Gyrfalcon

The Gyrfalcon is the world’s largest falcon, and ranges from nearly completely white to dark gray to brown above with a variable amount of horizontal barring or dark streaking on the underparts.  Length: 22 in.  Wingspan: 47 in.

-Sexes similar.

None.

Similar to adults, may show darker wing linings combined with lighter flight feathers.

Tundra, coastal areas, and mountains.

Mainly birds.

Forages mainly by capturing prey in flight.

Breeds in arctic regions and winters as far south as the northern U.S., with occasional bird turning up much farther south in fall migration and winter.

More information:

Bent Life History

Visit the Bent Life History for extensive additional information on the Gyrfalcon.

Wing Shape

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.

• Male, adult, Washington, Mar.
• From below

Wing images from the University of Puget Sound, Slater Museum of Natural History

Male Gyrfalcons only weigh about 65% as much as females.

When defending a territory, Gyrfalcons will chase ravens, eagles, hawks, and owls.

The most common call consists of a repeated “kak-kak-kak”.

The nest is placed on a bare ledge or in an old tree nest.

Number: 3-4.
Color: White with darker markings.

Incubation and fledging:
– Young hatch at 35 days.
– Young fledge (leave the nest) in 45-50 days after hatching but remain with the adults for some time.

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 Gyrfalcon – the common name and sub-species reflect the nomenclature in use at the time the description was written.

The gyrfalcons have always been a very puzzling group; their nomenclature has been confusing, their relationships have never been well understood, and confusion as to the distribution of the different forms has been even worse. Various views on all these points have been expressed by different writers, but none of them are conclusive or wholly satisfactory. Until we have available a considerable series of breeding birds, both adults and their young, collected in various parts of the breeding ranges, we shall never fully understand the relationships of the various forms and their ranges. Most of the specimens in collections are late fall or winter birds, which may have wandered far from their native ranges. Even summer specimens are not necessarily breeding birds, as immature birds and non breeding adults are often widely scattered in summer. We need also a series of young birds in juvenal plumage, taken before, or soon after, the flight stage is reached, to help us recognize with certainty the immature plumages of the different races.

At one time the white gyrfalcons of northern Greenland were considered as specifically distinct from the gray forms, but it now seems to be generally conceded that all the forms are races of one species, Falco rusticolus. The British Ornithologists’ Union List (1915) recognizes two species, Hierofalco gyrfalco and H. islandus, each with two subspecies, only three of the four forms being listed as British. But Witherby’s Handbook (1924) includes the three British forms as subspecies under rusticolus, Peters’s Check-List (1931) names five races from different parts of the world, all as subspecies of rusticolus. Only three of these are, included as North American in the latest American Ornithologists’ Union Check-List (1931). I examined the large series of specimens in the Museum of Comparative Zoology, on which Mr. Peters based his conclusions, and I believe his treatment of the group is as nearly correct as our present knowledge permits.

The distribution given in the A. 0. U. Check-List (1931), which is practically the same as that given by Peters (1931), is, I believe, substantially correct, but I doubt if candicans breeds regularly anywhere on the North American Continent; the Asiatic form, uralensis, very likely does extend its breeding range into extreme northern Alaska but probably not onto the southern Bering Sea coast. Apparently all the gyrfalcons that breed regularly on the North American mainland are referable to obsoletus. The breeding records of the white gyrfalcons in Labrador and Ungava, mentioned below, doubtless represent cases of casual breeding far south of the normal breeding range.

The white gyrfalcon (Falco rusticolus candicans) breeds in northern Greenland at least as far south as latitude 760 N. and perhaps farther on the west coast; on the east coast it may breed farther south than on the west coast, as the east coast is much colder. In southern Greenland, at least from Disco Island southward, the breeding birds are darker, but just what their status is has not yet been definitely determined. Dr. Walter Koelz (1929), who went to Greenland on one of the MacMillan expeditions, brought back a fine series of these falcons; these are deposited in the University of Michigan collection, which now contains 88 Greenland gyrfalcons. In this large series he found specimens from various points in southern Greenland, from latitude 730 southward on the west coast, which compare favorably with the Iceland bird (islandus), with the Scandinavian bird (rusticolus), and with the dark North American bird (obsoletus). These puzzling variations are probably due to interbreeding with birds from Labrador, or possibly from Iceland. Such strong-flying and wide-ranging birds could easily fly from either of these places to Greenland and might become established there. Ptarmigans regularly migrate between Greenland and Labrador, and the short distance could easily be covered by a gyrfalcon. It is conceivable that obsoletus, the dark Labrador race, might regularly migrate to southern Greenland and, by interbreeding with the light northern race, produce a variety of intermediates.

Dr. Frank M. Chapman’s (1899) study of a collection of 33 gyrfalcons from Greenland shows much the same range of variation from the lightest to the darkest forms. He says: “Four examples are dark enough to be referred to F. it obsoletus, one of them being fully as dark as the darkest of three specimens from Ungava, Labrador kindly loaned me by Mr. Ridgway, and warrant the addition of Falco rusticolus obsoletus to the Greenland fauna. These birds are connected with the lighter specimens in the series by finely graded stages.”

Nesting: First-hand, reliable information on the nesting habits of the white gyrfalcon is very scanty. A. L. V. Manniche (1910) found five nests in northeastern Greenland, where candicans proved to be the breeding form. He writes:

I only succeeded in making relatively few observations regarding the breeding of the Gyrfalcon. Only one of the nests found was accessible viz, that on Nordre Orienterings.

