Due to its remote northern breeding areas, much of what is known about Black Scoters range and reproduction has been learned relatively recently. Pairs are generally solitary, though while molting and during winter larger flocks may form. Rushing chases by Black Scoter males may occur during courtship.
It is thought that Black Scoters do not breed until age two, and there is little data to indicate how long they typically live. Both hunting and oil spills are known sources of mortality, but relatively little information is available regarding the major sources of mortality.
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Description of the Black Scoter
The Black Scoter is a sea duck with a stocky build and mostly dark plumage.
– Black plumage.
– Yellow knob on bill.
Brownish plumage with a paler lower face and throat.
Seasonal change in appearance
Similar to adult females.
Mollusks and insects.
Forages by diving.
Breeds in Alaska and northeastern Canada and winters along both coasts of North America. Population generally stable.
Bent Life History
Visit the Bent Life History for extensive additional information on the Black Scoter.
The shape of a bird’s wing is often an indication of its habits and behavior. Fast flying birds have long, pointed wings. Soaring birds have long, broad wings. Different songbirds will have a slightly different wing shape. Some species look so much alike (Empidonax flycatchers) that scientists sometimes use the length of specific feathers to confirm a species’ identification.
Wing images from the University of Puget Sound, Slater Museum of Natural History
Black Scoters are rare visitors to large inland lakes during the winter.
While usually seen in pairs during the breeding season, scoters often form small flocks during the winter.
Males make a long whistling sound.
White-winged Scoters have white wing patches, white below and behind the eye.
Male Surf Scoters have white head patches, while females have dark faces with small white patches
The nest is plant-lined depression on the ground.
Color: White or buff.
Incubation and fledging:
– Young hatch at 27-31 days.
– Young fledge (leave the nest) soon after hatching but remain with the female for some time.
Bent Life History of the Black Scoter
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 Black Scoter – the common name and sub-species reflect the nomenclature in use at the time the description was written.
OIDEMIA AMERICANA Swainson
This is the least known and the rarest of the three species of scoters or “coots ” which migrate up and down our coasts on both sides of the continent; it is also the hardest of the three to identify in life, as it has no distinctive marks visible at a distance; hence it is commonly referred to by nearly all observers in connection with the other two, and it is very difficult to separate much that is applicable to this species alone. This group as a whole seems to be rather unpopular among naturalists, as it is among sportsmen; consequently comparatively little effort has been devoted to the study of its habits.
Spring: The spring migration of the American scoter, on the Atlantic coast, is eastward and northward along the seacoast; I can find no evidence of an overland flight to the interior, which is so conspicuous in the white-winged scoter. During April and the early part of May large numbers may be seen migrating eastward through Xinevard Sound and around Cape Cod. On the south coast of Labrador we saw them flying eastward during the latter part of May and the first half of June. ‘While migrating the three species usually keep in flocks by themselves, but mixed flocks are occasionally seen; such mixed flocks are more apt to contain American and surf scoters than white-winged scoters.
Nesting: Dr. E. W. Nelson (1887) writes:
At St Michael these ducks are never seen in spring until the Ice begins to break offshore and the marshes are dotted with pools of open water. May 16 is the earliest date of arrival I recorded. Toward the end of this month they leave the leads in the ice and are found in abundance among the salt and fresh water ponds on the great marshes from the Yukon mouth north and south. The mating is quickly accomplished and a nesting site chosen on the border of some pond. The spot is artfully hidden in the standing grass, and the eggs, if left by the parent, are carefully covered with grass and moss. At the Yukon mouth Dali found a nest of this species on June 17. The nest contained two white and rather large eggs, and was in a bunch of willows on a small island, and was ~vell lined with dry grass, leaves, moss, and feathers.
Edward Adams (1878) found this species breeding in the same general region, and says of its nesting habits:
These birds were rather late in their arrival; I met with none until the 19th of May. Toward the end of the month several pairs had taken possession of the larger lakes near Michalaski; here they remained to breed, seldom going out to sea, but keeping together in small flocks in the middle of the lake. Their nests were well secreted in the clefts and hollows about the steep banks of the lakes, close to the water; they were built of coarse grass, and well lined with feathers and down. They had not laid when I last examined the nests.
