Northern Harrier | Life Histories of North American Birds | A.C. Bent
Feather Pic Arthur Cleveland Bent

Life Histories of Familiar North American Birds
A chapter from the electronic book: Life Histories of Familiar North American Birds

All Rights Reserved © This electronic book may not be copied, reproduced, or posted elsewhere, by any means, in whole or in part, without the written consent of the designer, editor, compiler, and copyright owner.
Northern Harrier
Circus cyaneus [Marsh Hawk]

[Published in 1937: Smithsonian Institution United States National Museum Bulletin 167 (Part 1): 78-95]

The above name [Marsh Hawk] recalls to mind those delightful days, now long past, when we sat for hours in a flimsy blind on the Cape Cod marshes, listening for the startling whistle of the yellowlegs or the mellow notes of the plover. The day is one of those lovely Indian summer days; only a gentle breeze is stirring, and the autumn haze softens the brilliant colors with which the waning summer has painted the marsh vegetation and the distant woods. As we sit there in the soft sunshine, dreamily drinking in the beauties of the scene, our eyes are alert to what is going on around us. Off on the distant mud flats are flocks of gray and white gulls, with scattered groups of shorebirds; over the extensive salt marshes black terns are winnowing the air, or plunging down into the grass for grasshoppers, and numerous swallows, now nearly ready to migrate, are skimming low over the meadows or the little pools; on a nearby sand flat some turnstones are digging holes in the sand; occasionally a great blue heron or a bittern flaps lazily over the marsh. There is always something moving; and, whether the yellowlegs and plover come to our decoys or not, we are sure to see, sooner or later, a dark speck in the distance that soon develops into a large, long-tailed, long-winged bird. On it comes with an easy gliding flight, its long wings slanting upward; as it turns we see its brownish breast and then its white rump, a young marsh hawk. A lazy, loafing, desultory flight it seems, but really it is full of purpose, as it quarters low over the ground in a systematic search for its prey. Often during the day it circles near us, but not too near, for all hawks have learned to avoid gunners. A peaceful day on the marshes would hardly be complete without an occasional glimpse of this industrious harrier, to add its touch of life to the picture.

But the marsh hawk's haunts are not limited to marshes. It is very common on the prairies and plains of the Middle West, though it shows a preference for the vicinity of sloughs and wet meadows. M. P. Skinner tells me that in Yellowstone National Park he sees "more of these hawks hunting over the rolling upland prairies than anywhere else." Here they "choose both the grassy meadows and the sage-and brush-covered hills to hunt over." He has even seen them "hunting across the open lands high up on the mountains," between 5,300 and 10,300 feet. Anywhere in open country, where prey may be found, the marsh hawk is likely to be seen.

Spring.--The marsh hawk is a migratory species. Most individuals spend the winter in the Southern States or in the milder sections of the country. But, even as far north as Manitoba, C. L. Broley tells me he has seen the species every month but January. There the light-colored males are the first to arrive, around the middle of March, and the brown females come about three weeks later. The season is about the same in southern New England, where some birds remain all winter near the coast.

Courtship.--Many accounts of the spectacular nuptial flight have appeared in print, but I prefer to use the following description of it, one of the best, in some notes sent to me by Mr. Broley:

This is a vigorous and pleasing series of nose dives, mostly done by the male, although the female frequently takes part in them. This takes place sometimes at an altitude of 500 feet, but the usual flight averages 60 feet up, swooping down to 10 feet from the ground. It might be illustrated by placing a number of capital U's together as UUUUUUUUUUUUUUUUUU, as the turn at the bottom is well rounded out, but at the apex the bird almost stalls, tipping downward again to continue the movement. Some observers claim it makes a somersault as it turns, but only on one occasion have I seen any indication of this. The wings are kept fully extended during the whole period, and they appear to be working easily all the time. I have seen a male make 71 of these dips in succession, fly on for a short distance, and commence anew. The average number of dips would be perhaps 25. The flight is frequently made while the female is flying along near the ground hunting for mice, below the male, or again he may swoop continually in one location while she is standing on the ground. The movement is extremely graceful and is a welcome sight each spring.

Other observers have described a similar performance, which seems to be characteristic of the species, but most of them have noted a complete somersault, or a sidewise turn, at the top of the rise. E. H. Forbush (1927) says: "As it bounds up and down in the air, it seems to move more like a rubber ball than a bird. . . . When two of these birds are mated or mating they keep together much of the time, either on the ground or in the air. When the female alights the male follows her and walks or flies around her. On the ground he bows to her and swells with amorous ardor. Sometimes the male flies alone across the marsh rising and falling alternately and with each fall turning a complete somersault, as if to show his larger mate what a clever and wonderful bird he really is. Again he 'carries on' in the same way while flying in her company."

