Anhingas are Fascinating Water Birds
by Ro Wauer
A recent trip with friends to one of the side-streams for Colleto Creek Reservoir reminded me once again about the oddity of anhingas. We watched one individual swimming about, barely below the surface, while another individual, finished fishing for the time being, perching on a snag over the water, sat spread-winged to dry its feathers. The anhinga is one of only a few water birds that must air-dry its feathers after a swim. It lacks adequate oil glands to keep its feathers dry. So rather than preening before and after a swim, an anhinga must sit with its wings spread, like vultures do to warm their body on a sunny morning, to dry its plumage. It even alternately turns its wings to expose both upper and lower surfaces.
Anhingas possess an extremely long neck and bill. Their posture when sitting is very snake-like, a profile that has provided them with the "snakebird" name. Even when swimming, they often extend their neck high above the water, very snake-like. Its posture and behavior has also provided the name "darter." And they also are sometimes known as "water turkey." This name was derived from the unique structure of tiny ridges that cross their tails, turkey-like, that is most evident when perched.
The perched Colleto Creek anhinga was uttering strange grunting sounds, like deep clicking. It was obviously nervous, probably from being examined by three humanoids, even from a distance. It actually waved its neck about, and eventually dropped into the water and immediately dove out of sight. But it didn't swim far before breaking the surface and taking off with what seemed like considerable effort before it became air-borne. But once in flight it was fast and graceful.
We found several anhingas when we began to scope the area; a couple in the water and another half-dozen individuals perched on adjacent vegetation. The perched birds apparently had already dried their plumage, as they sat still with wings folded, but with their long snake-like neck sticking up high in the air. None of the perched birds appeared to be youngsters, although anhingas undoubtedly do nest in the area. They normally construct stick-nests at mid-height on woody vegetation surrounding ponds or bays. They much prefer fresh-water areas. A colonial nester, they may congregate at choice nesting sites by a dozen or more. Males choose the nest site and do most of the nest building. Although the nest is little more than a bulky platform of sticks, twigs, and dead leaves, it is lined with green leaves and finer materials. Anhingas will occasionally appropriate a heron or egret nest. Courting males perform spiral aerial displays for their ladies, and perched males also perform wing-waving displays and reverse bows by raising their tail and bringing their long neck back to touch their back.
The anhinga diet is predominately fish that is captured just below the surface of the water. They also will feed on various other aquatic prey. They have been known to take goldfish in outdoor ponds, and will prey on various insects as well as crayfish, frogs, snakes, and even young alligators. Unlike their closely related cormorant cousins that swims down their prey, anhingas typically wait for a passing fish. They are then able to spear their prey with amazing speed and dexterity with their long, pointed bill. The impaled prey is then brought to the surface where it usually is tossed into the air and swallowed head first. When feeding young, the adults will regurgitate their food into the wide-open mouth of the nestling.
There is no doubt those anhingas, whether they are known as anhingas, snakebirds, darters, or water turkeys, are fascinating bird. A visit to one of our local freshwater ponds will likely provide a look at this marvelous creature.