Thoroughly adapted for life in the water, the Anhinga’s bones are denser than those of most other birds, and their feathers can absorb water, meaning that they have an easier time staying underwater when foraging for fish. Having absorbent feathers also means that Anhingas spend time sunning themselves on branches so their feather can dry and they can warm up after swimming.
Anhingas propel themselves underwater with their feet. They are not particularly fast swimmers, and usually catch their prey by stalking it rather than chasing it. In flight, Anhingas often use rising thermals for soaring, and can sometimes be seen this way in large groups overhead.
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Description of the Anhinga
The Anhinga is largely a glossy, greenish-black bird with silvery streaking and spotting on its wings and back. It has a long tail, a long, snakelike neck, and a long, dagger-like bill. Dark head and neck with short, whitish plumes. Length 30-38 in. Wingspan: 44 in.
Brownish head and neck.
Seasonal change in appearance
Males lose white head and neck plumes in the winter.
Similar to adult females, but duller.
Swamps, rivers and ponds.
Forages underwater by diving or head-plunging while swimming.
Anhingas breed widely in the southeastern U.S. and farther south to South America. Population stable.
Bent Life History
Visit the Bent Life History for extensive additional information on the Anhinga.
The vertebrae in the Anhinga’s neck are structured in such a way as to allow the powerful stabs needed to spear fish with their sharp bill.
Young Anhingas can swim before they can fly, and will jump in the water to avoid danger.
An occasional clicking or chattering noise is made at the nest.
Double-crested Cormorants have less pointed bills and thicker necks.
The Anhinga builds a platform of sticks in a tree, usually over water.
Color: White or bluish.
Incubation and fledging:
– Young hatch at about 25-29 days.
– Young fledge (leave the nest) in 14-21 days, but associate with the adults for some time.
Bent Life History of the Anhinga
Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.
Bent Life History for the Anhinga – the common name and sub-species reflect the nomenclature in use at the time the description was written.
ANHINGA ANHINGA (Linnaeus)
In the swamps and marshy lakes of Florida, where the shores are overgrown with rank vegetation and the stately cypress trees are draped with long festoons of Spanish moss, or in the sluggish streams, half choked with water hyacinths, “bonnets” and “water lettuce,” where the deadly mocassin lurks concealed in the dense vegetation, where the gayly colored purple gallinules patter over the lily pads and where the beautiful snowy herons and many others of their tribe flourish in their native solitudes, there may we look for these curious birds. We may expect to find them sitting quietly, in little groups, in the tops of some clump of willows on the marshy shore or on the branches of some larger trees overhanging the water, with their long necks stretched upwards in an attitude of inquiry or held in graceful curves if not alarmed; perhaps some may have their wings outstretched in the sun to dry, a favorite basking attitude. If alarmed by the sudden appearance of a boat one may be seen to plunge headlong into the water, straight as a winged arrow, and disappear; soon, however, a snake-like head and neck may be seen at a distance rapidly swimming away with its body entirely submerged. The anhinga is a water bird surely enough, but I could never see any resemblance to a turkey, and I can not understand how this name happened to be applied to it. The name “darter” or “snake bird,” both of which are descriptive, seem much more appropriate.
Spring: Throughout the southern portion of its range, in the Gulf States and in tropical America, the water-turkey is a resident throughout the year, but it migrates a short distance northward, up the Mississippi Valley and to the Carolinas, in March, avoiding the salt water and frequenting the inland marshes and ponds.
Courtship: Audubon (1840) observes that during its courtship the movements of its head and neck: Resemble sudden jerkings of the parts to their full extent, become extremely graceful during the love season, when they are reduced to gentle curvatures. I must not forget to say that during all these movements the gular pouch is distended, and the bird emits rough guttural sounds. If they are courting on wing, however, in the manner of cormorants, hawks, and many other birds, they emit a whistling note, somewhat resembling that of some of our rapacious birds, and which may be expressed by the syllables cek, eek, eek, the first loudest, and the rest diminishing In strength. When they are on the water, their callnotes so much resemble the rough grunting cries of the Florida cormorant that I have often mistaken them for the latter.