Nesting.--In southeastern Massachusetts, at least in the region I hunt over, the marsh hawk is a rare breeder. My first nest was found in a sphagnum bog, overgrown with low huckleberries, pitcher plants, and scattered small larches, and surrounded with thickets of alder and swamp honeysuckle, a secluded spot. The nest was a flimsy structure of light, dry sticks and straws, loosely placed on the flattened tops of the low huckleberry bushes, only a few inches above the water and the thick growth of sphagnum moss and pitcher plants. It held five eggs on April 30, the last two having been laid during the past three days, indicating that the eggs may be laid on successive days.

Another and better nest was found in a somewhat different swamp; it was densely overgrown with alders, swamp azaleas, huckleberries, and other bushes, in some places higher than my head and difficult to penetrate, but in the center was a more open space, where the bushes were lower and more scattered, with a few brakes and flags growing up among them. Here the nest was placed on slightly elevated ground among some small bushes and brakes. It was a handsome and well-made nest of dry straws, weed stems, and sticks  and lined with finer straws, brake stems, and thistle tops; it measured about 23 by 20 inches in outside and 9 by 8 inches in inside diameter; the material in the center of the nest was about 2 inches deep. It held five spotted eggs on May 26.

But our local birds do not always nest in swamps. We have found them nesting on high and dry ground in what we call sprout lands, where woods have been cut off and where sprouts are growing on the stumps, but usually near a swamp or meadow. In such a place a similar nest to those described above is built on the dry ground and the larger stumps are used as perches or feeding stations. Other observers have described nesting sites at various eastern points.

Charles A. Urner (1925) made a careful study of three nests on the salt marshes of New Jersey, of which he says:

One nest was found in the center of a large clump of High-tide Bush (Iva oraria), and two were even more securely hidden in large beds of thick reeds (Phragmites communis). One was on dry, sandy ground, the other two on the wet marsh, occasionally flooded by tide.

Here I found an interesting difference indicating that the Harrier varies the height of its nest with the danger of floods in its chosen location. A nest found on dry ground, above all tide levels, constructed of weed stalks and grasses, nicely lined, was only an inch or two thick. A nest located on the marsh over a mile inland from the shore of Newark Bay, but more or less exposed to floods and unusual tides, was similarly constructed, but was about 5 or 6 inches thick. A third nest, found nearer the Bay shore and in a location frequently flooded, was remarkable for its greater size and bulk. It was built of weed stalks and finer material to a height of fifteen to eighteen inches, and it measured over three feet long and two feet wide. It was of uniform construction from the ground up with no indication of a "foreign" foundation.

In more western States the marsh hawk sometimes nests in bushy swamps or in brush-covered slopes, or even hillsides, but more commonly it selects more open grassy situations, the margins of sloughs, wet grassy hollows, or even extremely wet situations among reeds, flags, or tules. In Nelson County, N. Dak., we found five nests in one day, June 3, 1901. One was well made of sticks and straws and lined with soft grasses; it was built up 14 inches above the water in a patch of dead flags on the edge of a slough; it contained two young hawks, three normal eggs, one runt egg, and a dead spermophile. Another still finer nest, made of sticks, reeds, and coarse weeds, was built up 18 inches above the water in a wet meadow and measured 30 inches across the top. Other nests were similarly located.

Dr. John W. Sugden writes to me that in Salt Lake County, Utah, on July 18, 1928, he found a nest, containing five half-incubated eggs, "near the center of a 30-acre wheat field on a dry farm, at least 4 miles from the nearest water. The nest was a shallow depression in the ground lined with a few sticks and straws." Bendire (1892) mentions a nest found by George G. Cantwell on a haycock.

Both birds assist in building the nest, the male bringing some of the material and dropping it for his mate to arrange, but most of the gathering and arranging of material is done by the female. E. L. Sumner, Jr., watched a female building her nest and has sent me his notes on it. He saw her make seven trips to the nest within 10 minutes. He says:

In carrying the sticks, if they are small, she nearly always uses her bill alone; if they are large she uses her feet; in one case of a particularly large branching stalk she carried it in beak plus both claws; in another case she transferred a piece from her beak to her claws while sailing toward the nest. Once she carried a particularly large weed in her feet, but all the other times she used her bill instead. Once she picked up a piece, started to fly with it, but stopped and picked up another piece in addition, but in flying away with them, dropped the first one and then the other so that she had to continue on across the rush patch to the other side and pick up another load. Once I saw her tug violently at a weed that was still rooted, but it did not give way, and so she walked a few steps farther on and picked up a loose piece instead.

