With
the barn swallows back this Spring and being quarrelsome for about 45 minutes
prior to day break, I am reminded that many birds fly long distances and come
back to the place they started.
Pigeons
are a little different in that they are definitely “home birds” and we have
regular competitions where we take them somewhere that they haven’t been before
and tell them to go home. Big money can change hands for the best birds.
It
has long been a question as to how do homing pigeons home? The favorite idea is
that they have a compass stashed away, but exactly where has been the subject
of speculation. No more! Dickman and Wu
of Baylor have cracked it. The BBC has a full report (1) on their recent paper
in Science (2) in which they report that the bird brains have room for a very
sophisticated magnetic field sensor.
Apparently,
each pigeon has 53 neurons that fire up in response to magnetic field changes.
They measured the electrical signals from the individual neurons as the bird
was held in a magnetic field that was varied in direction and magnitude.
Sharks,
whales and bats also use the earth’s magnetic field to navigate by, so this
ability seems to be fairly widespread and leads one to wonder if many men think
that they also can do this, and that is why real men don’t stop driving and ask
for directions. Their success is clearly the reason that their female
passengers demanded that the GPS for automobiles be invented.
- http://www.bbc.co.uk/news/science-environment-17855194
- http://www.sciencemag.org/content/early/2012/04/25/science.1216567
