Jose wrote in news:AXvTg.18304$Ij.6358
@newssvr14.news.prodigy.com:

Almost thirty years ago I went to school with a chap who discovered
magnetite in the brains of birds, and speculated that it was used in
navigation. He did a lot of research on it (I think it was his thesis).
I haven't followed the research closely, but I think he pretty much
established it.

According to wikipedia, as well as http://www.affs.org/html/biomagnetism.html
the Academy for Future Science, magnetite is also found in human brains. But
I can't tell which way is North without a compass either...

The AFFS site seems to indicate that the magnetite in the brain is used to
generate the "natural" electricity that is found throughout the nervous and
muscular system. It even mentions the skeletal structure as being
conductive...

My guess is that birds use it for the same thing...