W. H. Laine (1928) reports finding a marsh hawk incubating on a nest of 12 prairie chicken eggs; the experiment was not a success, as only one chick hatched and it promptly ran away. Perhaps the hawk's nest had been destroyed and she adopted the nearest available nest.

Eggs.--Perhaps the commonest number of eggs is five, but four or six are frequently found and occasionally as many as seven or eight, or even nine, are seen in a marsh hawk's nest. In shape they are ovate, short-ovate, or nearly oval. The shell is smooth, with little or no gloss. The color is dull white or very pale bluish white. They are generally unmarked, but about 10 percent of the sets show, more or less, scattered spots of very pale browns, "cinnamon-buff" or paler, dull buff.

The measurements of 84 eggs average 46.6 by 36.4 millimeters; the eggs showing the four extremes measure 53 by 38, 48 by 39.5, 41.4 by 35.6, and 43 by 34 millimeters.

Young.--The period of incubation has been variously estimated as 21 to 31 days; the latter figure was definitely noted by Aretas A. Saunders (1913). It is difficult to determine, as it often begins when the first egg is laid; an egg is usually laid each day, but often a day or two may intervene between layings. Both sexes share the duties of incubation and care of the young, and they are very devoted parents. Mrs. Irene G. Wheelock (1904) writes:

In eighteen to twenty days the young Hawks break their hard shells, one each day, and cuddle down among the feathers and straw of the crude nest. From the day the first little ball of down appears, one or the other of the adults may be seen constantly on the wing over that meadow. The same tactics are pursued as before, for the food is dropped to the parent on the nest, who, after the first few days, holds it fast in her beak while the nestlings tear off bits from it for themselves. In this way the muscles of  the bill and neck are developed. Later on the food is simply dropped to them, both parents being off on the hunt, and the little fellows grasp it in their sharp claws and tear from it with a right good-will.

Aretas A. Saunders (1913) noted that three eggs in a set of five hatched between the evening of June 30 and the morning of July 1. The fourth bird hatched before the morning of July 2, the fifth on the afternoon of July 4, and the sixth on July 7. He noted that they were born with their eyes closed, but that they opened within a few hours. Following is his account of their development:

For the first six or seven days the young showed no change in appearance except that they grew larger and became somewhat more active. On July 8, just after the youngest bird had hatched, I noted that the oldest birds were about three times the size of the youngest. About July 10 the two youngest birds disappeared, probably having died. I believed that this was because they were so much smaller and weaker than the four older birds that they were unable to get their proper share of food.

Sheathed feathers began to appear in the oldest birds at the tips of the wings on July 8, when they were seven days old. On July 14, when twelve and thirteen days old, the birds began showing fear and crawled back into the cinquefoil bushes when I approached. When I attempted to handle them, they sat up and threatened me with their beaks, and called in a high, squeaky, baby voice. On July 17 the feathers at the tips of the wings began to break the sheaths, and sheathed feathers were appearing thickly on back, shoulders, breast and tail. At this time the feet and cere were beginning to turn from a light pinkish color to yellow. On July 22 the feathers were breaking the sheaths in many places, those at the tips of the wings being broken for about two inches of their length. The feet and cere were now bright yellow. The birds stood with outstretched wings and open beak, turning to face me no matter to which side of the nest I went. They were in about the same condition on July 24, so that I found it almost impossible to handle them. When I attempted to photograph them they crawled off into the bushes so that I could only get two at a time in the picture.

During the week following this the birds changed rapidly. Feathers unsheathed all over them, and much of the white down came off. On August 4, when the birds were thirty-three and thirty-four days old, I approached the nest and found three of them able to fly a little. One rose at my approach and flapped away for about 150 feet before it sank in the grass.

Mr. Urner (1925) found that the time from hatching to flight was about 30 to 35 days. He refers to them as "sturdy, fearless, wide awake, active, noisy and hungry youngsters. . . . The readiness with which the young imitate their parents is worthy of note. On July 7, I visited a brood which had left the nest and learned to fly, though still in the vicinity of the nesting site. They flew in all directions as I approached, uttering an immature peeping call. The adult male turned immediately to attack and I was surprised to see two of the young, probably males, follow suit, flying in very close and making a more or less unsuccessful effort to imitate the long rolling call."

