Occupying virtually all of the Pacific Coast at one time of year or another, the Glaucous-winged Gull is typically a short-distance migrant. Although a colonial nester, the Glaucous-winged Gull still has need to defend a nest space, and a variety of threat displays are used. If that fails, physical attacks can become quite violent.
Predation by Bald Eagles as well as other avian and mammalian predators takes its toll on Glaucous-winged Gulls, but the increasing availability of food from landfills has likely helped the population. While the record age for a Glaucous-winged Gull is 32 years, few ever surpass 15 years of age.
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Description of the Glaucous-winged Gull
The Glaucous-winged Gull is a large gull with pale gray upperparts, white underparts, a yellow bill with a red spot, and no black in the wingtips. White head in breeding plumage. Length: 26 in. Wingspan: 58 in.
Same as male.
Seasonal change in appearance
Winter adults have brown barring on the head and neck.
Brown overall, with a dark bill. Becomes progressively more similar to adults over a four-year period.
Fish, clams, and other marine life, as well as insects, eggs, and refuse.
Forages while walking, swimming, or in flight.
Resident along the northwestern coast of North America, and winters along all of the West Coast.
Bent Life History
Visit the Bent Life History for extensive additional information on the Glaucous-winged Gull.
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.
- Five Gull Comparison: From top, adult Herring, Thayer’s, California, Ring-billed, and Mew, all from Washington (angle of photo makes upper wings seem smaller than they are)
- Herring and Herring x Glaucous-winged Gull wing specimens for reseearch
- Thayer’s Gull wing specimens for research
- Glaucous-winged, Western, and Western x Glaucous-winged Gull wing specimens for research
- Mew Gull wing specimens for research
Wing images from the University of Puget Sound, Slater Museum of Natural History
Glaucous-winged Gull pairs often remain together for many years.
Glaucous-winged Gulls are known to hybridize with Western, Herring, and Glaucous Gulls.
A “kjau” call is commonly given, but yelps and “ka-ka-ka” calls are given as well.
Glaucous Gulls have white wingtips.
Iceland Gulls are smaller in size.
The nest is a scrape lined with grass, moss, or seaweed and is placed on the ground or a cliff.
Color: Olive or buff with darker markings.
Incubation and fledging:
– Young hatch at 26-29 days.
– Young fledge (leave the nest) in 37-53 days after hatching but remain with the adults for some time.
Bent Life History of the Glaucous-winged Gull
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 Glaucous-winged Gull – the common name and sub-species reflect the nomenclature in use at the time the description was written.
LARUS GLAUCESCENS (Nanmann)HABITS
This, the most abundant, the most widely distributed, and the characteristic gull of the north Pacific coast, is an omnipresent and familiar sight to the travelers along the picturesque coast and through the numerous inside passages leading to Alaska. From the coast of Oregon southward it is replaced by the dark-mantled western gull during the breeding season, and in Bering Sea it mingles with the large white Arctic species, the glaucous gull, by which it is replaced northward. During the latter part of April, in 1911, we first became familiar with the glaucous-winged gull in Puget Sound, where it was very abundant, feeding with the herring gull in large numbers about the harbors. As we steamed northward in May through various channels and sounds to Ketchikan, Alaska, the grand and picturesque scenery of those inside passages was enlivened and made more attractive by the constant presence of these gulls following the ship, drifting northward to their breeding grounds, or merely wandering in search of food. At Ketehikan they were particularly abundant in a great variety of plumages of different ages. But when we passed through Dixon Entrance and out into the Pacific Ocean we left the gulls behind, as the land faded away from sight, and when 50 or 100 miles from land they had been replaced by the more pelagic fulmars and albatrosses. We did not see them again until we came within sight of the Aleutian Islands, and from that time on they were always with us throughout the whole length of the Aleutian chain.
