Despite a large distribution worldwide, the Great Cormorant breeds in only a limited portion of North America in the northwestern portion of the Atlantic Ocean. Larger than the other cormorants in North America, the Great Cormorant is also marine in occurrence, and is seldom seen inland.
Great Cormorants don’t typically breed until three years of age. Cold weather is one source of chick mortality. Becoming entangled in fishing lines or nets is one source of adult mortality, but banded Great Cormorants have lived up to 14 years in the wild.
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Description of the Great Cormorant
The Great Cormorant is large in size with a short tail, a blocky head, brownish-black plumage, and a yellow throat patch surrounded by white feathers. White patch on flanks.
Seasonal change in appearance
Winter adults lack the white flank patch.
Brownish upperparts and neck, with a white belly.
Coastal areas and sea cliffs.
Forages by diving underwater.
Breeds in coastal areas of eastern Canada and the northeastern most U.S., and winters somewhat farther south along the Atlantic Coast of the U.S.
Great Cormorants travel up to 23miles from their nest to forage when feeding chicks.
The Great Cormorant is the largest cormorant in North America, but the largest fish it catches are no more than 7 or 8 inches long.
Grunts and loud, guttural calls are made on the breeding grounds.
- The Double-crested Cormorant is smaller, has a thinner bill, and has an orange throat pouch.
The nest is a mound of sticks and seaweed and is placed on a sheltered ledge.
Color: Pale blue or green.
Incubation and fledging:
– Young hatch at 28-31 days.
– Young fledge (leave the nest) in 50 days after hatching but remain with the adults for some time.
Bent Life History of the Great Cormorant
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 Great Cormorant – the common name and sub-species reflect the nomenclature in use at the time the description was written.
PHALACROCORAX CARBO (Linnaeus)
Now Great CormorantHABITS
On the northern Atlantic seaboard the term shag is used for both this and the double-crested species, and the two are not distihguished by the ordinary observer. Although not as common here as the double-crested bird, it has an almost world-wide distribution, and breeds in the northern part of the Northern Hemisphere from Nova Scotia, Labrador, and Greenland to the British Isles and Kamchatka, and winters as far south as Long Island, southern Africa, Australia, and New Zealand. The bird is said to be very intelligent, easily domesticated, and to become attached to its masters. In the time of Charles the First, fishing with trained corinorants was a regular sport in England, and this species was employed. Rings around the neck, as in China at the present day, were used to prevent swallowing the prey, although in well-trained birds this was unnecessary.
Although the cormorant does not now breed south of Nova Scotia, in the time of Audubon it nested at Grand Manan. Nuttall (1834) says, “They breed, and are seen in the vicinity of Boston on bare and rocky islands, nearly throughout the year.” Earlier still, when the first settlers came to this country, they were abundant along the New England coast, where now they are uncommon. Thus Wilham Wood (1634) writes:
Cormorants bee as common as other fowles which destroy abundance of small fish, these are not worth the shooting because they are the worst of fowles for ~eate, tasting ranke and fishy; againe, one may shoot twenty times and misse, for seeing the fire in the panne, they dive under the water before the shot comes to the place where they were; they used to roost upon the tops of trees, and rockes, being a very heavy drowsie creature, so that the Indians ~vill goe in their Cannoes in the night, and take them from the Itockes, as easily as women take a Hen from roost.
Spring: The birds arrive early on the breeding grounds and begin nesting before the snows of winter have disappeared. Frazar (1887) says that in southern Labrador it is sometimes the case that the frozen foundations of the nest give way under the summer heat, and the domicile and its contents are projected into the sea. He found large young in the nests at Cape Whittle, as early as June 19th.
