[Published in 1938: Smithsonian Institution United States National Museum Bulletin 170: 295-322]
As an introduction to this grand species, I cannot do better than to repeat the following well-chosen words of Ernest T. Seton (1890), which so well express my own sentiments: "My ample opportunities of fully observing these interesting birds in captivity as well as in a state of freedom, and indeed all that I have seen of them--their magnificent bearing; their objection to carrion, and strictly carnivorous tastes--would make me rank these winged tigers among the most pronounced and savage of the birds of prey."
The great horned owl, with its various subspecies, is widely distributed throughout the timbered regions of North, Central, and South America, from the Arctic regions in the North to the Straits of Magellan in the South. ***
Our eastern race particularly is essentially a bird of the heavily forested regions, where it finds seclusion and ample food supply in the dense, dark woods. Where there are extensive forests, well stocked with small game, it is a common bird, but it is also found in lesser numbers where scattered woodlands still remain and where it can prey on poultry yards and game preserves. In my local territory, in southeastern Massachusetts, the distribution of the great horned owl coincides with that of the red-tailed hawk; I have always considered these two as complementary species, one hunting by night and one by day in the same region; the same relation seems to exist between the barred owl and the red-shouldered hawk. We usually find the great horned owl nesting in old nests of the red-tailed hawk, but I have never found these two species nesting in the same tract of timber simultaneously, as the barred owl and the red-shouldered hawk often do. I believe that the great horned owl will not tolerate the nesting of any other raptorial bird anywhere near its own nest.
Courtship.--During the January thaw, or on the first soft, warm evenings of February, we used to listen for the love songs of these owls, for they start their preparations for nesting very early in the season, and they are very noisy at this time; their prolonged hootings at this season have often helped to locate a nesting pair; but I have never been fortunate enough to see the courtship performance. Dr. Lynds Jones wrote to Major Bendire (1892): "I once had the good fortune to steal unnoticed upon a pair of these birds in their love making. The ceremony had evidently been in progress some time. When discovered the male was carefully approaching the female, which stood on a branch, and she half turned away like a timid girl. He then fondly stroked his mate with his bill, bowed solemnly, touched or rubbed her bill with his, bowed again, sidled into a new position from time to time, and continued his caresses. All these attentions were apparently bashfully received by the female. Soon thereafter the pair flew slowly away side by side."
Floyd Bralliar (1922) gives the following account of it:
So he began bowing his head, ruffling his feathers, raising his wings and spreading his wings in a curious manner. . . . Aside from watching his antics, she took no notice of his presence. Growing more earnest, he began hopping from branch to branch, continuing his maneuvers and snapping his bill fiercely as if to show that even tho he was not so large as she, what he lacked in size he made up in bravery.
Finally, he attempted to approach and caress her but she ruffled her feathers and rebuked him sharply. He took flight, sailing up and down, around and around, evidently doing all the stunts of his race, now and again punctuating his efforts by snapping his bill. After a few moments he alighted again and began his bowing and dancing all over again.
A rabbit came running down the bank and its white flag caught his eye. Rising in noiseless flight, he sailed downward without the flap of a wing, caught his prey from the ground, glided back into the tree, and presented his offering to his lady love. Apparently, she was convinced of his sincerity. Together they devoured the rabbit, and when he again began his love dance she joined in with as much enthusiasm as he.
Nesting.--The great horned owl has never been a common bird in southeastern Massachusetts. I hunted for 20 years before I found a nest containing eggs. I find only 13 local nests recorded in my notes; four of these were found during one season, 1907; in other years I have never found more than one each year; but during 1933 my companions, Alfred C. Weston and W. George F. Harris, found four nests of this owl in this general region.
All my nests but two were in old nests of the red-tailed hawk; one was in an old squirrel's nest, and one in an old nest of the red-shouldered hawk. All were in the heaviest timber available and as far as possible from human habitations. Nine of the nests were in white pines (Pinus strobus), three were in pitch pines (Pinus rigida) in a region where no white pines were available, and one was in a large beech tree. The nest in the beech was only 31 feet from the ground, those in the pitch pines were from 38 to 42 feet up, and the white pine nests varied from 40 to 70 feet above ground.
