Anhinga Field Guide — The Snakebird of Florida Wetlands

A bird that can’t fly wet hunts underwater by spearing fish with its beak like a thrown spear. That paradox — a committed swimmer that must dry its wings between dives — is the ecological signature of the anhinga, and once you understand it, every sighting makes sense: the motionless silhouette on a dead branch, wings spread wide into a crucifix pose, neck coiled back like a spring. Anhinga anhinga doesn’t do anything halfway. It is, from beak tip to tail fan, one of the most architecturally extreme birds in Florida.

It’s also one of the most commonly seen. Florida holds a dense, year-round resident population. Paddle any freshwater canal in the Everglades, walk the boardwalk at Wakodahatchee, or stop at any roadside pond between Naples and Gainesville, and you’ll find an anhinga within minutes — usually drying its wings in plain view, completely unperturbed by human presence.

ID at a Glance

Adult male:

• Size: Large waterbird, 85 cm (33 in) body length; wingspan approximately 117 cm. Long, fan-shaped tail is a constant field mark.
• Plumage: Glossy greenish-black overall. Wings and back show distinctive silvery-white streaks and oval spots — the clearest ID mark in good light.
• Bill: Long, straight, sharply pointed — a spear, not a hook. Yellow-orange at base, dark at tip.
• Neck: Extremely long and thin, held in an S-curve at rest and while swimming. The “snake” part of “snakebird.”
• Eye: Bright turquoise-green orbital ring (most vivid during breeding season).
• Lores: Bright yellow-orange bare skin during breeding.

Adult female:

• Same body size and wing patterning as male.
• Distinct buff-tan neck and breast — contrasts sharply with the dark body. The clearest sex-age field mark in Florida.
• Orbital ring less vivid than breeding male.

Juveniles:

• Like female: buff-tan neck and breast, less spotting on wings. Gradually acquire adult plumage over 1–2 years.

In flight: Long neck fully extended, long tail fanned, slow wingbeats alternating with glides. Often soars on thermals — surprising for a waterbird. The silhouette (long neck + long tail + broad wings) is distinctive and unlike any cormorant.

Similar species: Double-crested cormorant shares the wing-spreading behavior and dark plumage, but has a hooked bill, shorter tail, and lacks the white wing spotting. Neck shape is the fastest separator.

Taxonomy

Anhinga anhinga is one of four species in Family Anhingidae — the darters — placed within Order Suliformes alongside boobies, gannets, frigatebirds, and cormorants. Two subspecies are recognized: A. a. anhinga (North, Central, and northern South America) and A. a. leucogaster (southern South America), differentiated by minor plumage details. The three Old World darter species (Anhinga rufa, A. melanogaster, A. novaehollandiae) occupy Africa, Asia, and Australia respectively, reflecting the family’s Gondwanan origins.

The name “anhinga” derives from the Tupi language of Brazil (anhangá, a term for an evil spirit or devil bird). The “snakebird” nickname, used across the range from Florida to Argentina, describes the swimming posture — only the long neck and small head visible above the water surface, the body submerged, looking precisely like a swimming snake.

Range and Habitat in Florida

Anhinga anhinga is a year-round resident throughout peninsular Florida and the panhandle, with the densest populations in the freshwater wetlands of south-central Florida. The species is absent only from the most exposed coastal environments — pure saltwater and open ocean are not its habitat.

Core habitat: Slow-moving freshwater — cypress swamps, freshwater marshes, vegetated lake margins, sluggish canals, and the interior of mangrove-freshwater ecotones. The anhinga needs clear or moderately clear shallow water (for underwater visibility while hunting), emergent or overhanging woody vegetation (for perching, wing-drying, and nesting), and sun exposure.

Key Florida locations: Everglades National Park (Anhinga Trail at Royal Palm is the most famous single location in the world for close encounters), Big Cypress National Preserve, Corkscrew Swamp Sanctuary (Collier County), Wakodahatchee Wetlands (Palm Beach County), Green Cay Wetlands (Palm Beach County), Myakka River State Park (Sarasota County), Lake Apopka (Orange/Lake counties), Silver Springs State Park (Marion County), and the Ocala National Forest lakes.

Seasonal dynamics: Florida’s resident population is augmented in winter (October–March) by birds from northern breeding populations in Georgia, South Carolina, and Alabama that winter in the Florida peninsula. Summer (April–August) is nesting season — colonies become highly visible.