May 19th 1907 I shot an old female at this nest; judging from her exterior she must have been sick, certainly from an inflammation of her oviduct. In her ovary were found 5 rather developed eggs. She had very pale plumage and orange-yellow feet. In the nest was lying a fresh egg, which on one side had a crack caused by frost. Like the other eyries observed, this one was conspicuously marked by heaps of excrements and remnants from the meals of the birds such as pellets, bones and other remains of animals. It was placed only 10 meters above the level of the sea on the northern side of the rock, which rises precipitously and steeply from the Stormbugt.

Judging from the enormous heaps of excrements the nest had certainly been inhabited for many years. The bottom of the nest was formed only by the excrements of the birds.

A falcon flying out from this nest was observed July 14th in the same year, so the male must within a short time have found another mate.

The next spring the female falcon was observed at the nest already April 20th. The breeding did, however, not commence before May 26th.

I often passed the nest end thus had good opportunity to observe the breeding falcon.

She kept very close to the nest, and did not leave it, even if I approached to the very side of the rock, only stretching out her neck to eye me anxiously. The male used to sit on the projections not far from the nest.

June 22nd I arrived together with two of my companions in a dogsledge at the eyrie of the falcon, intending to secure the young ones now supposed to be hatched.

The 4 eggs were, however, not yet hatched, but I could plainly hear the hoarse cries of the young ones within. The shells were still unbroken with exception of one, that had an insignificant crack. I kept the eggs warm by putting them under my shirt against my body.

Having sledged for some hours we arrived at my station at Stormkap, and here I continued my brooding of the eggs in my sleeping-bag.

The first of the young ones emerged on June 23rd the next three 24 hours later. The time of incubation for this clutch of eggs was thus nearly 29 days.

The female Falcon behaved very anxiously when I ascended the rock and she very unwillingly left her nest. Several times she rushed swiftly and vigorously towards the disturber. The male, which proved very cautious, left the rock, when the female was shot.

* * * June 8th 1908 I found another nest of Gyrfalcon on the steep northern side of the mountain Trekroner. This nest was placed at least 200 meters over the level of the ground and was quite inaccessible.

The enormously high heaps of excrements around the nest formed a large whitish-yellow ledge and could he seen from a distance of 3 km. Around the eyrie a colony of Barnacles (Anser leucopsis) had their nesting places. I was surprised to see, that the Geese were sitting in couples on the projections close to the Falcons.

When I: by means of a pair of rifle bullets: caused the breeding falcon -to fly out of her nest, she and the male circled around the mountain in company with the Geese for a long while. From a dizzy height the falcon at last swift as an arrow shot down to the nest and was soon followed by the Barnacles, which again confidently took their seat close by.

This eyrie also looked as if it had been used from immemorial time.

Falcons eyries were also recorded on the high rock Teufelkap and on a rock near the M0rkefjord; both of them were: like the two already mentioned nests: built on the northern side of the mountains. This was also the case with the 5th nest of a bird of prey, which was found, and which certainly also belonged to a Gyrfalcon.

This can hardly be considered accidental; perhaps the falcons choose to nest on places, which in the coldest time of the day and night are warmed by the midnight sun; it must be remembered, that the breeding-time is partly in May, in which month the temperature of the nights is usually some degrees under zero.

Lucien M. Turner, in his unpublished notes, records the nesting of a pair of white gyrfalcons in northern Ungava, as follows:

A pair was building their nest on the side of the bluff known as Hawk’s Head, some two miles north of Fort Chimo. I undertook to ascend the bluff by means of a rope drawing me up a distance of 168 feet, where I had nothing to cling to but the rope and be whirled round and round dozens of times (as the nest was on a part which could not be reached from above) until, when I reached the spot where the nest was located, I was so dizzy that I was glad to find a resting place; and, when I attained the site, I put my foot directly on the half completed nest, composed of a few sticks and a great quantity of dry grass, forming a bulk about 15 inches across the top and 3 inches high. The birds were whirling and screaming off at a distance while a man was firing at them. The birds deserted the locality and were not seen again.

Audubon’s (1840) account of the finding of a nest of white gyrfalcons near Bras d’Or on the southern coast of Labrador on August 6, 1833, seems worthy of credence. Both parent birds were shot at the nest, and his drawing, made on the spot, is unmistakable. As this is far south of the present known breeding range, it must have been a very exceptional case. He describes the nest as follows:

The nest of these hawks was placed on the rocks, about fifty feet from their summit, and more than a hundred from their base. Two other birds of the same species, and apparently in the same plumage, now left their eyrie in the cliff, and flew off. The party having ascended by a circuitous and dangerous route, contrived to obtain a view of the nest, which, however, was empty. It was composed of sticks, sea-weeds, and mosses, about two feet in diameter, and almost fiat. About its edges were strewed the remains of their food, and beneath, on the margin of the stream, lay a quantity of wings of the Uria Troile, Mormon articus, and Tetrao Saliceti, together with large pellets composed of fur, bones, and various substances.

Eggs: The white gyrfalcon lays ordinarily four or five eggs; these are indistinguishable from those of the other races of the species, which are described under obsoletus. The measurements of 90 eggs average 58.7 by 45.7 millimeters; the eggs showing the four extremes measure 64.4 by 50.8, 53.5 by 44.5, and 56.9 by 41.4 millimeters.

