Well, the Pisa shot is simply superb! Really very nicely done and comp'd perfectly (the colour match with the non CG building is spot on). I may be coming to you for some hints on bird animation very soon too - they're great!
As for the squirrel shot - it's good but there is something about it that doesn't quite work. I'm not quite sure if it's the actual motion of the squirrel or the compositing (though I gotta hand it to you - that must have been pretty tough to camera match!)
On the motion side of things, I think it's that they don't quite bound forward far enough and come down a little too quicky. It's quite tricky to see clearly but I think there is an odd shape to the tail and body posture just as the animal lands. It looks like the hind legs shoot forward and the tail springs out from a very nice 'C' shape on the previous frame to a very straight line on the next - which makes it look like the tail is whipping out and propelling the animal forward.
Hope you don't mind the crits
Btw, how is Crowd to work with? I've never tried it myself.