From my recent quick-trip to Sanford FLA. I thought these birds were really fascinating as they would spread their wings and bask in the sun.
A little research informs me that this is an Anhinga (not a Comorant, my first guess)... And "Unlike most birds, does not produce oil to waterproof its feathers – which allows the bird to dive deep for prey but requires the bird to spread its wings to dry out after diving. "
Thanks Brian, Graeme, Walks & Haydn!!