Plumages: I have never seen the downy young of this falcon and doubt if there are any anywhere in American collections. This race is easily recognized at any age, as it is always much whiter than any of the other gyrfalcons. Dr. Koelz (1929) describes two nestlings, which were still in the nest but fully feathered, as follows:

The under parts are entirely white with a creamy cast, except for a band of narrow streaking of brown on the feathers of the breast (the male specimen has only the sides of the breast streaked), and broader streaks of the same color on the feathers of the sides. The under tail coverts and the tarsals are immaculate. The general tone is white above. The top and the sides of the head are faintly lined along the feather shafts with dark brown. The feathers of the back have a streak of brown along the shaft of the feathers, which broadens as it nears the tip to become rather pendant shaped. On the shortest scapulars the drop becomes broader so that the feathers here may he described as brown with a broad border of white. The upper tail coverts are streaked like the breast. The tail feathers are pure white. The wing coverts are marked about like the scapulars; the short ones with a central field of brown and the longest ones with broken v-shaped crossbars. The wing feathers are white with dark shafts and a few broken bands of dark brown, chiefly near the tips.

The two nestlings, described above, came from Etali in northern Greenland. Of an adult candicans, also from northern Greenland, he says:

The adult has the entire under parts immaculate. ‘The back is chiefly white. The crown, sides of head, and fore part of the hack are unspotted except for a few lines of black brown on the ear coverts and on a few feathers of the occiput. The upper tail coverts, the rest of the back, and the wing coverts are barred with arrow shaped blotches of black brown. The tail is virtually pure white. The plumages of adult and juvenile are thus different. Young birds have the markings paler, probably more numerous, and they tend to run lengthwise of the feather, especially on the short feathers.

Specimens from farther south in Greenland, both juvenals and adults, are darker, showing resemblances to corresponding plumages of islandus, rusticolus, or even obsoletus. These are, of course, not true candicans and have probably been produced by interbreeding with the dark birds from Labrador. Hagerup (1891) says that “Holboll and Fencker repeatedly observed mated pairs, one of which was white (F. isiandicus), and the other dark (F. ru.sticolus)” and that “Holboll also found light and dark colored young in the same nest.” The latter is just what might be expected, as a result of the former, under the well-known laws of heredity.

The juvenal plumage is worn for a year or more and then gradually molted between June and January. This new plumage is practically adult. Mr. Turner says that subsequent plumage changes are much like “those of the snowy owl and extremely old birds become pure white with the exception of the tips of the wings.~~

Food: The two species of ptarmigans seem to furnish the principal food supply of this gyrfalcon, especially in winter, when they are about the only birds available in the far north. Mr. Turner says that at Fort Chimo it is called the “partridge hawk” by the English speaking people, who apply the name of “partridge” to both ptarmigans and to the spruce grouse. Manniche (1910) says that it feeds mainly on lemmings in northeastern Greenland, as well as on various birds and occasionally on the Alpine hare. When springtime brings the hosts of summer birds to the Arctic shores, the falcons feast and feed their young on the numerous sea birds, dovekies, puffins, murres, guillemots, and kittiwakes. They are even strong enough to kill the eiders and other ducks and geese. The smaller land birds and shorebirds are less often taken, but golden end ringed plovers, phalaropes, snipes, turnstones, dunlins, purple sandpipers, and snow buntings have been recorded in their food.

Manniche (1910) writes:

The falcons appeared most numerously near the ship to which they were allured by the pigeons of the expedition. From September 3rd to 17th 17 falcons were shot here. Often 4 to .5 individuals would appear at one time either circling around the mast-heads, on which they sometimes settled, or sitting around on the surrounding hummocks of ice or blocks of stone, watching for pigeons.

As soon as these were started in the air, they wore most violently pursued by one or several falcons which, however, never succeeded in capturing a pigeon.

I often saw a falcon and a pigeon maneuvering for a long while extremely high up in the air until the pigeon finally: swift as an arrow: vertically shot clown to the ship and entered the pigeon-house, which was built on the deck, all the while pursued by the falcon, which stretching its talons forward and uttering angry cries would only give up the chase just before the entrance-hole of the pigeon house. During this autumn 10 falcons were shot: all of them young birds, and at least 5 times as many were seen.

During its winter wanderings this falcon preys on the native grouse, and sometimes attacks domestic poultry. Elsie Cassells (1922) reports that “a fine specimen of the White Gyrfalcon was shot by Mr. Waghorn on his farm at Blackfalds, Alberta, in the act of attacking one of his turkeys in December, 1920.” M. J. Magee (1932) refers to two cases of its eating prairie chicken s; in one case “the bird had subside it 140 grams of Prairie Chicken, meat, bones and feathers.”

Behavior: There seems to be no great admiration among observers for the swiftness and skill of the gyrfalcon in capturing its prey in flight. The foregoing statement by Manniche (1910) would seem to indicate that the pigeons were more than a match for it. Hagerup (1891) had a similar experience; he flew his pigeons regularly to attract gyrfalcons but never lost a pigeon. Manniche (1910) also says that a gyrfalcon cannot catch a phalarope on the wing. Kumlien (1879) says: “I often had an opportunity of witnessing this hawk preying upon jaegers, kittiwakes, &c., but was surprised that they are not possessed of swifter flight. A duck hawk would have made a short job of catching a kittiwake that one of these hawks followed till he fairly tired the bird out. Their success seems to depend more upon a stubborn perseverance than alacrity of flight.”

Audubon (1840) writes:

Their flight resembled that of the Peregrine Falcon, but was more elevated, majestic, and rapid. They rarely sailed when travelling to and fro, hut used a constant beat of their wings. When over the Puffins, and high in the air, they would hover almost motionless, as if watching the proper moment to close their pinions, and when that arrived, they would descend almost perpendicularly on their unsuspecting victims.

