Anhinga

Quick Facts

Migratory

• Scientific Name: Anhinga anhinga
• Spanish Name: Pato aguja
• Family: Anhingidae
• Known Nicknames: Snakebird, Water Turkey, American Anhinga, Darter
• Average Length: 75–95 cm / 29.5–37.4 in
• Average Weight: 1.04–1.35 kg / 2.3–3.0 lb
• Wingspan: 109 cm / 43 in
• Key Feature: Elongated S-shaped neck and sharp, dagger-like bill; often swims with only the head and neck visible above water
• Primary Diet: Primarily Piscivore (Fish)
• Range: Southeastern United States through Mexico and Central America to Northern Argentina and Uruguay
• Habitat: Shallow, slow-moving or still freshwater environments including swamps, lakes, and marshes
• Social Structure: Semi-social; frequently nests in colonies alongside herons, egrets, and cormorants
• Nesting/Breeding: Bulky platform nests of sticks and green leaves built in trees or bushes overhanging water
• Statut de conservation : Préoccupation mineure (LC)
• Population Trend: Stable

The Anhinga, often referred to as the "Snakebird" or "Water Turkey," is a striking water bird of southern marshes characterized by its slender, S-shaped neck and long, fan-like tail. Unlike most aquatic birds, the Anhinga lacks uropygial oil glands to waterproof its feathers; while this makes its plumage heavy and waterlogged, it provides a unique predatory advantage by allowing the bird to lose buoyancy and dive deeply to spear fish with its dagger-like bill. Because of this lack of waterproofing, the Anhinga is frequently seen in a dramatic, heraldic pose, perching with its silver-streaked wings spread wide to dry in the sun and regulate its body temperature. Whether it is swimming with only its head and neck visible above the surface—mimicking a serpent—or soaring on thermal updrafts, this master of the wetlands is a fascinating example of specialized evolutionary adaptation.

Faits amusants

Often nicknamed the "snake bird," this avian predator swims with its body fully submerged, leaving only its sinuous neck visible above the surface. Because they lack the oil glands typical of other waterbirds, their feathers become waterlogged; while this reduces buoyancy for more efficient diving, it requires them to spend hours perched with wings outstretched to dry in the sun. Instead of grasping prey, they use their serrated, needle-sharp bills to spear fish underwater, often surfacing to toss their catch into the air and swallow it head-first. Remarkably, they have no external nostrils and breathe entirely through their mouths, an adaptation that prevents water from entering their airways during deep dives.

Habitats et répartition

This species thrives in shallow, still, or slow-moving freshwater environments, including cypress swamps, marshes, lakes, and sluggish rivers. It requires habitats with ample vegetation and accessible perches, such as partially submerged logs or overhanging branches, which are essential for drying its plumage after foraging underwater. While predominantly a freshwater inhabitant, it is also frequently observed in brackish coastal lagoons and mangrove-lined estuaries. The geographical range spans the warmer regions of the Americas, extending from the southeastern United States through Mexico and Central America into South America. In the U.S., it is commonly found from North Carolina south to Florida and west into Texas. Further south, its distribution covers much of the South American continent, reaching as far as northern Argentina and Uruguay. Most populations are permanent residents, though those at the northernmost fringes of the range may migrate south during the winter to avoid freezing temperatures.

Comportements & Reproduction

Often observed in a spread-wing posture to dry their non-waterproof plumage, these birds are primarily solitary but aggregate into colonies during the breeding season. Their social structure shifts from independent hunters to colonial nesters, often sharing space with herons and egrets. Mating begins with elaborate courtship displays where males perform soaring flights and ritualized movements, such as waving wings or presenting nesting material to prospective females. Once paired, they exhibit monogamous behavior for the duration of the season, collaborating closely on territory defense and nest construction. Reproduction involves the communal effort of both parents, who build a platform nest of sticks and green vegetation typically located in trees overhanging water. The female lays a clutch of two to five eggs, which both adults take turns incubating for approximately four weeks. A unique aspect of their parental care is the shared responsibility for feeding the altricial chicks; both parents regurgitate partially digested fish directly into the throats of the young. This biparental investment continues until the fledglings are capable of hunting independently, ensuring higher survival rates in their aquatic habitats.

Alimentation

The Anhinga is primarily a piscivore, focusing its diet on a variety of small to medium-sized fish, though it also opportunistically consumes crustaceans, amphibians, and aquatic insects. Unlike many diving birds that grasp their prey, the Anhinga uses its long, slender, and sharply pointed beak to spear fish with a rapid, snake-like thrust while submerged. Because its feathers are not fully waterproof, the bird loses buoyancy and can swim stealthily underwater to stalk its targets with minimal effort. Once a fish is impaled, the Anhinga returns to the surface, shakes the prey off its bill, and expertly tosses it into the air to swallow it headfirst, a technique that prevents the fish's fins and spines from catching in its throat.

Couleurs

Adult males feature a glossy black-green body accented by dramatic silvery-white streaks and spots on their wings and upper back, while females and juveniles are distinguished by a pale tan or buff-colored neck and breast. Both sexes possess a long, pointed yellow bill and a fan-shaped tail frequently tipped with white or buff. Their dark plumage serves as effective camouflage in murky waters, where their slender, submerged profile often mimics a snake.

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