Audubon’s (1840) historic account of the nesting of the American scoter on the south coast of Labrador is interesting as showing that it once bred farther south than it now does and as illustrating its method of nesting in Labrador, where it probably still breeds abundantly in the more remote sections; he writes:
On the 11th of July, 1833, a nest of this bird was found by my young companions in Labrador. It was placed at the distance of about 2 yards from the margin of a large fresh-water pond, about a mile from the shore of the Gulf of St. Lawrence, under a low fir, in the manner often adopted by the eider duck, the nest of which it somewhat resembled, although it was much smaller. It was composed externally of small sticks, moss, and grasses, lined with down, in smaller quantity than that found in the nest of the bird just mentioned, and mixed with feathers. The eggs, which were ready to be hntched, were S in number, 2 inches in length, an inch and five-eighths in breadth, of an oval form, smooth, and of a uniform pale yellowish color.
We did not observe this species on the south coast of Labrador except as a migrant, but on the east coast we found it fairly common all summer all along the coast, at least as far north as Hopedale. Flocks made up entirely of males were seen in many of the inner bays and in the mouths of rivers in July and August; probably their deserted mates were incubating on their eggs or tending broods of young about the inland ponds a few miles back from the coast.
It is surprising that none of the numerous ornithologists who have visited Labrador have ever found and identified a nest of the American seoter since Audubon’s time, but anyone who has ever attempted to explore into the interior of this discouraging country will appreciate why. The region is so vast, so hopelessly impassable, and so exceedingly poor in bird life that one soon gives it up in despair. This and all other species are so widely scattered that the chances of finding their nests are very small. I doubt if the American scoter migrates very far north to breed; we did not see it north of Hopedale, though we did see the surf scoter; it has never been found breeding abundantly about Hudson Bay in the northwest territories or on the Arctic coast, and Turner reported it as very scarce about Ungava Bay. Its main breeding grounds have apparently never been found. One would naturally infer then that the large numbers of this species which winter on our eastern coasts must breed in the interior of the Labrador peninsula, probably in the southern half of it, and perhaps near the marshy coasts of James Bay and the southern half of Hudson Bay; all of which regions are sadly in need of further exploration.
The American scoter undoubtedly breeds regularly, but not abundantly in Newfoundland. My friend, J. 11. Whitaker, told me that he had seen this duck on Grand Lake with a brood of young, though his attempts to find a nest have proved unsuccessful. This is another vast region, difficult to travel in and largely unexplored.
I have a set of 9 eggs in my collection, said to be of this species, taken by Rev. C. E. Whitaker on Gary Island, Mackenzie Bay, on June 10, 1910; the nest is described as made of down in a tussock of grass. The down is rather dark in color, varying from “bone brown” to “dusky drab” and is flecked with bits of whitish dawn, uniformly mixed with the dark down; the down is mixed with bits of dry leaves, pieces of grass, and small sticks.
Eggs: The American scoter is said to lay from 6 to 10 eggs. They vary in shape from ovate to elliptical ovate. The shell is clean and smooth, but without gloss. The color varies from “light buff’~ or “pale pinkish buff” to “cartridge buff.” The measurements of 58 eggs, in various collections, average 01.9 by 41.7 millimeters; the eggs showing the four extremes measure 72.5 by 46, 03 by 46.2, and 53 by 33.6 millimeters.