Their cries also resembled those of the Peregrine Falcon, being loud, shrill, and piercing. Now and then they would alight on some of the high stakes placed on the shore as beacons to the fishermen who visit the coast, and stand for a few minutes, not erect like most other Hawks, but in the position of a Lestris or Tern, after which they would resume their avocations, and pounce upon a Puffin, which they generally did while the poor bird was standing on the ground at the very entrance of its burrow, apparently quite unaware of the approach of its powerful enemy. The Puffin appeared to form no impediment to the flight of the Hawk, which merely shook itself after rising in the air, as if to arrange its plumage, as the Fish Hawk does when it has emerged from the water with a fish in its talons.

Turner says, in his notes: “The manner of flight is by rapid beats of the wings followed by a short sail. They dart with astounding swiftness among a flock of ptarmigans and seize them while the prey is flying or on the run. The hawk carries the bird to a convenient spot to be devoured; or oftentimes consumes it where it was taken. This depends on the particular location, which, if commanding a good view, the falcon will not carry the food, but, if it is in a low spot, the ptarmigan is usually carried to higher ground. I have never seen this hawk alight in trees, always on the earth.”

Dr. W. Elmer Ekblaw thus describes, in his notes, an attack on a glaucous gull by a pair of white gyrfalcons, probably in an attempt to drive the gull away from the vicinity of their nest:

The big gull seemed much harassed. While I watched he appeared to become fatigued and more vulnerable to the attack. At first he evaded every stoop the falcons made, either by rising to meet them or by suddenly dodging. He would fly fast and strong in a straight line and then suddenly, as the hawks caught up with him and gained the advantage by being above him, he would double abruptly on his course while the falcons, apparently not able to alter the direction of their flight so quickly as lie, would lose both distance and advantage by sailing on by him. Whenever the hawks pounced down upon him, lie would rise quickly and obliquely to meet them, but at the last of the fight, as I saw it, he faded to meet them promptly as at first and they often succeeded in striking him about the head. Always as they did so, he screamed angrily and worriedly. The method of the attack of the falcons was to rise above him and dash or stoop down upon him from behind, first one striking him and then the other, and then rising above him again. Immediately after each strike they would give a piercing whistle.

Enemies: Manniche (1910) relates the following two incidents in which the gyrfalcons were attacked by other birds:

A falcon was in the most violent manner attacked by two Ravens. The quarreling birds flew for a while around high up in the air uttering angry cries, after which the Ravens descended and took place side by side on a rock evidently lurking after Lemmings, the holes of which were numerous around the place. The falcon also settled with the same intention on another rock some 50 meters from the Ravens. At my approach the birds rose again in the air and immediately continued their battle. The Ravens seemed much superior to the falcon, which therefore showed an inclination to fly away to avoid their rough treatment.

The battle at last took place just over my head, and I shot one Raven in order to make the fight more even.

Frightened by the shot the two other birds flew away in different directions, but they soon met again, and took up the battle nearer to the coast. Here the falcon got relief from two birds of its own kin, and now the Raven was obliged to depart hastily, while the three falcons settled on the summit of a rock.

Not rarely I observed falcons pursued by Skuas (Lestris ton gicauda). At the end of August the young Skuas will frequently be sitting around on stones, still cared for by their parents, which with extreme violence will guard their offspring against attacks from falcons. The Skuas exceed by far the Gyrfalcons in ability of flight, and the falcons therefore always wish to escape the pursuit and retire to the rocks. Most frequently 3 or 4 Skuas would join in an attack; the battle would usually be fought out immensely high up in the air.

Field marks: This bird can be recognized as a falcon by its long pointed wings and its manner of flight, rapid wing beats with occasional short sailings, or a stationary, hovering flight. But only by its greater size can it be known as a gyrfalcon. If it has a wholly white breast and is mainly white above, it is an adult white gyrfalcon; even young birds of this race are nearly white below and largely white above. All other gyrfalcons are considerably mottled or streaked on the under parts and dark colored above. Gyrfalcons are not likely to be seen within the United States except in winter.

Winter: Some of the gyrfalcons remain far north throughout the winter, wherever they can find a sufficient food supply. But, as the ptarmigans migrate southward, many of the falcons have to follow them. White gyrfalcons are much commoner in winter than in summer in southern Greenland. Bernhard Hantzsch (1929), writing of northeastern Labrador, says:

It most probably does not breed until northward of our district, but reaches it occasionally as a visitor and migrant. The birds, especially in autumn, regularly follow the flights of the ptarmigan which make their favorite food. However, they feed upon everything else possible, apparently not only on living creatures. The inhabitants not seldom find thorn during the winter in the baited fox-traps, by which the birds become annoying to them. These more or less light winter visitors and migrants are far more frequent than the dark breeding birds; indeed, in many years of abundant snow they are said to occur in rather large numbers.

Mr. Turner says that this “bird is far more numerous from September to April than at other times” in Ungava. At this season it wanders far from its summer haunts in search of food, though only rarely to the southern Provinces of Canada and to the northern States.

DISTRIBUTION
Range: The species is circumpolar in its distribution and confined almost entirely to the Arctic and sub-Arctic regions, wandering irregularly south to the Northern United States, the British Isles, central Europe, and Kamchatka.

Breeding range: In North America the gyrfalcon breeds north to northern Alaska (Tuksuk River, Kotzebue Sound, Fort Yukon, Point Barrow, and the Porcupine River “above Fort Yukon”); Grinnell Land (Cape Hayes); and Greenland (Godhavn). East to Greenland (Godhavn, Holsteinborg, Frederikshaab, and Ivigtut). South to southern Greenland (Ivigtut); Labrador (Cape Chidley and Port Purnell); Ungava (Chimo); southern Franklin (Iglulik and Felix Harbor); northern Mackenzie (Fort Anderson); and Alaska (Crater Mountain). West to Alaska (Crater Mountain and Tuksuk River). The species also is reported to breed on the east coast of Greenland; for exact details see Manniche (1910).