As to the food of the young he says:

As far as I can judge from remains picked up in the general vicinity of the nests, mice and small birds, supplemented with insects, constitute the principal fare during early life. But as the birds grow, rats assume a more important role, and in or near two different nests I found remains, picked clean, of practically full-grown American Bitterns (Botaurus lentiginosus). Now the young American Bittern is no mean antagonist, and the fact that such large birds are actually killed and carried to the nest indicates the calibre of the Harrier as a hunter. . . . During the fourth week of the young Harrier's life pellets of fur and feathers, containing some bone, begin to appear about the nest. These pellets are often as large, as compact and as well formed, as those of the Short-eared Owls, constituting an interesting similarity between the two species. It is probable that the failure to find pellets about the nests earlier in the young brood's growth is due to the thorough removal of waste by the adults, rather than any change in feeding habits.

The main reason why pellets are not found about the nest during the early life of the young is that the old bird feeds the young, at that age, with small pieces of pure flesh. Dr. Frank N. Wilson (1927) saw, at close range, a marsh hawk feed a field mouse to her small young. "Holding it in her beak, she walked to the edge of the nest and, placing both feet upon it, tore off small pieces of the raw flesh and fed the young in turn. The coarser parts she ate herself."

After the young are able to fly they are often fed by their parents while on the wing. Dr. Charles W. Townsend (1905) writes: "Three weeks later near the same place, the female flew over my head, and whistled as she approached the nesting site. Upon this, four full grown young Hawks flew up to meet her and she dropped from her talons a mouse, which after falling about five feet was skillfully caught in the air by one of the youngsters. How it was done, whether in the bill or in the talons, I could not make out in the confusion. It certainly did not get by the birds, who at once retired to the ground, the successful one to eat its prize."

For a long time after the young are able to fly, the family group hangs together, hunting over the familiar grounds near their former home, the young learning from their parents and practicing the serious business of earning a living.

When the time comes for migrating, young birds are apt to wander widely in different directions. Young birds banded as nestlings by William I. Lyon, at Waukegan, Ill., were recovered that season, one at 50 and one at 300 miles northwest, and another at 500 miles southwest.

Plumages.--When first hatched the chick is covered with short down, very scanty on the under parts; it is pure white with only a short tinge of buffy on the upper parts. As the chick grows, the down increases in length and becomes darker, "pinkish buff," on the upper parts; the lores and a space around the eyes are naked. The development of the juvenal plumage is described by Mr. Saunders (1913) above. In fresh juvenal plumage, in August, the upper parts are "mummy brown," many feathers narrowly tipped, or broadly margined, or deeply notched, with "tawny" or "cinnamon"; the white upper tail coverts are tinged with "cinnamon"; the tail has four dark "mummy brown" bands, the four intervening bands being dark gray on the central pair of feathers and much mixed with "tawny," "cinnamon," gray, and white on the other feathers; the primaries are brownish black above, glaucous on the outer webs; the entire under parts are rich yellowish brown, "amber brown" to "ochraceous-tawny," broadly streaked on the chest and narrowly on the flanks with "bister," but otherwise immaculate. The sexes are alike in plumage, but there is a marked difference in size.

The juvenal plumage is worn for about a year but becomes much faded by spring; young males fade out to almost white below. Molting sometimes begins in April but usually not until summer, when a complete molt takes place from July to October or later. This produces a second winter plumage in which the sexes are different. Young males are quite dark above, "bister" to "mummy brown"' the under parts are largely white, with considerable drab and buffy mottling, especially on the chest, which is heavily clouded with drab; the wings and tail are much like those of the adult. Young females show similar progress toward maturing, but they still show many rufous edgings above; they can be distinguished from first-year females by their spotted breasts. At the next complete molt, the following summer, the young become practically adult in plumage, though probably males continue to grow whiter as they grow older. Adults have their complete annual molt during July, August, and September.

Food.--The marsh hawk is regarded by many as a highly beneficial species, mainly because of the large numbers of mice, rats, and other injurious small mammals that it destroys. It certainly is a great mouser; it lives largely on frogs and small snakes and devours many injurious insects, but the records show that many small birds and some larger ones are killed by it. Dr. A. K. Fisher (1893) gives the following summary of its food:

Of 124 stomachs examined, 7 contained poultry or game birds; 34, other birds; 57, mice; 22, other mammals; 7, reptiles; 2, frogs, 14, insects; 1 indeterminate matter, and 8 were empty.

