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Respect for corvids.



Carrying the flag for archosaur cooperation--and therefore possible
breaking the bracket of noncooperation!--ravens may indeed practice more
advanced forms of cooperation than assumed possible for birds.  Heinrich 
(Bernd Heinrich  1989 _Ravens in Winter_) reports a number of anecdotes
which ought to suggest a closer look.  He also spent a long time
documenting a cooperative behavior, that of recruiting other ravens to a
large carcass.

He goes through a large number of hypotheses for this altruistic behavior
and favors these: a) juveniles en masse can drive off resident dominant
birds.  So they call in vagrants for miles around to overwhelm them; b)
actively courting juveniles are displaying their abilities to both attract
mates and bring themselves up in the world.

This seems to me very similar to an earlier example I gave of macaques
spread out in a forest to find fruit trees and then calling out.

Indeed, enhanced status may be a prime "reason" for so called reciprocal
altruism in humans.  Dominance hierarchies, if they existed, may have
provided a substrate upon which cooperation may have evolved in dinosaurs.

Therefore, while there is no evidence to suggest dinosaurs did cooperate,
speculation along these lines has some support.

I realize that cooperative foraging is not cooperative "pack hunting".
But again, if it is possible in one foraging style I don't see a reason
for _a priori_ dismissal in another (not that anyone here is doing any _a
priori_ dismissing).