A UV will protect his lens, which isn't a bad idea if he is getting up close and personal with some of the beasts. Also a CP would be good... but to be honest I never use either anymore :shrug:
the cir-pl might be useful if the cages have a glass front and are outside... it might help cut down on reflections...
If your shooting through a glass window though.. i find it helps if you hold the end of the lens flat up against the glass. This should help cut down on light spots in the photo..