Young: Nothing seems to be known about the period of incubation. This duty is performed solely by the female, who is entirely deserted by the male at this season. Doctor Nelson (1887) writes:
As the set of eggs is completed, the male gradually loses Interest in the female and soon deserts her to join great flocks of his kind along the seashore, usually keeping in the vicinity of a bay, inlet, or the mouth of some large stream. These flocks are formed early in June and continue to grow larger until the fall migration occurs. Males may be found in the marshes with females all through the season, but these are pairs which breed late. A set of fresh eggs was taken on August 3, and a hrood of downy young was obtained oa Septeniber 9. The habits of these flocks of males are very similar to those of the male elders at this season. They are good weather indicators, nod frequently, 10 or 20 hours in advance of a storm, they come iato the sheltered bays, sometimes to the number of a thousand or more. At such times they show great uneasiness, and frequently pass hours in circling about the bay, sometimes a hundred yards high and again close over the water, the shrill whistling of their wings making a noise which is distinctly audible nearly or quite half a mile. Until the young are about half grown the female usually keeps them iii some large pond near the nesting place, but as August passes they gradually work their way to the coast and are found, like the eiders of the same age, along the reefs and about the shores of the inner bays until able to fly.
Regarding the care of the young, Audubon (1840) says:
I afterwards found a female with seven young ones, of which she took such effectual care that none of them fell into our hands. On several occasions, when they were fatibmed by diving, she received them all on her back, and swiihming deeply, though very fast, took them to the shore, where the little things lay close among the tall grass and low tangled bushes. In this species. as in others, the male forsakes the female as soon as incubation commences.
Plumages: The downy young, when first hatched, is dark colored above, varying from “Prout’s brown” or “verona brown” to “bister,” darkest on the crown and rump; the throat and cheeks, below the lores and tile eyes, are white; the under parts are grayish white centrally, shading ofF on the flanks into the color of the upper parts; the bill is broadly tipped with dull yellow. The plumage appears first, when about half grown, on the breast and scapulars; the tail appears next and the wings are the last to grow.
The following remarks are based largely on two papers by Gurdon Trumbull (1892 and 1893) and one by Dr. Jonathan Dwight (1914) on the molts and plumages of the scoters, all of xvhich are well worth reading, and to which I would refer the reader for details. In the juvenal plumage the sexes are practically’ alike, the female averaging slightly smaller. The tipper parts, including the crown, back, wings, and tail, are deep, rich brown, varying from “Prout’s brown” to mummy brown,” darkest on the scapulars and tertials and palest on the neck, chest, and flanks, where it fades into the light color of the under parts; the lower half of the head and the belly are grayish white, mottled with lighter browns. This is the plumage in which the birds are known to the gunners as “gray coots”; it is worn during the fall and often well into the winter without change. Sometimes as early as November, but more often not until January or later, the sexes begin to differentiate; a growth of black feathers begins in the head and neck of the young male and a similar growth of brown feathers appears in the young female. The growth of black feathers in the male increases during the winter and spring until some of the most advanced birds become nearly all black except on the belly and wings. Doctor Dwight (1914) says:
Shortly after new feathers appear, the bill of the young male begins to take on the colors of the adult and still more gradually assumes its shape. Tue colors may closely approximate, by the end of the winter, those of the adult, but the shape is not perfected for at least a year, the swelling of the hump not bejag marked in the first winter birds, although the yellow color may he brilliant. The bill of the female and the legs and feet of the male remain dusky, adults differing very little from young birds.
No matter how black the plumage may be nor how bright the colors of bill or feet, young males may infallibly be told from adults by the shape of the first primary, which is not replaced until the first postnuptial molt. The iris in americana is ahvays bro~vn in both sexes at all ages.
At the first complete postnuptial molt, the following summer, the young bird becomes practically adult; the plumage is wholly black in the male and wholly dark brown in the female. At this molt the adult wing is acquired, in which the outer primary is deeply emarginated; the broad tipped outer primary is worn by the young bird for one year only.
Adults have two molts each year, a partial prenuptial molt in March and April, involving the body feathers and the tail, and a complete postnuptial molt in August and September. There is no evidence of anything like an eclipse plumage in this or in the other scoters. The plumages described as such by European writers are probably produced by wear and fading or by left-over traces of a former plumage.