Courtship: The courtship of the cormorant is spectacular and is performed both on the rocky ledges and cliffs and on the water. In the former situation the male approaches the female with an awkward waddle or hop and sinks down before her on his breast. In both situations the neck is stretched up to its full extent, with widely open beak and the brilliant inside lining of the mouth displayed. The tail is cocked up and the head stretched back and down until it touches the back. Selous (1901) says that “in this attitude he may remain for some seconds more or less, having all the while a languishing or ecstatic expression, after which he brings his head forward again, and then repeats the performance some three or four, or perhaps half a dozen times.~~ Nesting: iRocky cliffs are chosen by these birds for their nesting colonies, and, as a rule, they l)refer the elevated stations while the double-crested species nests for the most part on low rocks or on the lower portions of the cliffs. At Whapatiguan, the breeding place in southern Labrador made famous by Audubon, this species was found by Bryant (1862) to nest on the higher parts of the cliffs, while the double-crested nested lower down, although he found that the highest nest of all belonged to the double-crested species. Frazar (1887) at this place observed the double-crested nests all over the cliff, but those of car~o close to the top only. Brewster (1884) visited a colony of 20 pairs at Wreck Bay, Anticosti, and says the nests were situated “on the projections of a vertical limestone cliff some 15 feet below the summit and at least 100 above the sea.” Audubon’s (1840) description of the colony at Whapatiguan is classic; he says:
We saw no nests of this species placed In any other siluations than tUe highest shelves of the l)recipitous rocks fronting the water and having a southern exposure * * ~. On some shelves eight or ten yards in extent, the nests were crowded together; but more usually they were placed apart on every secure place without any order; none, however, were below a certain height on the rocks, nor were there any on the snmlnit.
Yarrell (1871) speaks of an island in county Cork, Ireland, where a colony of 18 pairs of cormorants had built their nests in Scotch fir trees not under 60 feet in height. He also speaks of their nesting in trees in Norfolk and Sicily.
The cormorant has not reached the point in evolution where sanitation and cleanliness about the dwelling place are considered important. A cormorant colony can be smelt from afar, and the vile, fishy odor clings to the clothes and remains long in the memory. Rocks, sticks, bushes, nests, eggs, everything is daubed with the chalky, slimy excrement. The nests are placed close together, or scattered wherever there are suitable ledges on the cliffs. In construction the nest is a bulky affair composed of twigs and branches of trees, grass stalks, pieces of mountain cranberry and curlew berry vine, seaweed, and fresh evergreen boughs. It measures about 10 inches inside and 20 to 24 outside and 3 or 4 inches high. Some of the nests, however, are fully a yard across and a foot high and are built upon the nests of preceding seasons.
Eggs: The eggs are four or five in number and occasionally six, and one set only is laid. They are somewhat larger than those of the double-crested species and are more rounded or ellipical in shape. They are of a faint green or blue color overlaid with a thick, chalky coating which soon becomes soiled a dirty yellowish color.
The measurements of 42 eggs, in various collections, average 64.8 by 40.9 millimeters; the eggs showing the four extremes measure 70.5 by 43.5, 61 by 39.0, and 62 by 38.5 millimeters.
Young: Audubon (1840) graphically described his pleasure in watching a cormorant family at Whapatiguan: “The mother f ondled and nursed her young with all possible tenderness, disgorged some food into the mouth of each, and coaxed them with her bill and wings. The little ones seemed very happy, billed with their mother, and caressed her about the breast.” They grow rapidly and are fed by both parents who convey the partially digested fish in their capacious gullets. Into these the young thrust their heads and necks and forage to their hearts’ content.
Plumages: The young are not objects of beauty, as they appear to be all legs, feet, and head and are naked and of a dark leaden color; this also is the general color of their bill, eyes, and feet. Later they become clothed with a sooty colored down. When three or four weeks old, before they are able to fly, they take to the water and at this time, according to Lucas (1897) the external nostrils, which have been open, become closed as in the adult. The juveniles, when fully feathered, have a brownish gray back, a dark brown breast, and in the first winter plumage the belly is nearly white. In this respect they differ from double-crested cormorants, which have a light-gray breast shading down to black on the lower belly. With good glasses I have been able to distinguish the two species at the distance of a mile. In the full adult plumage both sexes are alike, and are blue black below and bronry slate-brown above. There is abroad band of white on the throat below the bare gular sac, there are scattered linear white feathers on the side of the head and upper neck, and there are patches of white feathers on the flanks. These white patches, but particularly the white feathers of the throat, are excellent field marks to distinguish this bird from the double-crested cormorant. The fowlers of Belfast Lough, Ireland, according to Patterson (1880) speak of the flank patch as “the watch that it carries under the wing.” The bill is grayish-black; yellowish white on the edges of both mandibles and at the base of the lower mandible. The iris is a light bluish green with a dull olive bare space above and a bright red space below. The gular sac is yellow, not orange as in the double-crested species. The feet are grayish black.