Although this hawk occasionally carries off poultry and game birds, its economic value as a destroyer of mammal pests is so great that its slight irregularities should be pardoned. Unfortunately, however, the farmer and sportsman shoot it down at sight, regardless or ignorant of the fact that it preserves an immense quantity of grain, thousands of fruit trees, and innumerable nests of game birds by destroying the vermin which eat the grain, girdle the trees, and devour the eggs and young of the birds.

Maj. Allan Brooks (1928) condemns the marsh hawk, as "the most destructive hawk in all America to our marsh loving waterfowl for at least three months in the year." He accuses it of killing large numbers of young ducks and says that it does not kill its victim outright "but slowly wears the wretched captive out and literally eats it alive commencing at the breast muscles." He cites another case where a family of marsh hawks killed over two dozen old and young blue and ruffed grouse during one nesting season. These cases are probably exceptional, or extremely local in effect, for most of the evidence is in favor of the marsh hawk. Herbert L. Stoddard (1931) found remains of cotton rats, which destroy the eggs of quail, in 925 out of 1,100 pellets of this hawk. Several observers have mentioned the great service that marsh hawks perform in the southern rice fields by driving away bobolinks and blackbirds more effectively than hired men with guns, thus saving considerable expense.

Meadow mice seem to constitute the bulk of the food, according to nearly all observers. Judge John N. Clark wrote to Major Bendire (1892): "One I examined contained not less than eleven, another nine, and nothing else." Among other mammals taken are young rabbits, young skunks, pocket gophers, rats, spermophiles, squirrels, shrews, and moles. The long list of birds includes bittern, green heron, teal and other ducks, coot, rails, grouse, quail, partridges, pheasants, plovers, sandpipers, woodcock, snipe, sparrow hawk, screech owl, flicker, doves, starling, meadowlark, blackbirds, grackles, numerous sparrows, cardinal, towhees, warblers, wrens, mockingbird, catbird, thrashers, robin, bluebird, and thrushes. Frogs form a large item; and small snakes and lizards are eaten. It also feeds on large numbers of grasshoppers, locusts, crickets, and other insects. Ivan R. Tomkins tells me that in the saltwater marshes of South Carolina and Georgia "its winter food is mostly marsh rabbits (Sylvilagus palustris)." At times it is quite destructive to poultry and game. E. S. Cameron (1907) writes: "This bird is the common 'Henhawk' of eastern Montana and is the most pertinacious of any in attacks on the poultry yard. Young marsh hawks weighing about ten ounces will endeavor to disable a chicken weighing a pound, by pecking it on the head and striking on the back at the same time with the feet, their strong wings enabling them to keep directly above it no matter where the prey may run. Birds of the year, through inexperience, are the most daring, and my wife has taken a screaming pullet from the claws of one of them which found the prize too heavy to lift."

Henry K. Coale (1925) reported that a marsh hawk killed 7 of a flock of 14 Hungarian partridges within two weeks, before it was caught in a trap. "It would tear the back open and rip the flesh and skin off in strips."

The well-known habit of quartering the ground over fields or marshes, barely high enough to clear the tallest vegetation, is the common method employed to hunt its principal prey, small mammals and small birds. Its keen eyes are quick to detect its quarry, and its flight is under such perfect control that it can stop suddenly and drop quickly down upon the victim. Usually it is devoured right there on the ground, but often it is carried to some convenient stump or post, or carried away to feed its mate or young. A mouse or small bird may be almost wholly eaten, but a larger animal or bird will be skinned or plucked and the flesh torn off. When the victim is too large to be eaten at one meal, the hawk may return later to finish the feast. Dead game or even carrion is often welcome. A. G. Lawrence writes to me: "E. Robinson informs me that he has seen marsh hawks hovering in front of a prairie fire, picking up the mice as they fled before the flames. I have seen a marsh hawk hover for more than 5 minutes over a bush in which a small bird had taken refuge, darting rapidly from side to side when the bird ventured to fly out, but mainly hovering over the bush about 10 feet up. Eventually it swept down beyond the bush and secured its victim as it tried to escape."

