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Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
I wouldn't normally post this sort of thing on 4HV but as it has been theorised that pigeons navigate using quantum coherence in specialised cells within the retina to detect magnetic field flux direction anything which affects this mechanism would totally mess up navigation and result in lost birds.
As the mechanism is probably extremely similar to that found in honeybees it would be interesting to see if CCD (aka Colony Collapse Disorder) has spiked in the same area or not during recent years compared to the rest of the UK.
Could also be solar activity but usually fanciers don't fly their birds when there are big flares predicted for this exact reason.
Registered Member #53
Joined: Thu Feb 09 2006, 04:31AM
Location: Ontario, Canada
Posts: 638
The satellite stuff is bunk but I wonder what could make a magnetic field big enough (in volume) to put them off course. I have hear of migratory birds (pelicans maybe) that also used magnetic cells for navigation but I can't imagine what it would take to trick them. Its easy to make a magnetic field stronger then the earth's but the volume it occupies is so small that I wouldn't think that birds would take any notice of them.
Where I am we have problems with migratory birds being put off course and killed by tall buildings that have bright lights on at night (the birds technically kill them selves but the building gets an assist). I wonder if there are are other cues that pigeons use to navigate that haven't been studied. Around here the pigeons are one of the few birds that don't fly into large windows with any regularity, the only think that kills them is cars and their own acclimatization to people and city life.
Registered Member #1134
Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351
Magnetic north has moved significantly over the last few years. So much so, that at least one airport in the states has had to re-paint its runway markers.
Disregarding things like polar wander, pylons, and mobile phone masts, mass disappearances, beachings, or other events, of large numbers of migratory species, seem to be historically quite commonplace. I'm sure somewhere along the line, we will discover a wholly natural reason for it.
Registered Member #5598
Joined: Thu Jul 05 2012, 11:18PM
Location: Llandudno, north Wales.
Posts: 20
Not sure if it's the case but historically we have complete pole reversals! Maybe we are on course for one now? I have just recently been studying these pole reversals that are evident in the sea beds. They are random and thus so cannot be determined as to when they will happen.
Registered Member #2939
Joined: Fri Jun 25 2010, 04:25AM
Location:
Posts: 615
Localised magnetic anomalies aren't all that rare. There's one near where I grew up that makes pigeons fly several kilometers the wrong way before reverting to the correct flight path ( or so I've been told).
Not sure if it's the case but historically we have complete pole reversals! Maybe we are on course for one now? I have just recently been studying these pole reversals that are evident in the sea beds. They are random and thus so cannot be determined as to when they will happen.
Interesting stuff though.
Actually, it has. I forgot the intervals, but it does regularly, and they can see this by looking at the strips on the sea bed, and it seems to occur at regular intervals. Either way, we are very overdue for a pole reversal. A pole reversal would be disastrous in many ways. Hm, I live in Orlando, and magnetic north is almost exactly the same direction as true north.
But I wouldn't be surprised if the reversals are screwing up migration patterns. I once saw a bird with a tag on it crash into my window (this was in Australia). I'm not sure if "bird crashing and breaking window" was covered by the insurance. I was 9, then. It was tagged, though. I think pigeons would be the early warning system for the pole reversal, and I'm sure it's happening/ will happen very soon. Then... the earth will go on an unstable wobble for a while, with wild season changes, possibly a large rise in the oceans, deserts in Russia, and a rainforest in the Sahara. Probably won't happen in our lifetimes, but it would happen over the period of 500 years or so.
Registered Member #1792
Joined: Fri Oct 31 2008, 08:12PM
Location: University of California
Posts: 527
wrote ... I wouldn't normally post this sort of thing on 4HV but as it has been theorised that pigeons navigate using quantum coherence in specialised cells within the retina to detect magnetic field flux direction anything which affects this mechanism would totally mess up navigation and result in lost birds.
You don't even link to the interesting part, the possible "quantum coherence". There seem to be two main theories behind magnetic sensing in animals, with the quantum coherence having to do with small magnetic fields being able to affect chemical reactions and the other dominant theory being magnetic particles which move as the direction of the magnetic field changes.
Those who are interested in this can read about the chemical mechanism in the following. Unfortunately subscription is required for full paper. link
Christopher T. Rodgers and P. J. Hore Chemical magnetoreception in birds: The radical pair mechanism PNAS 2009 106 (2) 353-360; published ahead of print January 7, 2009, doi:10.1073/ wrote ...
