well, here is my living-mechanics wip:
cya henrik
p.s.: i need critism!
Cool 
Air bubbles following the diving bird looks more like smoke than air bubbles… If it is a halo change it to real dupliverted spheres with a transparent material with SpTr to maximum…
Stefano
well,they are dupliverted spheres 
but
I have to test that SpTr thingy…
here it is(far better, imho):
Thx, henrik