Winter range: The precise limits of the winter range are difficult to define, as the gyrfalcon is resident in many high latitudes as in Alaska (Nulato), Ungava (Chimo), and Greenland. Its southward movements are always irregular, but based upon frequency of occurrence the winter range may be stated as south to Massachusetts (Ipswich, Northampton, and Meirose); Rhode Island (Providence, Tiverton, and Newport); Connecticut (Durham); New York (Fishers Island, Quogue, Oceanside, Flushing, Chester, Canandaigua, and Monroe County); Pennsylvania (Kittatinny Ridge and Manheim); southern Ontario (Ottawa); Wisconsin (Beaver Dam); Minnesota (Minneapolis and Madison); Montana (Shonkin and Fortine); and southern British Columbia (Saanich, mouth of the Fraser River, and Comox).

As above sketched the territory includes all races of the gyrfalcon that are found in North America, but, as has been previously indicated, the respective ranges are not clearly understood. Generally speaking, the typical North American race is the black gyrfalcon (Falco r. obsoletus), which is found from northern Alaska to Labrador, wandering southward to New England, Pennsylvania, the Dakotas, British Columbia, and, casually, even farther. The white gyrfalcon (F. r. candicans) is resident in Greenland and possibly also in extreme northeastern Canada. It too is known occasionally to wander south to the Northern United States. The Asiatic gyrfalcon (F. r. uralensis) is found in northern Siberia east to Kamchatka and the islands in Bering Sea. It has been recorded as breeding on the coast of Alaska (Deering, Kotzebue Sound, and Muller Bay).

Migration: Very little information is available concerning the movements of the gyrfalcons. In the fall of 1905 there appears to have been a rather extensive southern movement in both Europe and North America. It has been recorded that during the fall of 1908 they were abundant at Winter harbor, Franklin, and that the last one seen was on September 8. The Kittatinny Ridge in Pennsylvania is apparently a good observation post for this species, several having been noted there in the fall of 1934, from October 11 to November 2.

Nothing is known of the return trip to the north.

Casual records: There are several widely scattered records of occurrence south of the winter range above outlined. Among these are: Ohio, a specimen from Washington Court House on January 30, 1907; North Dakota, one collected at Grafton, on October 7,1908; South Dakota, one on October 21, 1880, near Vermillion; Kansas, one at Manhattan on December 1, 1880; Wyoming, one noted at Fort McKinney during the winter of 1883: 84; and Washington, a specimen collected near Spokane, in December 1890.

Egg dates: Greenland: 5 records, May 6 to June 13.

Arctic America: 6 records, May 9 to June 12. Labrador: 3 records, May 22 to 28.

BLACK GYRFALCON
FALCO RUSTICOLUS OBSOLETUS Gmelin
HABITS

This, the darkest of all the gyrfalcons, was formerly supposed to be confined to Labrador in the breeding season; but now it is generally conceded to be the dominant American form, breeding all across the northern part of the continent from Labrador to northern Alaska. Lucien M. Turner says in his unpublished notes on the birds of Ungava:

This species may be considered common, as it is the most abundant hawk in the region. During the excessively cold periods of winter but few are to be seen. About the middle of March they are more numerous, and they become plentiful by the last of April. They evidently retire to the southern portion of the region for the winter. AB soon as the warm days of April arrive these birds seek their mates and, from the evidence presented under the remarks on the eggs procured, it would seem that their courtship is of short duration. These hawks have no special preference for any particular portion of the country, whether it be barren or wooded.

Dr. E. W. Nelson (1887) says of its status in northern Alaska, though some of his notes may refer to uralensis: Throughout all Alaska, from the Aleutian Islands, north, both along the coast and through the interior, extending from Bering Straits across the northern portion of British America, the present falcon is the commonest resident bird of prey. It was observed by Murdoch at Point Barrow, though it was not common. It frequents the vicinity of cliffs and rocky points about the sea coast, or the rocky ravines of the interior, during the breeding season, and the remainder of the year, especially in fall, it is found wandering over the country everywhere that food can be obtained; it is especially numerous during the migration of the Ptarmigan along the sea-coast.

Nesting: -Mr. Turner’s notes contain the following account of a nest he examined near Fort Chimo, Ungava, on May 22, 1883:

The “Chapel” is an immense rock some 300 feet above the surrounding rocks, and gradually slopes upward to the north end, which is almost precipitous and absolutely inaccessible. The eastern side is more abrupt, being in places over 200 feet almost perpendicular. Here are several ledges on which these hawks have built their nests for many years. On April 7, 1883, I observed beneath the nest site first selected a number of sticks and other refuse lying on the snow below, as if the situation bad been subjected to a rearrangement or cleansing process; such material as appeared unnecessary was rejected and cast over the side of the ledge. The site of this nest was a narrow ledge of rock, which projected from the main wall and embraced an area of not over three superficial feet. Here was an accumulation of spruce and larch twigs and branches of various sizes imbedded in what appeared to be the accumulated debris of many generations. Among this a few grass seeds had found enough soil to enable them to send forth a rank growth which was now appearing. The mass or accumulation was about 10 inches deep and covered nearly the entire surface of the ledge, heaped up immediately under the new nest, forming an irregularly truncated cone of matter on which the nest was placed. In front of it huge icicles stood and joined with the slightly projecting roof above the ledge. Some of these ice columns were 2 or 3 inches thick and 4 inches wide. They formed an icy palisade around the edge of the nest and permitted approach to the interior only by a narrow space, or doorway, next to the main wall of rock. I was compelled to detach the ice before I could reach the four eggs which I saw within the nest. The nest was composed of a few twigs and branches of larch and spruce, irregularly disposed on only the outer side of the rim of the nest to prevent the eggs from rolling out, forming only a semicircular protection, while the rear portion was a part of the bare rock of the ledge. Below the twigs were the remains of former nests. Some of the sticks were so rotten that they would not support their weight when held by one end. The eggs were placed nearly touching each other.

