They know what they're doing.  I love watching birds move from a chaotic dog pile in the sky to this ordered division of labor that is not only functional but also decorative.  While the cormorants are a work of art in action, I have to say I prefer the pelicans.  They line up for a while and then a bird will decide, heck, maybe not, and off he veers, and then another pelly will go a different way and then there's two off to gate-crash the party of fisherman trying to earn his bread and butter and then they're back together again, even if they're not the same birds in line.  They make it work, they work it, and then again, whatever.  This is where evolution will take us if we can stick it here as long as these guys have.