Food: Writing of the feeding habits of the three species of scoters on the Massachusetts coast, George H. Mackay (1891) says:
These scoters are the most numerous of all the sea fowl which frequent the New England coast, collecting in greater or less numbers wherever their favorite food can be procured: the black mussel (Modiola modiolus), small sea clams (Spisula solidisstrna), scallops (Pecten coaccatricas), and short razor shells (Siliqua costata), about an inch to an inch and a half long, which they obtain by diving. Mussels measuring 21~ inches by 1 inch have been taken from them; but usually they select sea clams and scallops varying in size from a 5-cent nickel piece to a quarter of a dollar. They can feed in about 40 feet of water, but prefer less than half of that depth. As these mussels are frequently difficult to detach, and the sea clam lives embedded endwise in sand at the bottom with only about half an inch above the sand, the birds are not always successful in obtaining them, it requiring considerable effort on their part to pull the mussels off or to drag out the clams. Eight or ten of these constitute a meal, but the number varies according to the size. I have heard of a mussel closing on a scoter’s tongue, which was nearly severed at the time the bird was shot (Muskeget Island, about 1854). The fishermen frequently discover beds of shellfish (scallops) by noticing where these birds congregate to feed. In the shoal waters adjacent to Cape Cod, Nantucket and Marthas Vineyard, these mollusks are larticularly abundant, and consequently we find more of the scoters in those localities than on any other part of the coast or perhaps than on all the rest of the coast combined.
E. H. Forbush (1912) writes:
Its food consists largely of mussels, and when feeding on fresh water it prefers the Unios or fresh-water clams to most other foods. Thirteen Massachusetts specimens were found to have eaten nearly 95 per cent of mussels; the remaining 5 per cent of the stomach contents was composed of starfish and periwinkles. It is a common belief that all scoters feed entirely upon animal food, but this is not a facL Along the Atlantic coast they appear to subsist mostly on marine animals, but, in the interior, vegetable food also is taken. Mr. W. L. MeAtee found the scoters in a Wisconsin lake living almost exclusively for a time on the wild celery, but he does not state definitely what species of scoter was represented there.
Dr. F. Henry Yorke (1899) says that, while on the lakes and ponds of the interior, this species eats minnows and small fish, slugs, and snails, larvae of insects, fish spawn, crawfish, small frogs, and polliwogs; also a variety of vegetable food such as duckweed, pondweed, flags, water milfoil, bladderwort, and several other water plants. Probably the young are fed largely on insect food.
Behavior: The American scoter is not easily recognized in flight; its size, shape, gait, and general appearance are all much like those of the surf scoter, from which only the adult males can be distinguished by the head and bill markings at short range; the females and young of these two species can not be distinguished in life at any considerable distance, and many gunners do not recognize them in the hand. Its flight is not quite so heavy as that of the white-winged scoter. All the scoters fly more swiftly than they appear to be going, but at nothing like the speed at which they have been reported to fly; I doubt if they ever fly at over 60 miles an hour or even attain that speed except under the most favorable circumstances. Migrating flocks in the fall usually fly high in fair weather, but in stormy or very windy weather the flocks sweep along close to the water and usually well in shore, following the indentations of the coast line and seldom flying over the land, except on their occasional visits to inland ponds. The flocks vary greatly in size and form, some are great irregular masses or bunches, others are strung out in long straight or curving lines, and sometimes they form in more or less regular V or U shapes. The wings make a whistling sound in flight, which the gunners imitate to attract the attention of passing flocks.
All the scoters are strong, fast, and tireless swimmers, either on the surface or below it; they dive quickly and neatly and can remain under water for a long time. Mr. Mackay (1891) writes:
In these shallow waters the tide runs rapidly over the shoal ground and sweeps the scoters away from where they wish to feed, thus necessitating their flying hack again to it; consequently there is at such times a continual movement among them as they are feeding. When wounded and closely pursued, they ivill frequently dive to the bottom (alxvays using their wings as well as feet at such times in swimming under water) and retain hold of the rockweed with the bill until drowned, prefering thus to die than to come to the surface to be captured. As an instance of this, I may mention that on one occasion I shot a scoter when the water was so still that there was not even a ripple on its surface; after pursuing the bird for some time I drove it near the shore, when it dove and did not reappear. I knew it must have gone to the bottom, as I had seen the same thing repeatedly before. As the occasion was a favorable one for investigation, the water being clear and not more than 12 or 15 feet in depth, I rowed along carefully, looking continually into the water near the spot where the bird was last seen. My search was at last successful, for on getting directly over where the bird was I could look down and distinctly see it holding on to the rockweed at the bottom with its bill. After observing it for a time I took one of my oars, and aiming it at the bird sent it down. I soon dislodged it, still alive, and captured it. I have often seen these birds, when wounded and hard pressed, dive where the water was 40 to 50 feet deep, and not come to the surface again. I therefore feel much confidence in stating that it is no uncommon occurrence for them under such circumstances to prefer death by drowning to capture. This they accomplish by seizing hold of the rockweed at the bottom, holding on even after life has become extinct. I have also seen all three species when wounded dive from the air, entering the water without any splash. All are expert divers, it requiring considerable experience to retrieve them when wounded.