Several observers have noted the interesting way in which the male feeds his mate. C. L. Broley has sent me the following note on it: "The male flies with the mouse near where the female may be nesting and calls to her; upon which she takes to the air; and, flying 12 to 20 feet over his mate, the male drops the mouse. The female either turns partly on her back and catches the mouse with her claws  or, as on one occasion, just swings her feet out to the side and catches the mouse neatly. I have seen the male carry a mouse 15 minutes awaiting the return of his mate to present it to her. Another time the male became tired of waiting for her and ate half the mouse but kept the other half till she returned."

Eugene S. Rolfe (1897) noted the following interesting attempt to secure a meal: "Many times I have watched the Marsh Hawk sailing low and keenly scanning the ground on the open prairie, and suddenly pouncing down and quickly ascending again with an empty mouse nest in its talons, and one one occasion I followed behind for fully 2 miles and in that distance it picked up and dropped seven of these empty nets. On examination they proved to be simply wads of fine dried grasses, and it was easy to see that if these had all chanced to be occupied by families of young mice, the foray of that particular Hawk would have been most fruitful in the destruction of these small pests."

E. L. Sumner, Jr. (1931) witnessed a playful reaction of a marsh hawk with a horned lark that it had captured:

All at once the hawk dropped the lark, whereupon the latter, still alive flew weakly to the ground about seven feet away, its captor with outstretched talons hovering meanwhile about two and one-half feet above it but not pouncing upon it. When the lark reached the ground, the hawk lit beside it, then gave a little jump into the air and landed with spread talons upon its prey. It seemed not to bite the lark, but after examining it with many twistings and turnings of the head rose about three feet into the air with it, and then dropped it again, the lark still fluttering, and pounced upon it just as before. This the marsh hawk did seven or eight times, and I marveled at the clumsiness of the bird until I realized what was going on--it was playing.

At length the lark fluttered into a tangle of shrubby weeds, which circumstance seemed to furnish even more interest for the hawk. It would prance about in the weeds, taking great high steps, and now and again bend down to peer intently in at the lark. I do not think the hawk at any time really lost its prey. This continued for about ten minutes from the time when I had started to watch, after which the bird settled in a little depression with its victim and was then out of sight.

Behavior.--Much of this subject has already been covered under other headings. The characteristic low flight, as it quarters over the wide open spaces in search of food, is light, buoyant, graceful, and easy, as well as long protracted and apparently tireless. William Brewster (1925) has described it perfectly, as follows: "Flying ever in the buoyant, unhurried manner so characteristic of their race, now renewing waning impetus by a few deliberate wing strokes, next gliding for several rods on wings set with the tips held well upwards, much as those of a gliding Turkey Vulture are held, tilting their bodies more or less perceptibly from side to side and rarely pursuing a perfectly straight course for more than a few yards at a time, they may skirt the shore for miles, following all its windings closely, and keeping just outside the outer ranks of living trees, but taking no especial pains to thus avoid outstanding dead ones."

While migrating it flies at a higher elevation with steadier wing beats. Its nuptial flight is spectacular and shows its ability as an aviator and a stunt flier, for which the long wings and tail, combined with a light body, are well adapted. Its lofty evolutions are not so well known, but it compares favorably with other hawks in its soaring ability. Mrs. Bailey (1915) says: "When flying high enough to be exposed to the strong prairie wind, her maneuvers, and those of the male when he joined her, were fascinating and beautiful to watch. After flapping low over the ground, they would set their wings and, perfected monoplanes, rise with the wind, tilting and turning, changing their angles with enviable skill to meet the vagaries of the air currents. They would sail with set wings, buffeted by the wind, and then, as if their sailing muscles were tired, turn tail in midair and sweep back with a beautiful downward curve."

Marsh hawks occasionally perch on trees or bushes, but only rarely; they normally stand on the ground or perch on stumps, fence posts, or telegraph poles. They even roost on the ground at night. They have favorite perching, feeding, and roosting stations, which are well marked with pellets, excrement, and feathers. Mr. Stoddard (1931) says: "This species has the un-hawklike habit of roosting on the ground, frequenting the same spot night after night. If numerous, these hawks form a loose roosting group numbering from two or three, to as many as thirty. A large field grown up to heavy broom sedge and preferably upon a hilltop is chosen as a roosting site. Each bird has a beaten down spot in the sedge, well 'limed' with the droppings."

J. D. Smith shot a male marsh hawk just after daybreak of a very frosty morning; its back and tail feathers were covered with frost.