Nesting: My first experience with the nesting habits of the water-turkey was in the extensive marshes bordering the upper St. Johns River in Florida. The river at this point is spread out over a marshy area about 3 miles wide with a narrow open channel and a series of small lakes or ponds in the center. Except in these open places the water is very shallow, from 1 to 3 feet deep, with a treacherous muddy bottom, making wading impossible. The marsh consists of broad areas of saw grass among which are numerous tortuous channels overgrown with a rank growth of coarse yellow pond lilies, locally known as “bonnets,” through which we had to navigate by laboriously polling a shallow, pointed skiff. The channels are still further choked by small floating islands, made up of bushes and rank aquatic vegetation, which drift about more or less with the changes of the wind. There are also many permanent islands overgrown with willows, which serve as rookeries for thousands of Louisiana herons, little blue herons, anhingas, and a few snowy, black-crowned and yellow-crowned night herons. Least bitterns, red-winged blackbirds, and boat-tailed grackles nest in the saw grass; coots, purple and Florida gallinules frequent the “bonnets,” and large flocks of white ibises, wood ibises, cormorants, and a few glossy ibises fly back and forth over the marshes, especially at morning and evening.
Here we found, on April 18 and 21, 1902, several small breeding colonies of water-turkeys in small isolated clumps of willows or on the borders of the larger willow islands inhabited by the various herons. There were never more than 8 or 10 nests in a group, which were placed from 5 to 15 feet above the ground or water and were very conspicuous; we generally saw the anhingas sitting in the treetops and sometimes saw them on their nests as we approached. The nests were easily recognized, as they were always lodsely built, often quite bulky and irregular in shape and always showed a large quantity of brown, dead leaves mixed with the sticks in the body of the nest. The nests were generally carelessly built, mostly of willow twigs and coarse sticks, mixed with the dead leaves, which gave them a ragged appearance; they were profusely lined with green willow leaves. The date of laying must vary considerably, for we found eggs in all stages of incubation, from incomplete sets of fresh eggs to full sets of four or five, and young birds, some recently hatched and others nearly grown.
In the locality described above the anhinga’s nests were segregated in groups on the outskirts of heron rookeries or were in small rookeries by themselves, but they are often found mingled with various other species in the large rookeries. In the great Cuthbert rookery in southern Florida, which occupies a small mangrove island in Cutbbert Lake, we estimated, on our first visit on May 1, 1903, that the population consisted of about 2,000 Louisiana herons, 1,000 white ibises, 600 Florida cormorants, 200 anhingas, 100 little blue herons, 18 American egrets, and 12 roscate spoonbills; the total, about 4,000 birds, was really a wonderful population for so small an island, and I have no doubt that the estimate was well below the actual figures. The water-turkeys’ nests were scattered among the ibises and cormorants nests in the red mangroves and mostly over the water; they were similar to those described above and in most cases contained from three to five eggs, though there were also young of various ages.
Mr. Charles R. Stockard (1905) describes the nest of this species, as he has found it in Mississippi, as “rather loosely constructed of sticks and very shallow, suggesting at once the architectural style so commonly empl6yed by the herons,” apparently unlined and without leaves. Other writers have referred to nests lined with willow catkins, cypress needles, and Tillan,dsia. The water-turkey returns to the same nesting site and probably uses the same nest year after year, which may account for the presence of dead leaves in the nest, the remains of previous years’ linings.
Eggs: The full set usually consists of four eggs, sometimes only three and sometimes five. The eggs are often laid at irregular intervals, as the young in a nest are frequently of widely different ages. The eggs have been described as resembling other eggs of the Steganopodes, but to me they look quite different and easily recognizable. The shape varies from “ovate,” slightly elongated, to “elliptical ovate” or “elongate ovate.” The ground color is pale bluish white, which is usually more or less covered with a very thin coating of chalky deposit, rarely roughly or thickly covered with it; this is generally quite smooth, and after the egg has been incubated for a while it even becomes quite glossy. The color is always more or less concealed by brownish, buffy, or yellowish nest stains, which will not wash off; some eggs are uniformly stained a rich cinnamon or buff color over the entire surface.
The measurements of 42 eggs in the United States National Museum average 52.5 by 35 millimeters; the eggs showing the four extremes measure 57.5 by 35, 54 by 37.5, 47 by 33.5, and 53.5 by 33 millimeters.
Young: The young remain in the nest or near it until they are fully grown and able to fly, using both bills and feet to climb out of the nest and over the surrounding branches. Audubon (1840) says on this subject:
At an early age the young utter a low wheezing call, and at times some cries resembling those of the young of the smaller species of herons. From birth they are fed by regurgitat~on, which one might suppose an Irksome task to the parent birds, as during the act they open their wings and raise their tails. I have not been able to ascertain the period of incubation, but am sure that the male and the female sit alternately, the latter, however, remaining much longer on the nest. Young anhingas when approached while In the nest cling tenaciously to it until seized, and if thrown (lown they merely float on the water and are easily captured.