Only twice have I known a pair of the owls to lay a second set after being robbed; these were laid after an interval of three or four weeks, and in both cases the same nest was used for both sets. The great horned owl, according to my experience, does not show the persistent devotion to its nesting area that is shown by the barred owl and, particularly, by the red-shouldered hawk; whereas these other two have been known to nest in the same patch of woods for many years in succession, I have never known Bubo to nest in the same tract for more than four years, and this has happened only twice in my experience. My theory is that these owls are such voracious feeders that they exhaust the supply of small game, often within one or two seasons, and have to move to new hunting grounds.
The nest from which I took my first set of eggs, on March 4, 1907, was an old red-tailed hawk's nest, 57 feet from the ground in a tall white pine, located in a swampy hollow in a large tract of heavy timber, pines maples, oaks, and yellow birches. The nest was made of pine sticks and twigs, was full of dead pine needles, and was lined with short, broken twigs and a lot of buff-colored down from the owl's breast. It rested securely on four large branches, against the trunk and very near the top of the tree. It measured 31 by 22 inches in over-all diameter, the inner cavity was 12 inches in diameter and 2 inches deep, and the outside depth was 8 inches.
The smallest nest that I have seen was in an old squirrel's nest, 52 feet from the ground in the topmost crotch of a tall white pine; it measured only 18 by 16 inches in outside diameter but was deeply hollowed to a depth of 8 inches. The rubbish and dirt had been scraped out, down to the bare branches, and there was no lining except for a few downy feathers of the owl.
My most interesting nest was the one in a historic old beech, in a large tract of heavy, mixed timber, which had been the home of a pair of red-shouldered hawks or a pair of barred owls for many years. This nest was built by the hawks and occupied by them in 1907. On April 3, 1909, we were surprised to find that a pair of great horned owls had invaded this territory and taken possession of this nest; this was the first and only time that I have known this owl to usurp a nest of this hawk. The owls had, apparently, brought in some fresh sticks and added a few fresh sprigs of white pine, and the nest was well lined with the downy feathers of the owl; this fresh material may have been added by the hawks, which may have been driven away by the owls after they had started repairing the nest. But Bubo did not long remain in possession of this nesting site, for we robbed the nest, and the barred owls appropriated the nest in 1912. In 1913, 1915, and again in 1928, the red-shouldered hawks, probably the original owners of the nest, occupied their old home. Since then the nest has disappeared.
Our experience with this nest was not entirely unique, for other somewhat similar cases of several species using a nest successively have been recorded. John N. Clark (1887) found a pair of Cooper's hawks nesting in the lofty crotch of a large chestnut, near Saybrook, Conn., in 1884; the following year this nest was occupied by a great horned owl, from which he secured a set of two eggs; in 1886 he was surprised to find that a pair of red-tailed hawks had appropriated the nest; and in 1887 he collected a set of barred owl eggs from this same old nest. It was indeed a popular nest to attract four species in four succeeding years.
The great horned owl is our earliest breeder, often laying its eggs in February, and sometimes in January, as far north as New England and New York, a month or six weeks earlier than our largest hawks. It seems remarkable that its eggs should be laid before the snows of winter have gone and while they are likely to freeze if left unprotected; but the reason is obvious when the following facts are considered. The period of incubation is about 28 days, the young remain in the nest about six or seven weeks, and are unable to fly until they are 10 or 12 weeks old; this means that if the eggs are laid about the first of March, as they usually are in this latitude, it will be the middle or last of June before the young are able even partially to shift for themselves. During all this time, and probably for some weeks longer, they must be fed wholly or partially by their parents. They are exceedingly voracious feeders, as the following records will show, their food is difficult to obtain, especially where game is scarce, and it is much easier for their parents to supply their needs before the summer foliage becomes too dense.
Such early nesting requires constant brooding of the eggs during cold or stormy weather; sometimes the nest and even the incubating bird are covered with snow, but the devoted mother generally succeeds in keeping the eggs and the center of the nest dry and warm. Sometimes, however, the eggs are frozen and fail to hatch. C. A. Hawes (1881) tells of a case where the owl, finding that her two eggs were frozen, laid two more in the same nest. "Two of the eggs were in the middle of the nest, and sunk about two thirds their depth into the lining, and were much discolored from being in contact with the wet moss and cedar bark. When blowing them they showed about seven days incubation, but were badly addled. . . . The other two eggs were a trifle smaller, but quite free from any stains, and were quite fresh."