Spring: As this gull is practically resident, or, at least, always briefly a few typical breeding colonies in different localities. present throughout all but the extreme northern portions of its breeding range, it is difficult to tell just when it arrived on its breeding grounds; but it usually begins to frequent or to resent intrusion upon its nesting grounds at least a fortnight before egg laying begins, the dates varying greatly in the different latitudes. To illustrate the wide variations in its nesting habits I propose to describe:
Nesting: The largest and most interesting colonies of the glaucous-winged gull, in the southern part of its range, are among the spectacular sea-bird colonies on the rocky islands set apart as reservations off the coast of Washington, and divided into three groups, known as the Copalis Rock Reservation, the Quillayute Needle Reservation, and the Flattery Rocks Reservation. Mr. W. Leon Dawson (1908a) and Prof. Lynds Jones visited the various islands in these groups in 1905 and 1907, and made careful estimates of the numbers and kinds of birds found breeding there. The full report is well worth reading to gain a fair impression of what these wonderful reservations contain, but I shall confine my quotations to a few striking facts taken from it. Only two pairs of glaucous-winged gulls were found nesting on Destruction Island, which seems to be the southern limit of its breeding range. Thence northward, colonies of this species became more frequent and increased in size. The largest colony was found on Wishalooth Island, from 2,000 to 3,000 glaucous-winged gulls, 100 to 500 western gulls, 1,000 tufted puffins, 5,000 to 15,000 Kaeding’s petrels, and 100 Baird’s cormorants. This is an island of about 20 acres, three-quarters of a mile offshore in the Quillayute Needles Reservation. It is “a lofty jagged ridge of metamorphic conglomerate with sharply sloping sides covered with guano ledges and resulting areas of shallow earth, which are clothed with grass and other vegetation – yarrow, painted cup, and the like; 175 feet high; 200 yards long along the crest.” Carroll Islet, “the gem of the Olympiades,” as Mr. Dawson calls it, contained the following wonderful colonies of breeding water birds: Five thousand tufted puffins, 1,000 Cassin’s auklets, 20 pigeon guillemots, 700 California murres, 1,000 glaucous-winged gulls, 50 western gulls, 500 Kaeding petrels, 100 white-crested cormorants, and 500 Baird’s cormorants. Professor Jones (1908) has well described it, as follows:
Seaward Carroll Islet presents a rock precipice some 200 feet In height. A stone dropped from the top, within 2 rods of our camp, would fall clear into the ocean below. Landward the Islet slopes at first gently, but finally at an angle of nearly 70 to within 80 feet of the water, ending in another precipice there. It was only along the lnndward side that ascent was possible, and even there one must clamber up vertically for 10 or more feet, finding foothold in the weathered rock. Two sharp rock ridges jut out, one at the northeast corner, the other landward easterly. The gentler slope of the top is covered with Sitka spruce trees, two of them old monarchs, with a few deciduous trees, growths of elder bushes, a sort of red raspberry bush, and the ever-present salal bushes. Bordering on the steeper slopes there Is a growth of grass clinging to masses of soil which has lodged In the interstices between rock chips. In some places this grass is seen clinging to shelves on the face of precipices. Exposed rock faces are pitted and hollowed by the elements Into nesting places for cormorants and gulls. Other rock masses, a good deal worn down, project from the other angles of the island. The waves have worn a hole completely through the Island parallel to the landward side and about a hundred feet from it. Practically the entire island was covered by the nests of this species, except the area covered by the taller frees, and also a relatively small area on the steep slope of the northeastward side.
By covered is meant that there were nests In all sorts of situations and within reasonable distance of each other, but never within striking distance of the birds occupying adjoining nests. A number of nests were found beneath the dense fringe of salal bushes, and many of the larger grottoes of the perpendicular rock faces contained a nest. Ledges, which were broad enough to afford us secure footing, were also occupied by nests. Often nests could be seen on small niches in the rocks. There was one nest on the murre ledge fully exposed on the bare rock. Many of the more exposed nests showed unmistakable signs of having been pilfered by crows.
Professor Jones noticed that all of the gulls which were nesting under the bushes were old birds with pure white heads, while many of those nesting in the open showed signs of immaturity. The nests were also better made than those in the open.
We found this species nesting under somewhat different conditions in the Aleutian and Pribiof Islands, where it was decidedly the commonest large gull and universally distributed. On Bogoslof Island on July 4, 1911, we found a colony of between 100 and 200 pairs of glaucous-winged gulls nesting on the flat sandy portions of the famous old volcano. The steep, rocky pinnacles in the center of the island were densely populated by countless thousands of Pallas’s murres. Recent eruptions had thrown up so much volcanic dust, ashes, and sand that extensive sand dunes and flat sandy plains had been formed all around the island, which was entirely bare of shelter and devoid of vegetation. The nests of the glaucous-winged gulls were widely scattered over this area, no two being anywhere near together. They were well made of seaweed, rockweed, kelp, and straws, and were sometimes decorated with feathers or fish bones; some of the nesting material must have been carried a long distance, for the nearest land on which any grass was growing was many miles away. Many of the eggs were pipped and there were quite a number of downy young running about, but a few of the eggs were only slightly incubated. The nesting grounds of the gulls were closely adjacent to a large breeding rookery of Steller’s sea lions (Eumeto pins stelleri), with which they seemed to be on friendly terms.