Plurmages: The young snake bird, when first hatched, is naked and yellowish buff in color, very different from the jet-black young of cormorants, but it soon becomes covered with a short, thick coat of soft buff-colored down, which contrasts prettily with its black bill. The peculiar snake-like attitude of the head and neck give the young bird a very curious appearance at this age. Audubon (1840) says of the development of the young:
When they are three w’eeks old, the quills and tail feathers grow rapidly but continue of the same dark-brown color, and so remain until they are able to fly, when thoy leave the nest, although they still present a singular motley appearance, the breast and back being buff-colored, while the wings and tall are nearly black. After the feathers of the wings and tail are nearly fully developed, those of the sides of the body and breast become visible through the down and the bird appears more curiously mottled than before.
In the juvenal or first winter plumage the sexes are practically alike; the flight feathers of the wings and tail are plain dusky; the belly is dark brown and the breast and neck lighter brown, sometimes pale cinnamon on the chest; the upper parts are brownish black with a limited amount of the silver-gray markings so conspicuous in adults on the back, scapulars, and wing-coverts; these markings are more restricted and less brilliant than in adults and are bordered with brownish. I have seen young birds, still partially in down, in which these silver-gray markings were well developed. A prenuptial molt occurs during the first spring, which involves part or all of the body plumage, the tail and perhaps also the wings. This molt brings progress toward maturity, but the wings and tail are still plain dusky, lacking the characteristic corrugations of the latter or having them only faintly suggested; there is an increase in the silvergray markings of the upper parts and more black appears in the belly, but the head, neck, and chest are still light brown in both sexes. At the first postnuptial molt, during the following summer and fall, a plumage approaching the adult is assumed and the sexes become differentiated. This is a complete molt at which the adult wings and tail are assumed and at which the male acquires the black chest, neck, and head; but signs of immaturity still remain in the shape of scattering brown feathers, which give the head and neck of the young male a mottled appearance. The fully adult plumage is not completed until the following spring, when the young bird is nearly two years old.
The adult winter plumage is similar to the adult nuptial plumage, except that the scattering light-colored plumes of the head and neck are lacking, also the elongated dark mane of the hind-neck. The prenuptial molt is nearly complete; the tail is molted in April, beginning with the central rectrices; I have seen birds in early summer which had apparently fresh remiges, but I have never seen them actually molting these feathers in the spring. The postnuptial molt is probably complete, though I have not fully traced it and can not say just when it occurs.
Food: Audubon (1840) found in the stomachs of this species “fishes of various kinds, aquatic insects, crays, leeches, shrimps, tadpoles, eggs of frogs, water-lizards, young alligators, water-snakes, and small terrapins,” certainly a varied bill of fare. He also relates the following incident to illustrate its voracity:
One morning Doctor Bachman and I gave to an anhinga a black fish, measuring nine and a half inches by two inches In diameter; and although the head of the fish was considerably larger than Its body, and its strong and spinous fins appeared formidable, the bird, which was then about seven daonths old, swallowed it entire, head foremost. It was In appearance digested In aS hour and a half, when the bird swallowed three others of somewhat smaller size. At another time we placed before it a number of fishes about seven and a half inches bag, of which it swalloxved nine in succession. It woul(l devour at a meal forty or more fishes about three inebes and a half long. On several occasions it was fed on plaice, when it swallowed some that were four inches broad, extknding its throat, and compressing them during their (lescent into the stomach. It (lid not appear to relish eels, as it ate all the other sorts first, and kept them to the last; and after haviug swallowed them, it had great difficulty in keeping them down, but, although for awhile thwarted, it would renew its efforts, and at length master them. ‘When taken to the tide-point at the foot of my friends garden, it would now and then after diving return to the surface of the water with a cray-fish in its mouth, which it pressed hard and dashed ahout in Its hill, evidently for the purpose of maiming It, before it would attempt to swallow It, and it never caught a fish without bringing it lip to subject it to the same operation.
Fish undoubtedly form the principal part of this bird’s diet and it is especially well adapted to catch them, with its skill as a diver, its speed under water and its long neck, controlled by highly developed, special muscles and armed with a spearlike beak, which may be darted in any direction swiftly and accurately. Mr. N. B. Moore’s unpublished notes on this species in Florida show that it does not fish exclusively in fresh water, for he frequently saw it diving in the tidal waters of a bay between two oyster bars.
