ehh... save your gas money.
The animals are all lonely-looking and there is a lot of concrete. I guess that they may have bee doing some maintenence or something, because most of the exhibits had all the water drained out of the animals living area. looked kinda crappy- but I sure it looks better with the water in there. It was friggin hot too, so most of the animals were tucked in a corner of their area either sleeping or staying cool.
It makes a nice side trip if you are already in Birmingham, but I would not drive all the way over there to see it.