, meanwhile it actually refers to themselves having concluded that the act/object is not ethical within their reasoning; it's not an actual property of an act or object.
Much like broad philosophy, it's a language for expressing thoughts. It doesn't think for you. Or, if you like, mathematics is a language for expressing some other thoughts. Mathematics doesn't solve problems for you, or prevents you from writing 3+1=5.
Before talking about Utilitarianism, we first must talk about it's parent Consequentialism. The basics are this; Consequentialists state that the outcomes of an ethical decision should leave the outcome in a superior moral position. This is opposite of such systems like Kantian Virtue Ethics that state a more a priori value on the decision, even if the outcome is negatively affected. Honor might be a Virtue Ethic, since you would always act honorably even if the situation makes that a bad course of action.
Utilitarianism is a balance point between two Consequentialist children: Ethical Egoism and Ethical Altruism. Both (respectively) examine the outcome based on the individual making the decision, and the rest of the situation outside of the individual. Combining both Utilitarianists examine the outcomes of both the individual and the surrounding environment when determining which course of action to take.
tl;dr: Ethics are amoral systems of decision making that tell you where and how to apply your morals.
I disagree, the conventional and I think the more widely understood meaning of 'morals' would be 'principles' or 'standards of right and wrong'. I think the term 'values' would do just fine.
Are you making that argument? Your comment seems an extreme example of writing that uses the passive voice.
To answer your question, while in my personal life I take a more deontological (Kantian) moral approach, if I were in a policy making role I'd take the pragmatic, utilitarian road; that bird would be sacrificed if it really did help advance science. Ecce homo.
The pigeons were trained to go to one end of the tunnel if the coils were switched on, generating a magnetic field, and to the other if they were switched off, leaving Earth's natural field unperturbed. "I was pleasantly surprised. The pigeons were very fast learners," says Mora, now at the University of North Carolina in Chapel Hill.
Their skills were impaired, however, when the researchers attached magnets to their upper beaks, and also when the upper beak was anaesthetized. This suggests that their ability is down to the presence of magnetically sensitive material in this area, the researchers report in this week's Nature1."
This sentence makes me wonder: are they docile because it genuinely calms them, or are they entering a sort of helpless automatic panic mode, like "OMFG no escape, can't fly, can't move"?
The latter sounds like the bird is getting a terrifying experience.
Looks like the humane way to test, according to the article cited above, is to affix magnets to the eyes/beak to see if it disrupts anything. In any case, in retrospect, I personally feel my suggestion to remove the beak is more cruel than removing the eyes. Both are hideous to contemplate. But, a bird without a beak? That's just a miserable thing to imagine.
- Mary Shelley’s Frankenstein
I would hope science has evolved were we could devise a test without having to resort to such a method. Maybe I am too far removed from such things, out of sight out of mind.
They would probably combine with sunlight to get the real orientation – an approach which would continue to work with a flipped magnetic field.
And then they wouldnt be able to see parts of the field they are not currently in. Magnetic fields don't radiate anything, they ARE the radiation. It's like trying to see a laser that is not pointed at your eye. It's there, but it cant be detected because no photons from it are hitting your eye.
The atmosphere is known to diffuse the vectors of electromagnetic radiation. That’s how we get blue skies and red sunsets. Who says it’s not having the same effect on earth’s magnetic fields
Likewise the effects of the magnetic field interface with earth’s atmosphere.
For example Earth's magnetic field deflects solar wind. The solar wind interacting with the magnetic field transfers some of its energy into earth’s atmosphere.
> This chemoreceptor patent-proposal is kicking my ass. Hundley won't let me down until it's done. Hardly worth filing for, in my opinion. Who wants to smell the difference between xenon and radon?
At some point this really starts to sound ridiculous.
Because it's in their eyes, it would have a visual interpretation. And some evolutionary advantage to that visual advantage, else the cells could be anywhere (unless there's a biochemical similarity to cones?)
However, a field isn't like photons hitting the retina. It would probably be a new colour, which we can't imagine, but I'm asking where that colour would appear, to indicate the field.
Perhaps a faint fog, varying in strength with direction - like the sky at dusk and dawn.
Perpendicular to that direction light "wiggles" on it's way from origin to destination.
The direction of the 'wiggle' is the polarization of the light.
Unpolarized light wiggles in every direction while polarized light only wiggles in one.
Certain things (like how the sun shines on the sky) creates polarized light naturally.
The earth's magnetic field DOES NOT polarize light.
Birds have a protein in their eyes that uses blue light + the earths magnetic field to visualize the magnetic field around them.
Similar to visualizing the polarity of light, we lack the ability to visualize magnetic fields, making both foreign concepts.
That allows them to figure out the position of the Sun when it is not visible due to clouds, which is indeed useful for navigating.
But what this article is about is seeing the Earth's magnetic field.
At least some migratory birds are able to detect both their longitude and latitude  , which requires more than just knowing where the Sun is.
Humans have been able to figure out latitude for a very long time...at least as far back as the ancient Greeks, and probably much farther back.
Longitude, on the other hand, eluded us until we were able to make reasonably accurate clocks. For sea navigation, that wasn't until the 18th century, long after we had compasses and knew about polarized light.
I was just able to see the effect for the first time using this image  full screen on my phone :) Brightness up, screen rotation off, hold out the phone and turn it like your steering a car. Jumped right out at me. It's always at the center of my vision, so if I look around the screen as I'm turning, it follows. The yellow always points to the longer edges of my phone. It's hard to hold it in view when not turning though.
Can we do an Initial Cryptochrome Offering?
"Birds can see Earth's magnetic fields due to protein in their eyes"
or the original, more clickbait-y title:
"Birds Can See Earth's Magnetic Fields, And We Finally Know How That's Possible"
Also, we changed the URL from http://archive.is/SlcSL. archive.is is an excellent site for archiving, but not for HN submitting, because it's important for readers to see the actual domain. For the same reason, we don't allow link shorteners.