A few days later we landed on Walrus Island, the most wonderful bird island in North America. Here we found a breeding colony of this species mixed with glaucous gulls on the highest part of the island, where the accumulations of guano had formed a rich soil, supporting a luxuriant growth of grass. Other portions of the little island, which I have described more fully in the history of the redfaced cormorant, contained, in close proximity to the gulls, the most densely populated colonies I have ever seen of California and Ipallas’s murres, tufted puffin, paroquet, crested and least auklets, Pacific kittiwakes, and red-faced cormorants. At the time of our visit (July 7, 1911) most of the gulls’ eggs had hatched, but a few eggs were still to be seen in the nests among the tufts of grass. Mr. William Palmer (1899) says of the nests on these islands:
On Walrus Island the nests are quite numerous. On June 13 many contained three eggs well Incubated; some had two fresh eggs, while a few had one or two young and an egg or two. Larger young were picked up on the rocks near the nests. The nests are well made, clean, and are generally composed of dead grass stems, which the birds bring from St. Paul. While most were placed on the flat rock, a few were in depressions of the sand which filled some of the larger crevices of the rocks.
Dr. E. W. Nelson (1887) says:
The usual nesting places of this species are the faces of rugged cliffs, at whose base the waves are continually breaking and the coast exposes its wildest and most broken outline.
He seems to think that instances of these gulls nesting in other situations are exceptional. They nest on the steep, rocky cliffs of St. George Island and in similar situations elsewhere, but they also nest frequently on the fiat, grassy tops of many small islands, and are found on the sandy plains of Bogoslof Island. We never found them nesting on the larger islands in the Aleutian chain, where they might be disturbed by foxes. On June 19, 1911, I saw a large number of glaucous-winged gulls frequenting a high grassy plain on Kiska Island and acting as if they were breeding in the vicinity, but I could not find any nests.
Eggs: The glaucous-winged gull normally lays three eggs, though frequently two constitute a full set; four eggs are very rarely, if ever, laid by one bird. Only one brood is raised in a season. The eggs are not distinguishable from those of other species of gulls of similar size. The prevailing shape is ovate, with variations toward short ovate on one hand and elliptical ovate on the other. The shell is thin and finely granulated, with only a dull luster. The ground color shows various shades of buff, “olive buff,” and pale olive. The eggs are spotted, generally uniformly over the entire surface, with small spots or occasional larger blotches of “wood brown,” ‘ raw umber,” “burnt umber,” or ” seal brown,” and with underlying spots of “lilac gray.” The measurements of 47 eggs in the United States National Museum average 72.8 by 50.8 millimeters; the eggs showing the four extremes measure 82 by 51.5, 73.5 by 55, 66 by 47.5 and 70.5 by 46.5 millimeters.
Young: Mr. George Willett (1912) noted the following incident in the education of the young:
I was considerably interested in observing the swimming lessons given the nearly grown young by the adult birds. In some cases, where the young seemed afraid to take to the water, they were shoved from the rocks by the old birds. The old bird would then swim beside the young one, occasionally poking It with her bill. I was unable to satisfy myself whether this was meant as a caress or as punishment for poor swimming.
Plumages: The period of incubation does not seem to be definitely known. The downy young is “drab gray” above, variegated with “avellaneous,” and a paler shade of the same color below, fading to “tilleul buff” on the center of the breast. It is heavily spotted on the back with” fuscous black ” and on the head and throat with pure black. The young birds somewhat resemble those of the western gull, but the latter has more of the buffy shades and less of the gray; and the markings on the back are not quite so heavy. Perhaps in large series they might intergrade.
Dr. Jonathan Dwight (1906) has fully described the sequence of plumages in this species as follows:
The juvenal plumage Is deep plumbeous gray with broad dark barring or mottling and obscure whitish edgings. The tall is nearly solidly gray, sprinkled basally with white, and the flight feathers, including the quills, are also dark gray. Birds in this plumage are never so pale (especially the primaries) as the darkest leacopteras, nor are they ever so dark as the palest of the blackprimarled species. They fade to a decidedly brown shade, almost mouse gray, but their color (especially that of the primaries) and the size of their bills, even when young birds, are cardinal points by which to recognize them. The first winter plumage is like the juvenal, but at the prenuptial molt white about the head and body and gray on the back begins to appear in some spedmetis, thus marking the first nuptial plumage. In the second winter plumage unpatterned drab or mouse-gray primaries are most frequent, together with the gray mantle of the adult. The white head and neck, as In the other species, are much clouded with dusky markings, which are lost at the next prenuptial molt. I do not think that primaries with the apical white spots of the adult bird are ever developed until a year later, but in some birds there is a foreshadowing of the white spots on the first primary. The third winter plumage, that of the adult, is the result of the second post-nuptial molt, after which very few birds can be found showing traces of immaturity. The new primaries are slaty, and white tipped, the first and sometimes the second with subapical or sometimes terminal white “mirrors,” quite unlike the unpatterned feathers of glaucua or the smaller tencopterus. The mantle varies from cinereous to plumbeous gray, the color running over into the primaries, which become decidedly slaty toward their apices. The white of the head and neck Is still clouded, the dusky markings being characteristic of winter plumages until the birds are quite advanced in age. At prenuptial molts, as In the other species, these feathers are replaced by white ones.