The distinctive white patches are worn by both sexes but for a brief time during the nuptial season. Yarrell (1871) reports some observations on this point on captive birds in the gardens of the London Zoological Society; the white feathers on the side of the head and neck began to appear January 4th, arrived at greatest perfection February 26th, began to disappear on April 2d, and were gone by May 12th; the white patches on the thighs began on January 24th, were complete in five weeks, began to disappear on June 16th and were almost entirely gone on July 30th. It is probably that three or four years are needed before the full adult plumage is attained.
Food: The cormorant is an expert on the wing and in the water, and its habits are very similar to those of its double-crested cousin. Its food consists entirely of fish, which it is able to follow under water with great speed and seize with its powerful hook-like bill. “When it appears on the surface it sometimes throws the fish up into the air in order to get a better hold; its gullet is so wide that its swallowing capacity is large. Most of the fish it captures are of no economic importance to man, but in some cases, no doubt, a toll is taken of useful fish. On Cape Cod I have seen cormorants perched on the fencing of fish weirs, and it is probable that they are not considered desirable visitors by the fishermen. With us the cormorant lS rarely seen away from the sea, although there are records from Lake Ontario. Stead (1906) says of it in New Zealand that it “is wlth us largely an inland bird, frequenting fresh-water lakes and rivers.” Yarrell (1871) writes that they follow the course of rivers many miles inland.
Behavior: The flight of the cormorant is heavy and heron like, with slow flapping of its broad wings. It often flies close to the water, and I have seen it touch the surface with its wing tips at each stroke From a flat station like a beach, or the water on calm days, it has considerable difficulty in rising, and strikes with its feet together in great hops several times before it can get away. From a cliff or buoy it launches itself into the air and descends in a great dawnward curve nearly to the water, sometimes even splashing the surface before it gets impetus enough to rise again and fly away. The stronger the wind to which it opposes its aeroplanes, the less is the depth of the curve. The reverse process of alighting on a cliff, and particularly on a small perch like a buoy, also calls for much skill on the part of the bird, and is interesting to watch. The cormorant flies with considerable velocity upwind toward its buoy, sets its wings, and with neck outstretched and feet dropped, it sails upwards toward its perch. If it has not calculated exactly right it may fail to accomplish the feat; whereupon it swings around to leeward and tries again. I watched a cormorant try four times one calm March day off IRockport on Cape Ann before it succeeded in alighting on the spindle on the salvages. Cormorants, in migration or when flying to and from their feeding grounds, maintain no regularity of flock arrangement. An irregular flock is common, as is also a perfect V-shaped formation, a long file, or a rank. In the latter case each successive bird in the rank is generally slightly behind his neighbor on one side. Although the flight is usually heavy, with slow wing beats, the birds are swift flyers in strong winds and, at times, soar like gulls or hawks to a great height.
On the water they are rapid swimmers, and they often swim with their body depressed so that the back is level with the surface. When alarmed they sink still lower so that only the head and neck are exposed. They not infrequently swim with the head and neck extended forward under water for the purpose of looking for fish. Under the surface they are especially at home, and progress with great swiftness. As the cormorant dives for fish he springs upward and forward and enters the water in a graceful curve with wings pressed close to the sides. Ileadly (1907) says: “The cormorant uses his feet alone to propel him [in diving] striking with both simultaneously, and holding the wings motionless, though slightly lifted from the body. The position of the wings must have given rise to the idea, common among fishermen, that the cormorant flies under water * * * but when you see him in a tank you can have no doubt that the legs are the propellers.” Selous (1905) made observations on wild birds seen under advantageous circumstances in a cave in the Shetlands and confirms the statement that the wings are not used in diving. Cormorants are also able to dart down from a height as from a cliff and dive into the sea. This they are apt to do when shot at or otherwise disturbed.
