Large aquatic birds, the anhinga and the double-crested cormorant (Florida cormorant, subspecies) are regularly misidentified. They are approximately the same size and color.
The male anhinga is black with silvery wing patches; the female differs with a tan head, neck and upper chest. The cormorant also displays dark plumage with a yellow-orange throat patch and double crests during the mating season — a similar pair.
Yet, the most captivating feature of these birds is the sunning posture. Drying on a branch, they are impressive with kinked necks, wings outstretched and backs to the sun. Ostensibly, they need to warm up or dry their feathers to fly since they emerge waterlogged from diving and swimming underwater. However, this lack of waterproofing (no proper oil glands) enables them to stay submerged to capture fish, their primary food.
Indeed, research differs. An expert maintains that the anhinga possesses the uropygial (oil) gland and is quite water resistant. Seemingly, it needs to sun for thermoregulation (sometimes for comfort) since it does not have an insulating layer of feathers like the cormorant.
Obviously, the cormorant withstands colder climates, and recent studies insist it emerges dry after deep dives, due to preening oil and microstructure of feathers. Conceivably, it simply savors the sun as do humans.
Reduced buoyancy, possibly due to wet plumage, dense bones or letting air out of air sacs allows the anhinga to swim with only its longer, thinner, snakelike neck and head exposed — sometimes just the long, pointed bill protrudes. Accordingly, it is called the snakebird. The cormorant swims comparably and exhibits a distinctive bill — long and hooked.
With a lengthy, fan-like tail, the anhinga is also identified as the water turkey. The cormorant’s tail, often used as a perching prop, is stiff and short. Formerly, the cormorant gained recognition as a hood ornament for the defunct Packard automobile.
For both, diving is expertly accomplished. After plunging from the surface, the cormorant might penetrate 60-feet deep, emerging in about a minute. The anhinga smoothly enters the water and remains submerged for a substantial period.
Webbed feet propel these birds underwater. The anhinga stalks slow-moving fish. It thrusts its bill and spears the side of the fish, surfaces and spectacularly flips and consumes it headfirst. The cormorant, a more powerful swimmer, is able to grasp faster fish with its hooked bill. Emerged, it also adeptly manipulates its prey.
In some Asian cultures, the ancient practice of employing certain species of cormorants to fish is ongoing. The leg is tethered and a soft neck noose restricts the bird from swallowing larger fish.
The negative impact of the double-crested cormorant on fisheries or catfish farms requires control. Unfortunately, it also kills trees and vegetation with guano.
Florida provides appropriate habitats. The anhinga prefers freshwater environments, and the cormorant also seeks saltwater coastal areas — these birds are adaptable. They may feed and roost close together. Both breed in colonies, commonly in trees near water, and sometimes among other waterbirds.
Unquestionably, the Everglades National Park offers a unique habitat. Along the Anhinga Trail, the anhinga glides from a tree to commence flight or runs on water when wet, vigorously flapping to become airborne and glide high. The cormorant, a less agile flier because of diving adaptation, may sloppily "hop" across the water to begin flight; it flies low, rapidly pumping its wings.
Most alluring are these birds’ spread-winged silhouettes against the orange sunset. They also entertain at the Viera Wetlands!