Scoters are usually silent birds; I can not remember having heard any notes from any of them, but Mr. Mackay (1891) says: “The American scoter makes a musical whistle of one prolonged note, and it can frequently be called to the decoys by imitating the note.” Rev. ,J. II. Langille (1884) says: ” The note of the scoter in spring is like whe-oo-lwo, long drawn out.”
Maj. Allan Brooks (1920) writes:
In British Columbia this scoter is an exclusively maritime duck; at least I have not come across a single reliable Inland record. Not only is it a maritime bird, but it is seldom found in the small bays and inlets where the other species swarm, but frequents the exposed shores and outer reefs together with the harlequin. It has many points in common with that duck, rising easily from the water and doing much flying about in small lots of four or five: mostly males: seemingly for the pleasure of flying, usually returning to the point they started from. In flight the silvery undersurface of the primaries, in both sexes, is very conspicuous. In fine, calm weather they call a great deal and their plaintive coax-Leo is the most musical of duck cries, very different from the croaking notes of most diving ducks.
Fall: The fall migration of the American scoter is somewhat earlier than that of the other two species. On the Massachusetts coast the flight begins in September, and during the latter half of that month there is often quite a heavy flight which consists almost entirely of adult birds. The young birds, which are known as “gray coots,” come along with the other scoters in October. Each species usually flocks by itself, and flocks of adults are often separated from flocks of young birds; but mixed flocks are often seen, particularly of young American and surf scoters. The American scoter is more often seen in fresh-water ponds a few miles back from the coast than are the other two, though all three are often seen on our large inland lakes.
Game: From the sportsman’s standpoint the American scoter is a more desirable game bird than the other two scoters. The young birds particularly, when they first arrive from their northern feeding grounds in the interior, are fatter, more tender, and less strongly flavored than are the others. The value of ” coots ” as food has been much maligned and in my opinion unjustly; if young and tender birds are selected and if they are properly cooked their flesh is much more palatable than is generally supposed; the popular prejudice against them is largely due to an erroneous impression that they must be parboiled, which is a pernicious practice and will render any oily seaduck unfit for food by saturating the flesh with the oily flavor. There are only two proper ways to cook a sea duck; one is to skin it and broil it; and the other is to scrape as much oil out of the skin as possible and then roast it quickly in a hot oven, letting the oil run off.
The Massachusetts method of ” coot shooting,” in which I have often indulged, is described under another species, so I shall quote from Walter H. Rich (1907) as to the methods employed on the Maine coast; he writes:
Probably the least wary of the duck family, they may be approached quite readily as compared with other members of the tribe. Gunners use many methods for capturing the coots, but the greater number are killed dyer decoys. A string of “tolers” is set in a promising place just off some rocky point or ledge in the deep water, the gunner is well hidden, and if the birds are flying there is every prospect of good shooting, for the coot is one of the best of birds to decoy. Often in the early part of the season, before the birds have become shy from constant peppering, the gunner may set his decoys on a line from his boat, only keeping below the gunwale when the flocks are coming in. And they intl come in. I have often seen them fly close enough to be struck with an oar: I may say that they make it an invariable rule to do this when tile gunner has taken the shells out of his gun or laid it aside to pick up his decoys after a morning’s cootless waiting in the cold. One oddity in the gentle art of duck shooting is the practice of “hollerin’ coots “: that is, of making a great noise when a flock is passing by out of shot: when they will often turn and come to the decoys. The report of a gun sometimes has the same effect, but we New Englanders are too thrifty to waste powder and lead where our vocal organs will serve as well.