I have no brief for the marsh hawk as a gentle, harmless bird; on the other hand, I consider it a decidedly intolerant, aggressive, and pugnacious defender of its home territory, as everyone knows who has ever attempted to invade its precincts. Especially when there are young in the nest, or even after the young are on the wing, one or both parents are sure to attack the intruder. Some say that the male is more aggressive, but I have seen very little difference. I have had them dash at my head repeatedly, and keep it up as long as I was anywhere near the nest; flying off for a short distance, the hawk would turn and come like a flash straight for my face, as if it would surely strike me; but it always just missed me by a few inches. A. D. DuBois writes me: "While I stood near a nest, trying to arrange a tripod and camera, the parent marsh hawk repeatedly struck me on the head. In one of these onslaughts she lifted my hat and dropped it on the ground. Her claws penetrated the hat sufficiently to scratch the scalp."

Mr. Saunders (1913) had a marsh hawk attack him frequently when he was a long way from the nest and often not headed in that direction, once when he was a mile away from it. Mrs. Bailey (1915) had similar experiences. Elon H. Eaton (1910) had the bellows of his camera, which he had concealed near the nest, torn to pieces by the attacking hawk. Paul L. Errington (1930) gives an interesting account of the territory disputes of three pairs that nested within 400 yards of each other; each pair had its definitely outlined territory, on which none of the others were allowed to trespass.

No less intolerant is their behavior toward other species. They have been seen repeatedly attacking red-tailed and red-shouldered hawks that were peacefully soaring over their domains. They always drive away crows and have been known to attack and drive away eagles. They often drive away sparrow hawks, blackbirds, and other small birds without attempting to catch them. Walter B. Savary writes to me that he "saw a marsh hawk with a mouse in its claws trying to escape from three crows that were pursuing it in an endeavor to get the mouse. So close at last were the crows that the hawk let its prey drop; without checking its flight, the leading crow snatched up the mouse and continued on, to be at once followed by a caracara, which, in turn, forced the crow to drop its prize. This happened so near me that the hawk dared not to pick up the mouse, but perched on a nearby stub and waited."

Even the bold and dashing duck hawk is sometimes robbed of its prey, but sometimes the tables are turned. Forbush (1927) relates a story, told him by William G. Means, of a duck hawk that knocked a marsh hawk off a fallen duck it was eating. On the other hand, C. J. Maynard (1896) writes: "The Marsh Hawks are, as a rule, not very bold but I once knew an exception to this and, while in Florida, some years ago, repeatedly saw one of these birds rob a Peregrine Falcon of Ducks which it had captured. This appears almost incredible, but I was once quite near when the Marsh Hawk took possession of the booty of the Falcon that was sitting on the ground, and I distinctly saw the latter give up his prey, almost without a struggle, to the venturesome Hawk which coolly began to eat it, utterly disregarding the screams of the Falcon that was darting about a few yards above him."

I have often noticed, in a large colony of breeding terns, that as soon as a marsh hawk appears on the scene their otherwise ceaseless din suddenly stops, every voice is still; the silence is so striking that we look up to see the cause, as thousands of white wings are diving after him in an angry mob, and he is forced to beat an hasty retreat. I have no evidence that the hawk ever molests the terns. I have seen the same phenomenon in a densely populated colony of yellow-headed blackbirds in a western slough.

Lewis O. Shelley (1930) enjoyed an unusual experience in taming some young marsh hawks that he raised from the nest, of which he writes:

They flew anywhere they wished and were always called by a whistling note. They flew all about the village and to points a mile or more distant at least, without harm by humans befalling them. Their maneuvers were at once interesting and unbelievable at the same time to everybody, including myself. That they became perfectly tame and came to me when called, was a reaction considered remarkable in a wild raptorial bird. . . .

During the fall migration, vireos, warblers, sparrows--many species--would feed contentedly in the same tree, on the same limb, with one of the hawks. I never saw an attempt of the hawks to molest them. Our own and the neighboring hens became used to the hawks and did not become frightened when they alighted in the hen yards. . . .

At any time when I wanted them to exhibit to visitors or for other reasons, if within hearing distance they always came. If I merely whistled to answer their common "contented" call they took it for what it meant and remained where they were, often shifting their positions to be able to watch me. A sharp whistle served as "mess-call" and was responded to promptly--quite so. Perhaps the greatest thrill was in having them alight on my person, anywhere, at any time; to be able to handle them to my utmost content without fear of injury; to call them when I left work at the store and have them fly home with me for the evening meal. . . .