Major Bendire (1892) writes:

Mr. R. MacFarlane, chief factor of the Hudson Bay Company, states that this Falcon is common in the wooded country on both sides of the Anderson River, and from the fact that over twenty nests were secured by him this must certainly be the case. All of these nests, with but two exceptions, were placed close to or near the tops of the tallest trees in the neighborhood, generally in pines. One nest was built on a ledge of rocks and the other against the side of a deep ravine. The nests were composed of sticks and small branches and lined with mosses, hay, deer hair, feathers, etc. They were similar in composition but smaller in size than those of the Bald Eagle, and while the number of eggs was either three or four, their contents were frequently found in different stages of development.

Both parents manifested much anger and excitement when interfered with, or even distantly approached. They made a great noise, and indeed more than once their folly in coming so near and screaming so loudly over our heads attracted attention to some that would otherwise have escaped notice. The earliest date of finding a nest was May 10, 1863, at Anderson River Fort, The eggs, three in number, were quite fresh. In another, taken five days later, the eggs contained partially formed embryos. In a few cases young birds were found in the same nest with eggs, the contents of which were but little changed, and in another nest a perfectly fresh egg was found with several ready to hatch. In nearly every case the eggs seemed to be in different stages of development, and incubation seems to begin as soon as the first egg is laid.

Eggs: I cannot do better than to quote Bendire’s (1892) description of the eggs, which will apply equally well to all the gyrfalcons, as follows:

The eggs are three or four in number. The ground color, when distinctly visible, which is not often the case, is creamy White. This is usually bidden by a pale cinnamon rufous suffusion. In an occasional specimen it seems to be pinkish vinaceous. The eggs are closely spotted and blotched with small, irregular markings of dark reddish brown, brick-red, ochraceous rufous, and tawny. These markings: usually pretty evenly distributed over the entire egg: are generally small in size, and more or less confluent. Some specimens show scarcely any trace of markings, the egg being of nearly uniform color throughout. * * * In the general pattern of markings the eggs of the Gyrfalcon approach those of the Prairie Falcon (Falco mexicanus) much closer than those of the Duck Hawk (Falco peregrinus anatum), which as a rule are much darker. In shape they vary from ovate to rounded ovate. The shells of these eggs feel rough to the touch, are irregularly granulated, and without luster.

The measurements of 55 eggs average 59.4 by 45.3 millimeters; the eggs showing the four extremes measure 63 by 46.5, 61 by 48, 56 by 46.2, and 61 by 42 millimeters.

Young: Mr. Turner says in his notes: “The young birds are able to leave the nest by the middle of August, and in September of some years they are quite abundant, flying over the houses at Fort Chimo with but little fear. They generally evince but little disposition to show fierceness, and on only two occasions did they display more than ordinary courage. They will not seize with the beak when wounded, but will grasp firmly with the claws. They immediately lie on their backs when wounded.”

Plumages: So far as I know, there are no specimens of the small downy young of this gyrfalcon in any American collection. Witherby’s Handbook (1924) describes a very young specimen of rusticolus as follows: “Down white with a slight creamy tinge, rather short, covering bird well on upper parts, but thinly on sides of belly and bare patch at base of sides of neck.”

A small nestling of the Iceland bird, in the Museum of Comparative Zoology, is about half grown but still largely downy; the “clove brown” juvenal plumage is growing on the crown, scapulars, wings, tail, and sides of the breast; otherwise it is thickly covered with long, soft, woolly down, white to buffy white in color. I have not seen any young of the black gyrfalcon in fresh juvenal plumage. Except for generally darker colors, it is probably much like the European bird of that age, of which Witherby’s Handbook (1924) says in part: “Upper mantle usually uniform dark brown, rest of mantle and scapulars dark brown, feathers with brownish-white edgings and spots; back, rump and upper tail-coverts with rather larger spots and edgings, often forming bars on upper tail-coverts; chin white, streaked dark brown; rest of under-parts very widely streaked dark brown, feathers of flanks mostly dark brown with white edgings and spots.”

Evidently the light-colored spots and edgings wear away during the first fall and winter, for many immature birds in our series have uniformly dark brown upper parts. Some, or perhaps all, of these may be more than a year old and may have partially molted their juvenal plumage. This first, postjuvenal, molt is much prolonged, beginning in summer, when the young bird is a year old, and continuing into the following winter. Consequently there are many birds in collections that are in this transition stage. All the immature specimens of Obsoletus that I have seen are heavily streaked on the under parts with “clove brown” or brownish black, in many so heavily that the dark color predominates. Mr. Turner says that “birds of the year may be distinguished by the color of the cere, tarsus, toes, and eyelids being of a pale blue, while in the adults these portions are bright yellow at all seasons.” Young birds do not reach maturity in plumage until they are nearly, or quite, 18 months old.

In the normal adult plumage the crown, mantle, and wing coverts are quite uniformly dark brown, “olive-brown” to “clove brown”, sometimes interrupted by a few whitish streaks on the nape; the lower back, rump, and upper tail coverts are grayer, or slaty plumbeous, but not nearly so bluish gray as in the European birds; the upper breast is heavily streaked, the belly heavily spotted with round spots, and the flanks broadly barred with blackish brown or nearly black. In some birds the entire body plumage, above and below, is nearly uniform, dark, sooty brown, with little or no whitish anywhere; these are probably melanistic individuals, or they may represent a dark phase.

