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Re: FW: The ground-nowhere hypothesis on the origin of bird flight (joke)



The birds you mention do not pounce from a tree.

They sit in an elevated position, on the lookout.
The tree serves as a lookout tower, from which they can see prey easier.
Once they spot the prey, they go chase after it.
In a humans case, once the prey is spotted, a projectile is launched at it.
Raptors sitting in a tree will attack prey much farther away than what they 
could get to by gliding (especially if that glide has to be fast to catch the 
prey unaware/in time).
Like a human in a tree, a raptor sitting in a tree has a huge hunting area.
Some primitive glider incapable of powered flight sitting in a tree would have 
a tiny hunting area.
Several orders of magnitude less in fact.
At half the "predation radius" (the radius from the perch at which prey can be 
hunted from the perch), the hunting area is reduced to 1/4.

The early "bird's" glide ratio was clearly less than half that of a 
hawk/eagle/buzzard, and the inability to undergo powered flight (since we are 
hypothesizing a precursor to powered flight), lead me to guess the radius from 
the perch it could go after prey is less than 1/4 that of the radius for a 
raptor.

Thus their hunting area would be less than 1/16th that of modern raptors, and 
we can't conclude that because its a viable strategy for modern raptors, that 
it was a viable transition form.

--- On Mon, 10/12/09, dale mcinnes <wdm1949@hotmail.com> wrote:

> From: dale mcinnes <wdm1949@hotmail.com>
> Subject: FW: The ground-nowhere hypothesis on the origin of bird flight (joke)
> To: "DML" <dinosaur@usc.edu>
> Date: Monday, October 12, 2009, 9:21 AM
> 
>  <140054.33837.qm@web50812.mail.re2.yahoo.com>
> Content-Type: text/plain; charset="iso-8859-1"
> Content-Transfer-Encoding: quoted-printable
> MIME-Version: 1.0
> 
> 
> Whooooa.
> =20
> Mammals need to eat way too often to be able to just sit in
> a tree=20
> and wait for something to walk underneath them? Really??
> This may
> not be the preferred method of mammals but they can do it.
> They
> don't just pick any old tree. They pick a tree tha
 in=2C drag food up=2C and in the
> case of=20
> hunting=2C pick a nice shady spot around a waterhole and
> wait. Yes.
> Wait. All day if necessary. If not longer. Burns fewer
> calories.=20
> Much fewer calories. And meat is reasonably assured here.
> =20
> But raptors do this. Especially eagles. Hunting fish.
> Hunting birds.
> Hunting mammals. Doesn't matter. It probably all leads back
> to that
> proavis hunting strategy around a water hole. Think Archie.
> Am I
> close here? --dale
> 
> 
> ----------------------------------------
> > Date: Mon=2C 12 Oct 2009 07:29:29 -0700
> > From: d_ohmes@yahoo.com
> > To: dinosaur@usc.edu
> > Subject: Re: FW: The ground-nowhere hypothesis on the
> origin of bird flig=
> ht (joke)
> >
> > Hmmm. Perhaps the drop-bear is attracted to camera
> straps?
> >
> > More seriously -- mammals need to eat way too often to
> be able to just si=
> t in a tree and wait for something to happen to walk
> underneath them. There=
>  is another factor too=3B most prey is alert enough that
> missing your initi=
> al pounce is likely=2C and if a prey species are slow
> movers=2C then active=
> ly searching works better than waiting anyway. All in
> all=2C I think pounci=
> ng is highly over-rated=2C at least in today's world.
> >
> > The local anoles seem to use it w/ success on
> insects=2C though=2C so I t=
> hink it still plays in flight evolution cartoons.
> >
> > Humans hunt deer from trees of course=2C w/ good
> success=2C but use proje=
> ctile weapons to greatly increase their killing range as
> well as various ba=
> its=2C scents=2C and calls. I once calculated the cost of
> licensing=2C spec=
> ial clothes=2C weapons=2C trucks=2C refrigeration and other
> accessories and=
>  came up w/ a total cost 250$US/lb for venison (although
> assuming 2 deer/ye=
> ar for 10 years=2C and 10 years per truck it gets closer to
> 15$US).
> >
> > --- On Mon=2C 10/12/09=2C Tim Williams wrote:
> >
> >> From: Tim Williams=20
> >> Subject: Re: FW: The ground-nowhere hypothesis on
> the origin of bird fli=
r 12=2C 2009=2C 12:11 AM
> >>
> >>
> >> Dann Pigdon=20
> >> wrote:
> >>
> >>
> >>> I've seen lots of leopard hunting footage over
> the
> >> years=2C
> >>> but I've never seen a leopard leap onto
> >>> prey from above.
> >>
> >>
> >> I'm sure there are other examples=2C but the only
> mammal I
> >> can think of that leaps out trees to attack prey
> on the
> >> ground is the drop-bear of Australia. British and
> >> Japanese tourists are its preferred prey.
> >>
> >> http://en.wikipedia.org/wiki/Drop_bear
> >>
> >>
> >>
> >>
> >> Cheers
> >>
> >> Tim
> >>
> >>
> >>
> >>    
>         
>           
>   =0A=
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