Food: These, like other large gulls, are useful scavengers all along the coast and are practically omnivorous. They were constantly following our ship in search of small scraps that might be picked up, and, while we were at anchor at Ketchikan and Unalaska, they were especially numerous and always in sight, eagerly waiting for the garbage to be thrown overboard. They are abundant, in winter, in the harbors of nearly all the large cities on the Pacific coast as far south as southern California, where they feed largely on refuse and seem to fill the place occupied by the herring gull on the Atlantic coast. They are particularly numerous about the garbage heaps which are dumped on the shore to be washed away by the advancing tides. In such places they appear to realize that they are protected and are very tame. In their eagerness to secure the choice morsels of food they seem to forget all about the presence of human beings, even within a few feet. At other times it is difficult for a man to walk up within gunshot distance of them. They become much excited and clamorous in their scramble for food, competing at close quarters with other species of gulls, with dogs, and with the lazy Indians. They are none too particular in their choice of food and will eat almost anything that is edible.
During the summer they frequent the vicinity of the salmon canneries, where they gorge themselves on the refuse from the factories or fishing vessels and on the bodies of dead salmon along the shores. As a result they become very fat. On the Pribilof Islands they regularly visit the killing grounds to feast on the entrails and other waste portions of the slaughtered seals, which furnish an abundant food supply. Among the Aleutian Islands, where sea urchins are abundant, we found numerous broken shells of these creatures on the rocky heights frequented by the gulls. Evidently they had been dropped on the rocks to break the shells. In the colonies, where they were nesting with other species, we saw no evidence to prove that they feed on the eggs or young of their neighbors, though they may, perhaps, do so occasionally. On Walrus Island we kept some of the murres and cormorants off their nests for several hours without any apparent damage from the gulls.
Behavior: The flight of the glaucous-winged gull is buoyant, graceful, and pleasing, and its plumage is always spotlessly clean and neat. A gull in flight is one of nature’s most beautiful creatures and one of its triumphs in the mastery of the air. It was a neverending source of delight to watch these graceful birds following the ship at full speed without the slightest effort, dropping astern to pick up some fallen morsel or forging ahead at will, as if merely playing with their powers of flight. Sometimes the same individual could be recognized day after day by some peculiarity of marking. They seem thoroughly at ease on the wing. Several times I saw one scratch its head with its foot, as it sailed along on set wings, without slackening its pace at all. When traveling against a strong head wind I have seen one sail along for miles without moving its wings, except to adjust slightly the angle at which they were held, keeping alongside the ship, forging ahead, or dropping astern, as it wished, and rising or falling to suit its fancy. When left far astern to pick up food off the water it would give a few flaps when rising, set its wings, and soon catch up with the ship. This power to sail almost directly into the teeth of a strong wind has caused much discussion, as it has been noted in the herring gull and other species. Various theories have been advanced to account for it, all of which are more or less unsatisfactory. To my mind it is simple enough to understand if we can realize that a gull is a highly specialized, almost perfect sailing vessel, endowed with instinctive skill in navigating the air to use the forces at its command to advantage. With a clear knowledge of the forces at work when a ship sails, close hauled, to within a few points of the wind, we can imagine the gull sailing along a vertical plane, in which the force of gravity replaces the resistance of the water against the keel and the wind acts against the gull’s wings as it does on the sails of the ship; the resultant of these two forces is a forward movement, which the gull controls by adjusting its center of gravity and the angle of its wings.
It is evident from the foregoing accounts that the glaucous-winged gull is decidedly a sociable species on its breeding grounds where it seems to nest in perfect harmony with its neighbors in close quarters. It also associates on migrations and during the winter with various other species of gulls, with all of which it seems to be on good terms. The adults can readily be distinguished from the white-winged species or from those having black-tipped wings by the peculiar color pattern of the primaries. Birds in immature plumage are not so easily recognized, but a careful study of the descriptions given in the manuals will help to identify them. They are not likely to be confused with the dark-mantled western gull, but Mr. Dawson’s (1908) reference to the large number of “mulattoes” on Carroll Islet suggests the possibility that these two species may hybridize.