Behavior: Though ungainly in appearance and somewhat awkward in its movements when perched on a tree, it is really a graceful bird on the wing with splendid powers of flight; it clings somewhat clumsily to the branch on which it sits, but its totipalmate feet hold it securely, as it spreads its broad wings in the sun to dry them or flaps them vigorously for exercise, its ample tail serving to balance it. As it launches into the air it is evident that the broad expanse of wings and tail, in proportion to its small, compact body, are amply sufficient to sustain it in rapid, strong, and protracted flight. The neck is outstreached, usually to its full extent, but sometimes with a partial fold near the body, the tail is spread as a rudder and the wings are moved rather rapidly as the bird forges steadily ahead in a straight line. Like other Steganopodes, it sets its wings and scales at intervals, when it suggests, in appearance and manner, the flight of a Cooper’s hawk. One of the favorite pastimes of a flock of waterturkeys is to indulge in aerial exercise by rising from their roost, mounting high in the air and soaring in circles gradually upwards until almost out of sight, stiggesting in their movements the flight of the Buteos. After gazing in admiration at such a spectacle the observer may be suddenly surprised to see one after another of the birds fold its wings and dart downwards, swift as an arrow.
In the water it is even more at home than in the air, where it swims gracefully and swiftly on the surface or sneaks away with its body stibmerged and only its snake-like head and neck showing in sinuous curves; sometimes only its bill is seen cutting the smooth surface and making scarcely a ripple. In pursuit of its prey it does not plunge from the air into the water, but dives from the surface, disappearing like a flash with the least possible effort or commotion, like a master diver with perfect control of its movements in its favorite element. Under water its long slender body is propelled by the powerful feet alone, the wings tightly folded and the broad tail guiding its movements.
Audubon (1840) says of its roosting habits:
The anhinga is altogether a diurnal bird, and, like the cormorant, is fond of returning to the same roosting place every evening about dusk, unless prevented by molestation. At times I have seen from three to seven alight on the dead top branches of a tall tree, for the purpose of there spending the night; and this they repeated for several weeks, until on my having killed some of them and wounded others, the rest abandoned the spot, and after several furious contests with a party that roosted shout two miles off succeeded in establishing themselves among them. At such times they seldom sit very near each other, as cormorants do, but keep at a distance of a few feet or yards, according to the nature of the branches. Whilst asleep they stand with the body almost erect, hut never bend the tarsus so as to apply it in its whole length, as the cormorant does; they keep their head snugly covered among their scapulars, and at times emit a wheezing sound, which I supposed to be produced by their breathing. In rainy weather they often remain roosted the greater part of the day, and on such occasions they stand erect, with their neck and head stretched up~vards, remaining perfectly motionless, as if to allow the water to glide off their plumage. Now and then, however, they suddenly ruffle their feathers, violently shake themselves, and again compressingtheir form, resume their singular position.
Aside from the whistling notes, referred to above as a part of their courtship performances, their only utterances are the rough, grunting call notes, much like the sounds made by cormorants. Eve7i these are not often heard, as the birds are usually silent. I have never noticed anything worthy of comment in their behavior toward other species; they seem to be peaceful and harmless neighbors in the large, mixed rookeries where they breed; and, so far as I know, they seem to have no serious enemies. They attend strictly to their own affairs, have their own favorite haunts and usually flock by themselves. They are practically useless for food and their plumage is not in demand.
Winter: At the approach of winter the waterrturkeys withdraw from their northern breeding grounds and spend the winter in Florida and the Gulf States. At this season they become more gregarious and are often seen flying about in large flocks.
Breeding range: Tropical and subtropical regions in North and South America. In the United States, north to south central Texas (Bexar County),eastern Arkansas (Helena),southern Illinois (Cairo and Mount Carmel), and southern North Carolina (near Wilmington). Southern limits of South American breeding range not well defined, but the species ranges south to southern Brazil, Paraguay, and northern Argentina, and it probably breeds throughout most of its range. Said to breed on the coast of Peru.
Winter range: Jncludes most of the breeding range, at least north to central Arkansas (Newport), central Alabama (Greensboro), and probably southern Georgia.
Spring migration: Migrates into South Carolina in March (earliest, March 13, usually common by March 21).
Fall migration: Latest dates: Illinois, Cairo, August 31; South Carolina, Otranto, August 31.
Casua1 records: Has wandered as far west and north as California (Imperial County, February 9, 1913), Wisconsin (Kelley Brook, spring, 1889), and Ohio (Lowell, November, 1885).
Egg dates: Florida: Fifty-four records, February 15 to June 16; twenty-seven records, March 16 to April 29. Louisiana and Texas: Eight records, April 14 to June 2; four records, April 21 to May 2T.