We have done a fair number of river tours, harbor tours and birding tours. This is among the best.
Gary, the owner, was our captain and guide. My wife and I are novice birders and we thought we were good at picking out the wildlife we see, but Gary routinely saw things before we did and we were using binoculars.
The only "rare" species was saw was the purple gallanoule, but the ability to get so close to so many other birds was amazing. We saw several hundred white ibis roosting in the trees along the route. We saw the usual compliment of coots, great blue herons (some nesting early this year), great egrets, cattle egrets, mature and immature little blue herons, kingfishers, and hawks. Not bad for a two hour cruise on the river.
As the picture shows, this is a pontoon boat. It is not an airboat. This is a good thing. I know that in many areas airboats are preferred because they are faster and can go into shallower water than a pontoon boat can, but a pontoon boat is quiet and does not scare away half of what you came out to see. Environmentalists hate airboats and love pontoon boats.
The fine print: (There is always fine print.) Birds are the originators of the expression "fly by night" and that is what they do. They're here today and gone tomorrow. So, just because I saw a thousand ibis today that does not mean that you will. In fact, after seeing hundreds of birds together, we turned a corner on the river and there were none. However, even in summer when the birds are mostly up north (They are "snowbirds" after all.), the lush greens of the plant life and the reflections on the dark water should be spectacular.
The drive from the attractions area is over an hour, but is worth the trip.