Abstract
Migratory birds travel vast distances each year, finding their way by various means, including a remarkable ability to perceive the Earth's magnetic field. Although it has been known for 40 years that birds possess a magnetic compass, avian magnetoreception is poorly understood at all levels from the primary biophysical detection events, signal transduction pathways and neurophysiology, to the processing of information in the brain. It has been proposed that the primary detector is a specialized ocular photoreceptor that plays host to magnetically sensitive photochemical reactions having radical pairs as fleeting intermediates. Here, we present a physical chemist's perspective on the “radical pair mechanism†of compass magnetoreception in birds. We outline the essential chemical requirements for detecting the direction of an Earth-strength ≈50 μT magnetic field and comment on the likelihood that these might be satisfied in a biologically plausible receptor. Our survey concludes with a discussion of cryptochrome, the photoactive protein that has been put forward as the magnetoreceptor molecule.
IEEE spectrum has also recently highlighted some work on isolating the cells which have magnetic sensitivity by applying a rotating magnetic field to a sample of dissolved tissue and searching under a microscope for rotating cells: (video included, no subscription necessary). At least for the salmon that these researchers conducted their test with this result is consistent with the theory that magnetic sensing is done by magnetic particles which move and can be sensed by the animals nervous system.
wrote ... Could also be solar activity but usually fanciers don't fly their birds when there are big flares predicted for this exact reason.
Do solar flares significantly impact earth's magnetic field at low altitude?
Registered Member #1134
Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351
HighVoltageChick wrote ...
Actually, it has. I forgot the intervals, but it does regularly, and they can see this by looking at the strips on the sea bed, and it seems to occur at regular intervals. Either way, we are very overdue for a pole reversal. A pole reversal would be disastrous in many ways. Hm, I live in Orlando, and magnetic north is almost exactly the same direction as true north.
Not quite as regularly as you might think! Precise mapping of the sea floor reveals two reversals in the last Million years (0-1Mya), and Six reversals between 3 and 2 Mya, two of which were very short lived on a geological timescale.
Beware of any sources, especially related to geological events, that claim we are 'overdue' for an event. I know the media loves to throw that word around, especially with anything that can be construed as extinction level, since it sells news. Modern Geologists have spent the last hundred years trying to predict and model events like these, and like predicting the weather, conclusive answers remain out of reach.
Having said that, looking at the recent data, certainly the magnetic field of the earth is changing, and quite rapidly. The movement of magnetic north is speeding up, and if the trend continues, it will end up in Siberia in a short timescale. The South Atlantic anomaly is growing, and other areas of the magnetic field are also changing quite rapidly. Even in light of this evidence, it would be foolish to say "this is the beginning of a reversal", since we have only been accurately observing the field, for what amounts to a geological blink of an eye. Certainty is a very big word in geology.
2Spoons wrote ...
Localised magnetic anomalies aren't all that rare. There's one near where I grew up that makes pigeons fly several kilometers the wrong way before reverting to the correct flight path ( or so I've been told).
I have heard this too, and even detected a local anomaly, which was totally natural!
I was prospecting for Uranium ore in Scotland, in area with a massive suite of mineralization, such as Lead, Bismuth, Copper, rare earths etc. In one of the hills there is a huge deposit of iron ore, which is interspersed with pockets of Magnetite. This was easily detectable with a compass. In fact when I found an outcrop of sufficiently good magnetite (and other minerals, including Uranium), the compass would simply be attracted right to it, rather than north, and was even screwing with the reading on my poorly shielded geiger counter at the time!
In the area in which I live, I have found fist sized lumps of Haematite in the bottom of rivers and streams, along with smaller pieces of Magnetite, so it is a safe bet that even if the earth had a text-book perfect magnetic field to begin with (which it does not) It would not take much iron ore that the surface to distort it.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
Interesting stuff indeed.
There is a controversial theory that "anomalous luminous phenomena" sightings in a given area are associated with the presence of one or more magnetic field anomalies. Essentially a nearby lightning strike or other electrical event adds to the already distorted field and induces TMS phosphenes in the human visual cortex in susceptible individuals.
-A #include"
numerousreferencedpapersinIEEEspectrumsothisisinno
waypseudoscience.h"
Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Mattski wrote ...
wrote ... Could also be solar activity but usually fanciers don't fly their birds when there are big flares predicted for this exact reason.
Do solar flares significantly impact earth's magnetic field at low altitude?
Can you (or anyone else) suggest any other mechanism that might be responsible for pole reversal other than solar flares/other cosmic phenomena?
(Here is a link to one of the 'Electric Universe' websites...I'm trying to be careful here, there is some pseudoscience in SOME of the related theories....Please read this stuff selectively...There is obviously a lot of 'proper science' in this too.)
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Mystery pigeon disappearances