The position of the cormorant on a perch is very characteristic by reason of the long neck which takes on an S curve, and the long tail which points diagonally downward or is slightly elevated to clear the ground. The gait of this bird is a waddle of the most marked description. It may be seen asleep on rocks or sandbars with head buried in the scapulars and the tail elevated. At their nesting places in cliffs they support themselves on the vertical faces by their claws and tail like woodpeckers. The most characteristic attitude of the cormorant, however, is the spread-eagle one with wings widely open. This attitude is assumed on trees or buoys, on rocks or sand and even on the surface of the water: sometimes for minutes together. On one occasion I timed an individual who sat thus on a rock for ten minutes. The position is generally supposed to be assumed for the purpose of drying the wings, but, if so, it is not assumed by other water birds, who content themselves with flapping and shaking their wings. I have seen cormorants assume the spread-eagle position on foggy, rainy days, and I am inclined to think that the habit is derived from the same ancestors that bequeathed it, to the vultures, for cormorants and vultures are now believed to be allied.
The cormorant is not a song bird, and, as far as I know, he utters his feelings only in harsh, guttural croaks.
Although Longfellow has made us familiar with the “fierce cormorant,” this bird seems to get along peaceably with other birds. As already stated it nests in communities with the double-crested species. G. M. Allen (1918) quotes from the notes of B. F. Damsell the interesting case of a cormorant that took refuge in an oak tree from the attacks of two kingbirds. From the tree it fell to the ground and was found to have a broken wing that had healed.
Man, as always, is the cormorant’s worst enemy, although its flesh and eggs are so fishy that they are but indifferent eating. I have already quoted William Wood on the subject. Josselyn (1674) gives a similar verdict and describes more in detail the Indians’ method of capture. He says:
I have not done yet, nor must not forget the cormorant, Shape or Sharke; though I can not commend them to our curious palats. The Indians will eat them when they are fley’d, they take them prettily, they roost in the night upon some Rock that lyes out In the Sea, thither the Indian goes in his BirchCanow when the Moon shines clear, and when he is come almost to it, he lets his Canoiv drive on of Its self, when he is come under the Rock he droves his Boat along till he come just under th~ Cormorants watchman, the rest being asieep, and so soundly do sleep that they will snore like so many Piggs; the Indian thrusts up his hand of a sudden, grasping the watchman so hard round his neck that he can not cry out; as soon as he hath him in his Ca~now fast, he ciambreth to the top of the Rock, where walking softly he takes them up as he pleaseth, still wringing off their heads; when he bath slain as many as his Canow can carry, he gives a shout which awakens the surviving Cormoraat8, who are gone in an instant.
Bewick (1884) ; says:
At other times and places, while they sit In a dozing and stupifled state, from the effects of one of their customary surfeits, they may easily be taken by throwing nets over them, or by putting a noose around their necks.
Kumlien (1879), reports that the primaries of this bird were formerly in great demand by the Eskimos of Cumberland Sound for their arrows.
Winter: The fall migration of the cormorant along the Atlantic coast begins in October and the birds winter in favorable localities along the shore. One of these is Rockport on the end of Cape Ann. Here three or four individuals, the pitiful remnant of a much larger number, may generally be seen fishing about the Salvages: rocky islands in the outer harbor: and alighting on spar buoys and spindles.
Breeding range: Probably now extirpated as a breeding bird in North America; a few may still breed in Greenland. Formerly bred from central western Greenland (Godhaven, 090 north) and Baffin Land (Cumberland Sound) south to Newfoundland, southern Labrador (Whapitaguan) and the Bay of Fundy (Grand Manan). In the eastern hemisphere this form breeds in Iceland, on the Scandinavian and north Russian coasts, east to the Kola Peninsula, and south to the Faroe Islands, Scotland, England, Ireland and Wales. The birds of continental Europe and Asia are now regarded as subspeciflcally distinct.
Winter range: Prom southern Greenland, throughout its breeding range, and southward along the Atlantic coast, regularly to New York (Long Island) and occasionally to Maryland (Chesapeake Bay) and South Carolina (two specimens taken). On the other side of the Atlantic the winter range extends to the Canary Islands.
Spring migration: Has been noted in Rhode Island (Newport) as late as May 15, and in Massachusetts (Amesbury) as late as June 18.
Fall migration: Arrives in Rhode Island (Seaconnet Point) as early as September 15, and New York (Long Island) as early as September 22.
Casual records: Accidental inland: Ontario (Toronto, November 21, 1896), and New York (Oheida Lake, November 15, 1877).
Egg dates: Labrador: Twelve records, June 1 to 30; six records, June 16 to 20. British Isles: Seven records, April 22 to May 25; four records, April 28 to May 19. Greenland: April 28 to July 25 (Hagerup).