Re: FUCHSIA and the Ostrom Symposium Volume (long...)

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Graydon" <graydon@dsl.ca>

> Forward stroke to downward stroke is an angle change; there's an obvious
> advantage to a cursorial predator in being able to apply the predatory
> stroke over a wider range of angles.  (Since you can adjust for dinner's
> desperate deeking better that way.)

Okay, but will the prey ever be directly under the predator, and if so,
won't the latter rather use its feet?

> If you're looking at _why_ a running animal would flap, well, presumably
> a cursorial predator needs to apply the predatory stroke _while it's
> running_.

I should have got that idea myself :-] -- but see below...

> That being the case, it really isn't a stretch to have the range of
> flapping behaviours expand; all it takes is some advantage -- in
> turning, or in traction, or in clearing an obstacle -- accrue to
> 'premature' use of the predatory stroke while outside of striking range
> in pursuit.

But all cursorial birds tend to fly as rarely as possible, or not at all,
arguing against the idea that flight is an advantage for a cursorial animal.
(This is Ebel's main argument against cursorial models.)

> Early use in turn can be explained by normal behaviour variation; some
> predators are more optimistic than other predators, and figure it's
> worth a try even when the odds are bad, and sometimes it helps balance
> to stick out a limb;

Agreed.

> either or both of those suffice to get onto that
> particular gradual ramp of moving toward the flight stroke from the
> predatory stroke.

But then... will they use the flight stroke?