Anhingas, One of Our Strangest Waterbirds
by Ro Wauer
My house is about five miles from the Guadalupe River and the scattered associated ponds. So it was a surprise to see one of these waterbirds, like a dark cross, soaring high over my yard instead of flying along the river or sitting on a snag along the waterway or a pond. It was yard bird number 177 for my growing list of bird species seen within or from my yard. That list is not growing as fast as it was a few years ago, with only the Eurasian collared-dove being added in 2005. But a soaring anhinga is fairly easy to identify because of its long neck and long, pointed bill, and long but rounded tail.
Anhingas in their more typical water environment usually are found in the water or sitting on a post or tree limb. Those found in the water often are initially misidentified as some snake-like creature because only their long neck and head may be seen, curved in a serpentine S, above the surface. It is able to cut back on the stored air so that its buoyancy declines, allowing it to sink so that its body disappears, with only its head and long, slender neck showing. Thus, one of its many names is snakebird.
More commonly, anhingas usually are found perched along the waterside, either sitting quietly with folded wings or with wings spread. The later poise usually occurs right after they have emerged from the water, and their spread-wing position allows their plumage to dry. But their spread-wing position is mostly for thermoregulation, to absorb solar energy to supplement their low metabolic heat production, after a swim. And unlike other birds that perch with spread wings, such as turkey vultures, anhingas will often sunbath facing the sun. They also are known as "water turkeys," because of their relationship to water and the unique structure of tiny cross ridges on their tail, like that of turkeys.
Still another name for the anhinga is "darter," after their characteristic feeding behavior of spearing prey underwater with their long, sharply pointed bill. They will then awkwardly fly or crawl onto a nearby perch with their prey where they then will flip the fish or other prey into the air and catch it headfirst to swallow it whole. At times, when the prey is too large to swallow whole, it will pound its prey again a perch or fly to a rocky shore and pound it into pieces. Although fish are its principal prey, anhingas are known to take a wide assortment of water creatures, including snakes, frogs, turtles, and even baby alligators.
Anhingas are members of a unique family of birds, known as Anhingadae, although this family of darters occurs worldwide. The anhinga name stems from a language of the Amazonian Indians. In North America, its breeding range extends primarily along the Gulf Coast and northward along some of the southern rivers. But there are a number of records further north, particularly after nesting. The more northern nesters migrate south in October and return in late February or March. But a few anhingas can usually be found in South Texas year-round.
Where can one expect to see one of these fascinating birds? Although they are possible along any of our slow-flowing waterways or at both small and large ponds, I have had excellent observations at cove-like sites along Coleto Creek Reservoir and at Guadalupe Delta Wildlife Management Area along US Highway 35. Good luck!