Baird, Brewer, and Ridgway (1905) say: "The mating of this bird appears to have little or no reference to the season. A pair has been known to select a site for their nest, and begin to construct a new one, or seize upon that of a Red-tailed Hawk, and repair it, in September or October, keeping in its vicinity through the winter, and making their presence known by their continued hooting."
Throughout the Middle West, where large tracts of heavy timber are scarce and where the food supply is adequate, the great horned owl nests in much more open situations than it does in New England. Prof. Charles R. Keyes (1911) gives us a full and interesting account of such a nest, found near his home in Mount Vernon, Iowa. A "beautiful deciduous forest" along the Cedar River had been reduced to scattered groves, and in one of the largest of these he had seen the owls. "Soon after, the great oaks and hard maples of the eastern two-thirds of the grove fell under the ax, leaving to the west only a twenty-five acre remnant and, in the cut-over area, only some old white elms and a few young maples and lindens. Among these latter the forest soil soon gave way to a thick carpet of blue grass and so what had been heavy forest was gradually transformed into a rather open and still very beautiful timber pasture." Of the nest he says:
It was not in the heavy timber at all but in one of the large elms of the pasture, and, moreover, hardly more than fifty yards removed from the above-mentioned public road where teams were constantly passing. Toward the south the view was wild, open, and picturesque enough; to the west, north and east, at distances varying from 200 to 500 yards, were the schoolhouse and farm houses. . . .
The nest was in a large shallow hollow, 28 x 32 inches in diameter at the bottom with an entrance 18 x 20 inches in diameter set at an angle of 45 degrees and facing towards the southeast. The hollow was only 8 inches deep on the exposed side, thus permitting fairly good illumination. Of still more importance the nest site was only 22 feet from the ground and a strategic branch some five feet above the nest afforded a point of attachment for a ladder combination from which pictures might be taken. . . . At the very moment when this nest was discovered a second pair of these birds were domiciled in a Redtail's nest placed in a tall white elm in heavy timber three and a half miles to the northwest and just ninety-two feet above the ground.
Thinking that the weather was too cold to keep the owl off her eggs long enough for photography, he pocketed the three eggs that the nest contained on February 17 and relied on her laying a second set; this she did, and on "March 23, three more eggs were found, just like the first and lying in exactly the same little hollow." From that time on a fine series of photographs were taken, and observations made on the life history of these owls.
Major Bendire (1892) says:
Mr. George E. Beyer, of New Orleans, Louisiana, also found a nest of this species, containing three young, in a hollow pine log on the ground. . . . Mr. Audubon also says that he has twice found the eggs of the Great Horned Owl in fissures of rocks. . . . Col. N. S. Goss, in his "Birds of Kansas," states that on the plains or treeless portions of the state it likewise nests in fissures of rocks. These birds are poor nest builders, and if they do construct one of their own, it is through necessity and not from choice. In the eastern states the majority use open nests, generally those of the Red-tailed and Red-shouldered Hawks, the Crows, and sometimes from those of the larger Herons, while farther west hollow trees, when procurable, are still, to a considerable extent, resorted to. . . .
Judge John N. Clark, of Saybrook, Connecticut, writes me that he found a pair of these birds nesting in a quadruple fork of a large chestnut tree some 25 feet from the ground, the eggs lying on the bare wood, without any loose material around them whatever, not even a single leaf. Mr. P. W. Smith, Jr., found another pair occupying an old soap box which had been originally put up for squirrels in a grove not over 100 yards from a house. The top of the box had blown off and it was nearly filled with dry leaves.
He quotes Dr. William L. Ralph as follows:
In the Indian River region of Florida, the Great Horned Owl usually lives in the pine wood districts, breeding altogether in these localities, and I have never known it to nest in other situations in any part of this state that I am familiar with. At and in the vicinity of Merritt's Island, where I visited for several winters, these birds were so common that eight of their nests were found in one season while looking for those of the Bald Eagle, but, like most Florida birds, they are gradually decreasing.
In this region these Owls always deposit their eggs in the nests of the Bald Eagle, and while I think that these are usually, if not always first deserted by the original owners, the natives say that the Owls drive the Eagles from and appropriate them for their own use. . . . These nests are originally constructed of large sticks and limbs, lined with dead grasses, palmetto leaves, flags, and weeds--usually with swamp grasses alone--and after being taken by the Owls are always further thickly lined with scales of pine bark, a material I have never found in any quantity in the nests occupied by the Eagles. The amount of this bark in each nest seems to be about the same, which would not likely be the case had it fallen into the nests by chance, which may occasionally happen to a limited extent. In addition to this bark there are always more or less feathers from the birds in this second lining. Many birds of prey line their nests with leaves of bark from resinous trees and they do this as a preventive remedy for parasites, with which they are always more or less troubled. . . .