As to sight and hearing, their instincts were unsurpassed. Any noise, and a good many too slight to be detected by human ears, was noted instantly with whatever reaction suited the case at hand. To illustrate the eyesight: I once held an inch cube of meat in my finger tips over my head, uttering no sound. A hawk perched in a tree about one hundred and fifty yards distant immediately rushed to me, eyes upon the tid-bit, and without slacking speed perceptibly, grasped it with a downward lunge of one foot and wheeled back to its perch triumphant. If a piece of meat about an inch square was accidentally dropped in the tall herd's grass when flying to the woods, where I, searching keenly, could not find it, the bird poised in mid-air above the spot would see it instantly, alight and eat it. They did this on several occasions. I believe this well illustrates the power of the eyesight when a foraging Marsh Hawk sails over a meadow searching for field mice. Small chance a moving body has of escaping the keen eye!

Voice.--The several notes of the marsh hawk have been variously interpreted by different writers. Mr. Forbush (1927) has made a choice collection of these, which I quote with authorities:

Alarm call of male, "a shrill screaming 'cha-cha-cha-cha-cha-cha' " (Florence M. Bailey); female, "a prolonged shriek---'kee, kee, kee, kee, kee, kee, kee, kee' "; or " 'check-eck, check-eck, check-eck, check-eck, check-eck, check-eck' " (Bailey); "a series of syllables like 'kuh! kuh! kuh!' repeated very fast and quite a number of times without pause (H. O. Green); female when disturbed at nest, a flicker-like call sounding like 'pe'-ter pe'-ter pe'ter'; another call 'stee-whit-a-whit-a-whit,' also 'pee pee pee' repeated fifteen to twenty times and 'swit, wat, wat,' the notes sometimes run together like a whinny (C.W. Townsend); rather weak nasal whistle, also a sort of chuckle; at nest with eggs 'quip-quip-quip-quip-quip'; male at times has a complaining , scolding note like 'chu-chu-chu' or 'choo-choo-choo,' quite unlike the usual short, weak but sharp whistle of the bird--this when nesting area is invaded. The male's voice is deeper, fuller, and heavier than the female's higher-keyed note (J. A. Farley).

Field marks.--The adult male is the whitest of any of our common hawks, with black wing tips. In all plumages, the white rump is conspicuous. The everglade kite, Harris's hawk, and the rough-legged hawk all have similar white patches; the first two have comparatively restricted habitats in the South and have other field marks; the rough-legged hawk is a more heavily built bird and has the white mainly on the tail instead of on the rump (upper tail coverts). At any reasonable distance the marsh hawk can be recognized by its slender form, its long slim tail, and its long wings, held at an upward angle except when soaring. Its manner of flight described above, is distinctive.

Fall.--Late in August or early in September the fall migration begins in New England. Mr. Forbush (1927) says: "The principal migration here seems to move along the coastal plain. Many marsh hawks coming south through the region below Boston follow down the west side of Buzzards Bay and then turn westward across Narrangansett Bay and along the coasts of Rhode Island and Connecticut."

By the middle of November most of these hawks have left the northern parts of their range, though they linger on the way as long as they can find enough mice and small birds to hunt. Audubon (1840) writes: "I have observed it in our western prairies in autumn moving in flocks of twenty, thirty, or even as many as forty individuals, and appearing to be migrating, as they passed along at a height of fifty or sixty yards, without paying any attention to the objects below; but on all these occasions I could never find that they were bent on any general course more than another; as some days a flock would be proceeding southward, on the next to the northward or eastward."

Maurice Broun's (1935) records for 1934 at Kittatinny Ridge in Pennsylvania "extend from September 24 to November 24. The majority of the 105 individuals recorded passed through between October 10 and November 10. The greatest number seen on one day was 11 on October 18, and 11 on November 3. The females precede the males, apparently, as most of the 51 birds that occurred up to October 19 were of the former sex. Of 38 Marsh Hawks observed from November 1 to 12, 28 were males."

Winter.--A few individuals remain, during mild winters, on the coastal mashes of southern New England, or in other suitable localities throughout the Northern States; but the great majority follow the migrations of the small birds southward, and spend the winter in the Southern States, the land of plenty.

Northern Harrier* Circus cyaneus [Marsh Hawk]

*Original Source: Bent, Arthur Cleveland. 1937. Smithsonian Institution United States National Museum Bulletin 167 (Part 1): 78-95. United States Government Printing Office