Navigation is a really tricky thing to test it seems.  There seems to be no question at all that some animals use earth's magnetic field to navigate.  It is well proven that pigeons use it as birds with strapped on magnets which swamp the earth's field result in birds that either do not come home or home very slowly.  But you can take a pigeon and train it to come home always using training flights in more or less the same compass heading to get home.  Then take that bird and release it at a 90 degree or even 180 degree shift in direction home and the bird will still come home in good time.  Knowing compass heading is not enough to explain that.  Not for a release from 200 or 400 miles away from home.   Landmarks also do not explain pigeons coming home.  You can put fogged contacts on them so all they can see is dark and light so they can tell where the horizon is and they come home fine.  But when home they land in the yard and can not find the coop.  Most guys who fly pigeons will tell you to never do a release near high tension lines as the birds will all get lost.  So, I took some untrained birds and trained them by always releasing under high tension lines.  They came home just fine.  So, is it folklore to not release under such lines or did I simply train my birds how to compensate?  An experiment done on humans show they have some kind of compass.  Interestingly humans tend to orient within +/- about 20 degrees of home or +/- about 20 degrees of 180 degrees from home.  I suspect I would be in the latter group as I am always getting lost and have no clue what direction is north unless it is clear and night so I can see the stars or day time and clear so I can see the sun.  So, when you test bees how do you really make sure you are testing if they use magnetic fields?  The problem is they likely use several things and are able to ignore data that does not fit other data.  You could strap on a magnet and find it made no difference at all.  Does this really say that a bee never uses earth's magnetic field or does it simply say that bee had enough different navigation clues that a bad magnetic reading is just ignored?

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