These birds become very much attached to certain localities and seldom wander far from them, even in cases of extreme persecution. As a usual thing they will, should their nest be disturbed, take another in the immediate vicinity, and after a season or two return again to the first one; but in this locality I have known one of these Owls to lay a third set of eggs in the same nest from which the first two had been successively taken. In Florida this species usually commences breeding in December. I have taken eggs about one-third incubated December 17, and found nearly fresh ones January 5. These are the earliest and the latest dates of which I have any personal records, and have never found more than two eggs in a nest, and about 60 percent of the sets consisted of a single egg.
Donald J. Nicholson has sent me his notes on 14 nests found by him in Florida. Eleven of these were in old nests of the bald eagle, and three were in red-tailed hawks' nests. The earliest date on which he found eggs was December 7, but he found young as early as December 26, which indicated an earlier egg date. In one case, where the owl had preempted a brand new redtail's nest, he flushed the owl off the nest; the owl alighted in the top of a palmetto and was attacked by the hawk, which "dived like a bullet at the thief and gave it a stunning blow," and the "owl flew rapidly away."
Dr. Paul L. Errington (1932a) writes:
None of the twenty-nine 1930-1932 Wisconsin horned owl nests upon which personal data were procured showed evidence of having been built or remodeled to any degree by the strigine occupants. In practically every case the owls' nest-making instincts seemed satisfied by cleaning out the debris from the immediate bottom of the nesting place and by lining the same with variable quantities of breast feathers. Nest sites chosen were: red-tailed hawk nests, thirteen; crow nests, eight; hollow trees, three; unidentified stick nests, two; holes or crevices in rock faces, two; fox-squirrel nest, one. Nests taken over were usually in secluded locations, the prospective occupants requiring mainly privacy and convenience; in other respects the birds displayed very limited judgment in selecting nests, as four were of such flimsy construction that they disintegrated during the storms or from use, to dump eggs or owlets on the ground.
Herbert W. Brandt writes to me that in Texas they "show a great variation in nesting sites, generally utilizing old hawks' nests, but nests are also found in rocky caves, hollow trees, and, in the prairie region, even on the ground. We found one nest in the long grass near a windmill."
Ivan R. Tomkins tells me that he found two young owls of this species "in a shell hole on the east side of old Fort Pulaski." R. C. Hallman (1929) found a nest on the ground in Florida; "the nest, which could hardly be called one, was placed on the ground, and was composed of a few parts of dry palmetto fans, grass stems and small sticks." Horned owls have also been reported as nesting on the hay in barns and hay barracks, which stood in open spaces and were much frequented; the owners of such places did not disturb them, as they were so useful in destroying rats and mice.
From one to five eggs have been found in a set, but as a rule two or three are all that are laid, the smaller number more frequently. In some sections, however, sets of four are not unusual. Mr. J. W. Preston, of Baxter, Iowa, writes me that this number is found by him about once in three sets, and that in the early part of March, 1875, he found a set of five eggs too far advanced in incubation to disturb them, and which were all hatched later. . . .
I believe that where the Great Horned Owl nests in hollow trees the number of eggs laid by them is usually apt to be larger than where an open nest is used. The young are more secure in such a location and not so likely to fall or be crowded out. . . .
The eggs. . .are white in color, and show little or no gloss, though there are occasional exceptions; they are rounded oval in shape; the shell is thick and rather coarsely granulated, feeling rough to the touch.
Dr. Ralph told Bendire (1892) that 60 percent of the nests he found in Florida contained only one egg. Of the 14 nests recorded by Mr. Nicholson, two contained three eggs, three held only one egg or young, and the others were sets of two. All my Massachusetts nests contained two eggs or two young, never more or fewer. Apparently the large sets are laid in the Middle West, where perhaps the food supply is more abundant.
The measurements of 53 eggs average 56.1 by 47 millimeters; the eggs showing the four extremes measure 59.9 by 50.3 and 50.8 by 43.2 millimeters.