Behavior and Ecology

Foraging: Anhinga anhinga is an underwater pursuit predator. Unlike herons (which stand and strike from above) or ospreys (which dive from the air), the anhinga enters the water from a perch or while swimming, submerges completely, and chases fish underwater using its powerful feet and partially folded wings for propulsion. The final strike is delivered with a rapid spear thrust of the bill — the neck straightens explosively in a muscular movement driven by a specialized hinge mechanism between the 8th and 9th cervical vertebrae. Fish are impaled, brought to the surface, tossed into the air, and swallowed head-first.

Prey: Primarily fish 2–15 cm in length — bluegill, bass, perch, catfish, and other freshwater species. Occasionally takes frogs, aquatic invertebrates, and small water snakes.

The wet-wing paradox: The anhinga’s feathers lack the preen-oil waterproofing of most waterbirds. Water penetrates to the skin, reducing the bird’s buoyancy — which is adaptive for underwater hunting, as it doesn’t need to fight against a built-in flotation device. The tradeoff is that it must dry its wings before it can fly. Wing-spreading drying sessions last 5 minutes to over an hour, depending on temperature, wind, and sun angle. On cold or overcast days, anhingas can be grounded for extended periods after diving.

Nesting: Colonial breeder, typically nesting in mixed colonies with herons, egrets, cormorants, and roseate spoonbills in dense cypress or mangrove stands. Stick platform nests are placed 2–10 meters above water. Both parents incubate 3–5 eggs for approximately 28 days. Chicks are altricial (helpless at hatch) and are brooded for several weeks. The nesting season in Florida runs approximately February–June.

Soaring: Despite the wet-wing limitation, anhingas are capable and frequent soaring birds when their plumage is dry. They ride thermals to significant altitudes — a behavior unusual among waterbirds — and are sometimes mistaken for raptors at distance. Migration (partial, in the northern part of the range) is accomplished via soaring.

Conservation Status

IUCN: Least Concern (LC). Population trend is stable, and the species has a broad range from the southeastern United States through Central America and tropical South America to Argentina.

US protections: Federally protected under the Migratory Bird Treaty Act. No special state-level threatened or endangered status in Florida.

Florida population: Stable to increasing. The Florida breeding population benefits from the same suite of freshwater wetland protections that support herons, egrets, wood storks, and other wading birds. The Everglades Restoration program (CERP), if successful in restoring more natural hydropatterns, is expected to benefit anhingas by increasing fish productivity in the interior wetland system.

Key threats: Wetland drainage and degradation (historical and ongoing), water quality degradation in freshwater systems, nest disturbance at colonial breeding sites, entanglement in monofilament fishing line (documented at managed wetland sites). Mercury bioaccumulation through fish is an ongoing concern in south Florida systems.

Where to See It

Anhinga Trail, Royal Palm, Everglades NP: The premier close-encounter site in the world. A short (0.8-mile) loop boardwalk passes directly alongside Taylor Slough, where anhingas nest, hunt, and dry their wings at arm’s length from the trail. Best in winter dry season (November–April) when fish concentrate in the slough. Some of the most photographed individual birds in Florida ornithology have nested here for decades.

Wakodahatchee Wetlands, Delray Beach: A 3/4-mile boardwalk over constructed freshwater wetlands with nesting platforms. Anhingas are visible year-round, nesting in spring. Exceptionally accessible and reliable.

Green Cay Wetlands, Boynton Beach: Similar boardwalk format to Wakodahatchee, 10 miles north. Both sites are free and open daily.

Corkscrew Swamp Sanctuary: The 2.5-mile boardwalk through old-growth bald cypress hosts nesting anhingas; spring through summer is most active.

Myakka River State Park, Sarasota County: The two large lakes hold anhingas year-round. Boat tours on the upper lake provide close views.

Timing: Year-round in Florida. Most conspicuous during nesting season (February–June) when colonies are active. Winter (November–March) brings additional birds from the north.

Interesting Facts

• The anhinga’s name traces to the Tupi word for “devil bird” or “evil spirit” — likely inspired by its eerie, silent swimming posture, only the thin neck visible above the water.
• Anhinga anhinga can dive to approximately 60 cm (2 feet) and remain submerged for up to a minute during active pursuit of fish.
• The specialized vertebral hinge that powers the spearing strike is a convergent evolution — a nearly identical mechanism evolved independently in herons, though the two lineages are only distantly related.
• Anhingas are one of very few birds that regularly soar on thermals alongside raptors and vultures, a behavior most visible on warm mornings in Florida as birds dry off and gain altitude for travel or foraging site selection.