RE: Life of Birds (vertical running)

["R. Irmis" <rbi@dana.ucc.nau.edu>]

<<I am going to state publically that I now agree that Greg Paul et al. are
almost certainly correct in the following aspect: the broad feathers and the
forelimb adapations of dromaeosaurids, troodontids, and oviraptorosaurs are
almost certainly associated with an avian style form of locomotion.
However, to qualify that: that locomotion is almost certainly NOT flight,
and I don't think there is any secondary loss involved: I strongly suspect
that young members and small adult individuals of these taxa practiced this
locomotion.>>

For dromaeosaurs and troodontids the applications are obvious.  For larger
animals that are attacking prey with the modified pes, this type of
locomotion would help keep the individual against the prey while
running/jumping on to it.  For smaller members of these clades and
juveniles, the hyperextendable digit could act as a grappling hook to help
get up a vertical surface in conjunction with this locomotion to get away
from predators, etc.

Just some speculation for you...

Regards,
Randall Irmis