I had a lot of trouble identifying what kind of bird this was, but I believe that it is an Anhinga that is drying. Their feathers are not waterproof like many birds that hunt fish underwater, so once it has finished hunting, it must come out and dry itself before it can fly well. Here is an Anhinga drying itself so it can take off after a hunt. I particularly like the reflection in the water of him. This is one of my favorite photos from Captiva.
Canon T3i, f5.6, 1/1000 sec, ISO – 1000, 300mm