"Dan Luke" wrote in message
...
"Gary Drescher" wrote:
pigeons ... follow roads.

That doesn't mean they're using pilotage. The pigeons are carried along
the roads in cars to the release points. How would they recognize a
route from the air they had traveled (and probably not seen) only on the
ground?

Birds are capable of magnetic navigation.
http://www.gi.alaska.edu/ScienceForum/ASF3/345.html
Most likely the pigeons are able to sense and store the route they
travel to the release point, and then retrace it home.

You raise a good question. It's conceivable that the pigeons identify
landmarks from the ground that they can recognize from the air. But not
having read the road-following study itself, I can't really discuss it
intelligently. Offhand, though, I'd be skeptical that a stored magnetic
route (fly heading 053 for 220 meters, then 072 for 570 meters...) could be
precise enough that the pigeons would stay above a road and turn at
intersections, even following rotaries. (And the pigeons would need a
source of distance information, as well as heading information--perhaps
derived from timers and accelerometers, or visual cues.) A system
incorporating both pilotage and magnetic tracks is certainly a possibility.

--Gary

--
Dan
C172RG at BFM
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