Mr. Dawson (1909), who spent a week studying the vocal performances of this species and their significance, has thus classified its various notes:
1. The beak-quaking notes – Harsh, unmusical, and of moderate pitch, used to express distrust and continued disapproval. During the delivery the mandibles are brought together three or four times in moderate succession. This is the ordinary scolding or distress cry of characteristic and uniform pitch, save that it is raised to a higher key when the speaker becomes vehement. The phrase varies from three to five notes, and is uttered in the following cadences: kak–ako; ka ka. ka ka; ka ka kaka; kaka; kaka, ka kakak; kak-a kak-a-ka.
2. Kawk: A note of Inquiry or mere communication; has many modifications and varies from a short trumpet note to the succeeding.
3. Klookó – A sepulchral note of uniform interest but uncertain meaning.
4. The trumpet notes, long or short, single or in prolonged succession, highpitched, musical, and far-sounding. During delivery the head is thrust forward, the neck arched, and the throat and mandibles opened to their fullest capacity. These are pleasure notes and are used especially on social occasions, when many birds are about, kear, keer, keer, keer.
5. A(n)k, a(a)k, a(n)k, a(n)k, a(a)k, a(a)k: Mlnor trumpet notes of regular length and succession, used in expostulation or social excitement; frequent and varied.
6. Klook, klook, klook: Ia quality a combination of kawk and the trumpet tones, uttered deliberately and without much show of energy. Used chiefly in domestic conversation of uncertain import.
7. Ot-ee-ek, oree-ek, oree-eh, an an an: An expression of greeting as when uttered by a sitting bird welcoming one about to alight. The notes of the flu-st series are trumpet tones, in which the second syllable of each member is raised to a hIgher pitch, whIle the voice is dropped again on the third. The second serIes is lower and more trivial, but stIll enthusiastic, as though congratulatory to the guest arrived.
8. Ko: Shouted once, or thrice repeated, in quelling a clamor. “Hist! Hist I You’re making too much noise; he’s watching us.”:
9. Arahh: A slow and mournful trumpeting, usually uttcred awing, to express anxiety or grief, as at the loss of a chick.
10. Oo anli, 00 anh: Repeated indefinitely. Notes of coaxing and endearment usually addressed to children, hut occasionally to wedded mates. The cooing of doves does not express so touch adulation or idolatrous devotion as the gull throws into these most domestic tones.
Winter: When winter, with its snow and ice, drives the glaucous-winged gull from the northern portion of its breeding range, there is a general movement southward; but the migration is more in evidence along the California coast, where this species spends the winter in large numbers, frequenting the harbors in company with glaucous, herring, California, western, and short-billed gulls. It winters commonly as far north as the Aleutian Islands, where it can always find open water.
Breeding range: Coasts and islands of the North Pacific Ocean and Bering Sea, from St. Lawrence Island and the Pribilof Islands southward to southern Alaska, British Columbia, and Washington to Destruction Island; westward throughout the Aleutian and Commander Islands; northward to Kamchatka and northeastern Siberia (Providence Bay). Occurs rarely in summer in northern Bering Sea (St. Michael and Port Clarence), but probably does not breed there.
Breeding grounds protected in the following national reservations: In Alaska, Aleutian Islands, as Adak, Atka, Attu, Kiska, Tanaga, and Unalaska; Bogoslof; St. Lazaria; Forrester Island; in Washington, Flattery Rocks and Quillayute Needles, as Alexander Island, Carroll Islet, and Destruction Island.
Winter range: From the Aleutian Islands, Kodiak, and southern Alaskan coast southward to lower California (San Geronimo and Guadalupe Islands), and from the Commander Islands to Japan (Hakodadi). Birds remains late at the Pribilof Islands, but probably rarely, if ever, stay throughout the entire winter.
Spring migration: Northward along the coast. Late date of departure: Lower California, San Geronimo Island, March 10 to 15, and Guadalupe Island, March 22; California, Santa Crus Island, May 2, and Monterey, May 10.
Fall migration: Southward along the coast. First arrivals reach California, Monterey, October 25 to 30.
Casual records: Rare visitor to Hawaii (taken December 9, 1902). Rare straggler north of Bering Strait; taken in Kotzebue Sound May 11, 1899, on Wrangel Island April 3, 1916, and at Point Barrow September 19, 1882.
Egg dates: Alaska, south of peninsula: Fifty records, June 3 to July 16; twenty-five records, June 20 to July 3. Washington: Nineteen records, May 29 to July 23; ten records, June 14 to 19. British Columbia: Sixteen records, June 14 to July 16; eight records, June 16 to 24.