> Fault barring is an interesting phenomenon also mentioned by Stuart. Fault
> bars, or growth bars, are actually thought to represent daytime and
> nighttime growth, which probably happen at different rates and thus cause
> the bars; thus each pair of bars represents one day's growth. ...

I have read something like this concerning at least the Blue Tit _Parus
caeruleus_ (and actually saw these bars very well on dead tits).
However, as far as I can recall, I thought the bars were "daily" only in small
birds.

> ... This is still an untested hypothesis.

As I just said, I think it has been tested in Europe (I guess in England).
I will try to find out some references when going back to France.

--
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A bird in the bush is better than two in the hand.

Serge Le Huitouze Intelligent Software Group
email: serge at cs.sfu.ca School of Computing Science
tel: (604) 291-5423 Simon Fraser University
fax: (604) 291-3045 Burnaby, B.C., V5A 1S6 CANADA