Next to decoying, the use of the “gunning float” is the most effective method of killing coots. The “gunning float” is a long, low craft, drawing but little water and showing only a foot or so above the surface when properly trimmed dawn with ballast. In the fall, for use in the open water, they are “trimmed” with “rockweed”; In the marshes with “thatch.” In the spring and winter months the proper thing is snow and ice to represent a drifting ice cake. It takes sharp eyes to detect the dangerous one among the many harmless pieces of ice when the gunner, clad in his white suit, is working his cautious way along toward the feeding flocks. The deception is so complete that I have known that crafty old pirate, the crow, to almost alight on the nose of a float ~vhea it was being pushed after a flock of sea fowl. This float gunning is the method most used for all duck and goose shooting on the eastern New England coast line.
Winter: There is not a month in the year during which scoters may not be seen on the Massachusetts coast; straggling birds, crippled, sick, or nonbreeding birds are present more or less all summer; the heavy migration flights last all through the fall and during much of the spring; and iii winter this is one of the main resorts of all three species. The waters lying south of Cape Cod and in the vicinity of Nantucket and Marthas Vineyard are particularly congenial to these birds in winter, where the numerous islands, bays, and reefs offer some shelter from the winter storms, where they are not much disturbed by gunners at that season, and where they can find extensive beds of mussels, scallops, clams, and quahogs within easy reach on the numerous shoals and ledges. Here they congregate in enormous numbers, the three species associated together and often with eiders and oldsquaws. They have their favorite feeding grounds, to which they resort regularly every day at daybreak, feeding, playing, and resting during the day and flying out again at night to sleep on the bosom of the ocean, or on some more sheltered portion of the sound, far enough from land to feel secure. DISTRIBUTION Breeding range: Northern North America and northeastern Asia. East to the coast of Labrador (north of the Straits of Belle-Isle) and Newfoundland (Grand Lake). South nearly or quite to the Gulf of St. Lawrence, to James Bay, to an unknown distance in the interior of Canada and Alaska and to the base of tile Alaska Peninsula (Lake Clark). On the Aleutian and Kurile Islands. West to the Bering Sea coast of Alaska and to northeastern Siberia (Gichiga). North to northern Alaska (Kowak River), northern Canada (Mackenzie Bay) and probably north in the Labrador Peninsula to Ungava Bay and perhaps Hudson Straits.
Winter range: Mainly on the seacoast. On the Atlantic coast regularly south to Long Island Sound and New Jersey, rarely to South Carolina, and occasionally to Florida. North regularly to Maine and more rarely to the Gulf of St. Lawrence and Newfoundland. On the Pacific coast from the Pribilof and Aleutian Islands south to soutllern California (Santa Barbara Islands) and from the Commander Islands south to Japan and China. In the interior it winters on the Great Lakes more or less regularly and has occurred irregularly or casually as far west and south as Wyoming (Cheyenne), Colorado (Fort Collins), and Louisiana (Lake Catherine).
Spring migration: Early dates of arrival: Gulf of St. Lawrence, March 25; Ontario, Ottawa, May 4; Alaska, St. Michael, May 16, and Bering Straits, May 8. Late dates of departure : South Carolina, Bulls Bay, May 7; Virginia, Cobb Island, May 19; New York, Shelter Island, June 5; Massachusetts, Woods Hole, June 10; Alaska, Admiralty Island, June 10.
Fall migration: Early dates of arrival: Ontario, Ottawa, September 1; Massachusetts, September 8; Minnesota, Heron Lake, October 5; Colorado, Denver, October 2. Main flight passes Massachusetts in October. Late date of departure: Alaska, St. Michael, October 15.
Egg dates: Arctic Canada: Five records, June 10 to 21. Alaska: Four records, June 2 to August 3. Labrador: Two records, June 10 and 17.