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RE: Sinocalliopteryx (Theropoda: Compsognathidae) ate confuciusornithids and dromaeosaurids

In Bird Flight (Facts on File 1990 New York) Robert Burton calls this Bounding 
Flight, distinct from the undulating flight seen in larger birds.

On page 97 he writes that it is seen in many small birds; warblers, tits, 
finches, wagtails, woodpeckers, finches, and small owls and parrots.

Hypothetically it saves energy. The bird coasts with wings folded, reducing 
drag, between bursts of propulsion. 

Birds don't do it when they are flushed or fleeing something, only in more 
casual times or heavy headwinds.

Dropping with folded wings from a perch, on the other hand, is documented in a 
beautiful (but small) photo on page 66, in a Little Owl.
From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] on behalf of dale mcinnes 
Sent: Sunday, September 02, 2012 2:45 AM
To: david.marjanovic@gmx.at; DML
Subject: RE: Sinocalliopteryx (Theropoda: Compsognathidae) ate 
confuciusornithids and dromaeosaurids

> Date: Sat, 1 Sep 2012 14:48:43 +0200
> From: david.marjanovic@gmx.at
> To: dinosaur@usc.edu
> Subject: Re: Sinocalliopteryx (Theropoda: Compsognathidae) ate 
> confuciusornithids and dromaeosaurids
> > On top of all this, I think there is an unconscious assumption in a
> > lot of discussions that the flight states are "stuck on the ground
> > like a turtle" vs. "as aerial as a sparrow or starling". But consider
> > that many modern birds do perfectly well with what from a sparrow's
> > point of view are extremely limited modes of flight: birds like
> > galliforms, for instance.
> I agree! Galliforms are bad examples, though: they are very _powerful_
> fliers. Basically all they do is lift off from the ground, lifting their
> wings way above shoulder height (famous criticism of WAIR).
> Sparrows are interesting in another way: they practice undulating
> flight. They fly with so much power that they don't need to sustain the
> effort. So, every other second, they just fold their wings and engage in
> free fall. Only passeriforms and piciforms (their sister-group) seem to
> do that, though.

David .. I've also seen corvids [magpies] do this as well. And they're not
particularly strong fliers .. rather clumsy I would say. I think birds do
this to pick up speed .. and just before they enter a canopy to land on a