Ridgway (1880) has described the adult plumage in detail. Adults apparently have one complete annual molt between June and January, though some of the primaries may be molted in spring.

Food: The food of this gyrfalcon is much the same as that of the preceding race, with due allowance for the difference in habitat. Mr. Turner says: “Their food consists almost exclusively of ptarmigans, little else ever being found in their stomachs. They seize their prey while on the wing, depending doubtless on their sudden appearance among a flock of ptarmigans to put their prey to flight when it may be secured. Their food is devoured on the ground. I have never seen them carry it in their talons.”

During their winter wanderings they feed on whatever living prey they can find, such as rabbits, squirrels, rats, domestic poultry, grouse, and wild ducks and geese. A bird in my collection, shot at Tiverton, H. I., on December 26, 1896, was hovering over some wooden duck decoys, as if about to pounce upon one of them. Henry A. Purdie (1879) recorded the capture of a gyrfalcon in Piscataquis County, Maine, in December 1876, of which he says: “It had caught several hens, and having pursued one under a. barn through a small opening was itself caught in the arms of a man as it came out.” Arthur H. Norton (1907) records the capture of a specimen near Portland Maine, on December 11, 1906; he writes: “It swooped into the hen yard of Mrs. John Smith on Allen Avenue, killing a large, pugnacious rooster, which it speedily began to devour.”

Behavior: Mr. Turner’s notes state that “their manner of flight is by extremely rapid wing beats followed by sailing for a few rods. They pass through the air with great rapidity; no bird of prey in those regions flies more rapidly. They dart upon their prey at a dash, bringing up, just at the moment of seizing, in an almost perpendicular position, doubtless to stop their momentum. I do not think they attempt to fly over the bird they wish to seize, but secure it by flying against and seizing it during the moment of shock. They fall to the ground with the bird seized.”

Maj. Allan Brooks (1900) says: “The flight of this Falcon is as a rule rather slow compared with that of other large Falcons, but when in pursuit of a Duck it gets up a tremendous velocity and can turn and twist almost as quickly as a Goshawk. In ordinary flight the wing stroke is much shorter than a Peregrine’s, and the bird when going straight away appears to be hovering like a Kestrel.”

Sir John Richardson (Swainson and Richardson, 1831) had a pair of gyrfalcons attack him while he was climbing in the vicinity of their nest; he writes: “They flew in circles, uttering loud and harsh screams, and alternately stooping with such velocity, that their motion through the air produced a loud rushing noise; they struck their claws within an inch or two of my head. I endeavored, by keeping the barrel of my gun close to my cheek, and suddenly elevating its muzzle when they were in the act of striking, to ascertain whether they had the power of instantaneously changing the direction of their rapid course, and found that they invariably rose above the obstacle with the quickness of thought, showing equal acuteness of vision and power of motion.”

Voice: Turner says: “The only note ever heard from this hawk was a chattering scream of the syllables, ke a, ke a, ke a, repeated a number of times, more rapidly toward the fifth or sixth utterance, and finally so blended that the sound is a rattling scream. The sound is produced only when danger is sighted.”

Field marks: This bird can be recognized as a falcon by its shape and manner of flight, as explained under the preceding race, but as a gyrfalcon only by its size. It is much darker than candicane in all plumages, sometimes appearing almost wholly dark brown, or almost black in certain lights.

Winter: The winter range of the black gyrfalcon is much the same as that of the white gyrfalcon, though it ranges more widely and somewhat farther south into the United States. Many individuals, mainly adults, remain on or near their breeding grounds all winter. Dr. Nelson (1887) writes: “Along the Lower Yukon and Kuskoquim Rivers in winter it is numerous, and finds an abundance of Ptarmigan, upon which it preys. At this season it is frequently seen perching on a stout branch of a tree overhanging the river bank, and I have seen it on several occasions allow a train of dog-sledges to pass within 40 or 50 yards, only noticing their presence by slowly turning its head.”

ASIATIC GYRFALCON
FALCO RUSTICOLUS URALENSIS (Sewertzov and Menzbler)
HABITS

This subspecies was described from specimens from the Ural Mountains in eastern Russia. Its range extends through Siberia to Kaynchatka, to the Commander Islands, to St. Lawrence Island, St. George Island, and probably other islands in Bering Sea, and to northern Alaska. A female in my collection, in fresh juvenal plumage, was taken at Deering, Kotzebue Sound, Alaska, on August 1, 1914; it was probably hatched in that vicinity, as it was still accompanied by its parent. A breeding female, with bare incubation spaces, was taken at Muller Bay, Alaska, on May 24, 1903. That this race migrates, or wanders occasionally, down the Pacific coast of North America is illustrated by an adult specimen taken iii December 1896 near Spokane, Wash.

D. Bernard Bull, who has had about 3 years of experience with this gyrfalcon on the Bering Sea coast of Alaska, has sent me some interesting notes on it; he says of its haunts and distribution: “The Asiatic gyrfalcon, like some other falcons, seems to prefer country that is open and free from timber for bunting, and where ledges of a rocky cliff or a high dirt bank are available for a nesting site. Such conditions prevail at Goodnews Bay and adjacent territory on the Bering Sea coast of Alaska, where this bird breeds and is partly, if not wholly, resident. I am confident also that it may be found nesting on Nunivak Island, at Nelson Island, and in the hills 15 miles east of the village of Hooper Bay. At these three places, although I did not take specimens, conversations with Eskimo natives convince me that gyrfalcons nest there regularly. In conversation with the natives, there was no doubt between us as to the specific identity of the bird, for we used the native name ka-guich-tuk, which is applied to the Asiatic gyrfalcon by the natives at all places mentioned in these notes.”

