When they travel in packs, they are known as "a kettle of anhinga." Sometimes, when you look up, you can spot one simply gliding around on a thermal at high altitudes, barely flapping its wings, like a vulture or an eagle.
I suspect they have rich imaginative lives, the anhinga, going from sea-level to cruising altitude for their own mysterious purposes. I wonder if soaring is a relief for them, a break from the hard work of sinking into the water and chasing fish. I wonder if they compare which vasty blue space they like best: the one with air or the one with food?