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Re: four winged Archaeopteryx

Mike is correct in all that he says, including his assumption that I was
referring to the more modern work.

Michael Habib wrote:

> > The supracoracoideus was experimentally disconnected in pigeons, but
> > they did NOT fly just fine.
> > This was an experiment done in Nazi-era Germany by Max-Heinz Sy (1936,
> > I believe).
> Actually, I think that Jim is referring to the more recent work.
> Degernes and Feduccia (2001) cut the tendon of the supracoracoideus
> muscle of pigeons and cockatiels, for example.
> They remark that "None of the birds undergoing unilateral or bilateral
> tenectomy had normal dorsal extension of the affected wing, but each
> was able to fly well enough to escape if taken outdoors. We concluded
> that neither unilateral nor bilateral supracoracoideus tenectomy is an
> effective technique for deflighting cockatiels or pigeons."
> I believe that have been some other recent studies with similar
> results.  Note as well that pigeons are something of an extreme case:
> they are largely burst launching species with a very large
> supracoracoideus.  So they stand to lose the most from such a
> tenectomy.  The same procedure in other species would probably have
> even less impact.
> >  If a bird or an airplane has to avoid flying in "slower speed
> > ranges", it can't take off.
> This turns out not to be the case, actually.  Plenty of modern birds
> must avoid slower speed ranges because they cannot avoid stall at low
> speeds.  They compensate in various ways, a running launch being one.
> Of course, it is quite unlikely that Archaeopteryx would even need
> that.  I suspect it could hit steady state from a leaping launch (like
> nearly all modern birds that are semi-terrestrial with low wing
> loadings).  Even if it could not get in especially rapid or powerful
> strokes, Archaeopteryx would have been able to get far enough to make
> such short flights of benefit for predator escape.  If it had any sort
> of elevated launch point, then it could get very far indeed, even
> without any flight stroke at all.
> We should also be careful assuming that the deltoids would be as
> ineffective in an early flying bird as in modern ones.  The deltoid is
> likely somewhat reduced in neornithines because the supracoracoideus
> has the dominant role in the upstroke (thereby making deltoid elevation
> largely redundant).  In earlier lineages, without an elevation
> supracora., it stands to reason that the deltoid could be more
> powerful, so we must not extrapolate too much (as tempting as that can
> be).
> Cheers,
> --MH