Nesting: Until Mr. Bull’s notes were received, we had very little information on the nesting habits of this gyrfalcon. The bird in my collection, referred to above, was shot on a ledge on some rocky cliffs in Kotzebue Sound, where its nest was probably located.

The “white” gyrfalcons reported by Dr. Leonhard Stejneger (1885) as breeding in the Commander Islands were probably all uralensis, as birds from Bering Island, now in the United States National Museum, are referable to this race. He writes: “The White Gyrfalcon breeds on Bering Island, though in limited numbers only. A pair had their nest in a steep and inaccessible rock in the so-called ‘Nakovainaja,’ a couple of miles from the main village.”

Mr. Bull has succeeded in finding and collecting eight sets of eggs of this rare gyrfalcon in the region referred to above; five of these were collected in May, two in April, and one in June; the earliest was taken on April 22, 1934, and the latest on June 8, 1934, with large embryos; there were five sets of 4, two sets of 3, and one set of 2, with small embryos. He writes to me: “On May 13, 1932, my first set of eggs was taken from a ledge on a dirt bank overlooking a valley near Goodnews Bay. Other sets were collected in 1933 and 1934, when seven good sets were taken. At this time, a total of 14 nesting sites were known to me, but it was not practicable for one person to visit them all in a single season on account of the breaking up of the ice at this time. I believe that the beginning of nesting varies each year according to the weather. In 1934 we had a very early year, the break-up occurring on April 22.

“The nests were on ledges overlooking the bay, a river, or a valley. No addition was made to them except an occasional feather. If located on loose dirt ledges, a hollow was scraped. Frequently they were in nests formerly occupied by American rough-legged hawks. That the Asiatic gyrfalcon resents any intrusion upon its nesting domain there can be no doubt, and he who admires temperamental display can never forget the actions of a gyrfalcon disturbed at its nest.”

Eggs: According to the brief description of the eggs, given to me by Mr. Bull, these do not differ materially from those of other gyrfalcons. I have no measurements of them.

Plumages: As this race is none too well known, and as no description is available in American publications, so far as the writer knows, it seems worth while to describe the known plumages in some detail. In general appearance this race is somewhat lighter and less gray above than rusticohts, much lighter and somewhat grayer than obsoletus, but decidedly darker than candicans. The wing formula given by the describers, fourth primary longer than first, seems to be very variable and unreliable as a subapecific character.

The Deering bird, referred to above, is in fresh juvenal plumage. The crown and nape are buffy white, streaked with “clove brown”, and much whiter than the back; in obsoletus the crown is uniform in color with the back, or even darker; the rest of the upper parts is “clove brown”, edged on the mantle and lesser wing coverts, and spotted, notched, or partially barred on the greater coverts and scapulars with pinkish, or buffy, white; there are broken bars of the same on the tail; the under parts are white, tinged with buff, with broad, elongated spots or streaks of “clove brown”; the inner webs of the primaries are deeply notched or barred with “light pinkish cinnamon” to white. In older immature birds the edgings have worn away and the buffy tints have faded out to white. At this stage the young are much like young birds from Iceland.

In fully adult plumage the crown is white to “pale pinkish buff”, heavily streaked, especially posteriorly, with blackish brown; the mantle, scapulars, and wing coverts are “olive-brown” to “clove brown”, more or less heavily, transversely barred with white, huffy white, or grayish white (not gray, as in European birds); the lower back, rump, and upper tail coverts are broadly banded with dark and light shades of “neutral gray”; the tail is broadly banded with “hair brown”, or “fuscous”, and gray mixed with white; the under parts are white, the throat and fore-breast pure white, except for a few narrow to almost invisible dusky shaft-streaks; the belly is spotted and the flanks are barred with sepia or blackish brown; the under tail coverts are barred with the same. Except for whiter heads and more white, less gray, in the barring on the mantles, these birds now look very much like adults from Europe.

Food: According to Mr. Bull, the food of the Asiatic gyrfalcon, in the Goodnews Bay region, includes the local subspecies of both the willow and the rock ptarmigan, as well as lemmings, snowshoe rabbits, minks, and weasels.

Behavior: J. A. Munro (1936) gives the following account of the behavior of one of these falcons that he observed in British Columbia, on December 19, 1935:

I was motoring past a small brush-fringed creek in otherwise open country when someone shot at, and missed, a female mallard which then flew over the open range toward Okanagan Lake. A large falcon suddenly appeared and flying after the duck on the same level gained upon it rapidly, whereupon the duck swerved from its former straight course and the falcon shot past it. The duck then spiraled down to a small ice-covered pond where it alighted. The falcon flew swiftly toward the standing bird and in the next five minutes or so swooped at it again and again, each time clearing the duck by a foot or more. After this it alighted on the ice about eight feet from the duck and remained there motionless for a few minutes. The mallard quacked continuously but did not move from its position. The falcon then rose and again began swooping at the duck. By this time my companion and I were walking toward the pond, one on either side and several hundred yards apart. When distant from the pond about 75 yards the mallard rose and flew toward Okanagan Lake and the falcon, passing close to my companion, was shot.

In the crop of the gyrfalcon were approximately two ounces of flesh from the breast of a male mallard, identified by the presence of the characteristic chestnut-colored breast feathers.

It is likely that the gyrfalcon was attempting to induce the mallard to fly, as the larger falcons seem to prefer to strike down their victims in the air, rather than pounce upon them on the ground; but, as these birds usually do not eat oftener than once a day, and as it already had considerable food in its crop, it may have been merely playing with the duck.