Young.--The following account of the development of young great horned owls is based partially on my own studies of two of the four broods of young that I found in 1907 and partially on the published and unpublished notes of Professor Keyes, E. L. Sumner, Jr., and Dr. Alfred O. Gross.
Two nearly fresh eggs were taken from the Raynham nest on February 18; the owl laid a second set, probably around the middle of March, in the same nest; there were two eggs in the nest on March 23 and on March 31; these eggs probably hatched around April 12. On April 14 the two young owls were but little larger than newly hatched chickens, they were well covered with pure white down, their eyes were not yet open, they were not able to hold up their heads, and were peeping feebly as they nestled under the warm fur of two cottontail rabbits, the fore-quarters of which had been eaten. On April 25 the owl flew from the nest when I rapped the tree, and the young owls, which were now abut two weeks old, were about one-third grown; the first coat of white down had been replaced by a coat of dirty, buff-colored down, mottled on the back with dusky; the eyes were open, and the irides were a pale, yellowish hazel. There was no food in the nest but a number of bones. One side of the nest had been beaten down considerably and was soiled with excrement, where the young had been unsuccessful in their attempts to cast it over the side; the odor was rather offensive. On May 5 the old owl was still brooding over her young, standing above them with ear tufts erected, but she flew before I reached the tree. The young were now heavily clothed in fluffy down; their eyes were light yellow, and their primaries were partially out of their sheaths. There was about half of a cottontail rabbit in the nest.
When I visited the nest on May 12, I was surprised to find it empty and considerably dilapidated; perhaps the young were forced to leave it prematurely, for they were only about one month old and would not be able to fly for at least five weeks more. After a short search, we found them huddled together on a rock at the edge of the woods, basking in the sun, two great, fluffy balls of down, hissing and bristling defiantly, if we came too near. I doubted if any fox or other predatory animal would dare to tackle them, as they looked too formidable and seemed well able to defend themselves. Their parents were watching them from nearby trees and were taking good care of them; they had been feeding on a black duck, of which only the bill, a few bones, and some feathers remained. Their wings were not much developed, and their tail feathers were only just bursting the sheaths. How they reached the ground in safety from that 40 foot nest is a mystery; probably their half-developed wings helped to break the fall, and they were tough enough to stand the shock. I never knew what became of them, for on my next visit I could not find them.
The other nest, in Middleboro, was a previous year's nest of a red-tailed hawk, 45 feet from the ground in a large white pine.When we visited the nest on April 7 the two young owls were apparently recently hatched, perhaps one and three days old; their eyes were not yet open, and they were scantily covered with creamy-white down; they were peeping loudly enough to be heard from the ground and were shivering with the cold. The nest was a large, flat platform of sticks, 28 by 36 inches, with no lining except the remains of the old pine needles formerly used by the hawks; piled up around the north side of the nest, as if to shield the young from the cold wind, were the hind quarters of six cottontail rabbits, the heads and entrails having been eaten.My next visit was made on April 14, when I found the young owls to be about one-third grown; they could move about in the nest somewhat, and were well covered with buffy, mottled down; their eyes were partly open and were light yellowish hazel. The nest was very dirty and smelled badly of decayed meat and general filth; the food supply consisted of three cottontail rabbits and the hind quarters of an American bittern. The old owls were in attendance, but not on the nest. On April 26 the young were fully half-grown and were about three weeks old; their eyes were now light yellow, and their primaries were bursting the sheaths. The nest contained the remains of a skunk and a cottontail rabbit, and on the ground below it were numerous black duck feathers. The young now showed fight, bristling up their downy plumage, spreading their wings, snapping their bills, and threatening to attack.
My last visit to the nest was on May 5, when only one young remained in the nest; the other was soon discovered, sitting on a fallen tree about 30 yards away. The young birds were much larger than when I last saw them, being more than four weeks old and nearly fully grown; their backs and wings were more fully feathered, and their tails were well started, but the rest of their plumage was mostly downy. The old owls were very solicitous and were keeping a close watch over their helpless young; but in spite of their protests, I carried off one of the youngsters for future study in captivity. I placed him in a roomy outdoor cage, with a sheltered compartment, where he lived in apparent contentment for more than two years, and might have lived longer if he had not been convicted of murder and executed. During the latter half of June his wings and tail became sufficiently developed for flight, though his body plumage was still principally downy. In July, he could fly, but it was not until October that he was fully feathered.
The whole nesting period for this species is much prolonged; the period of incubation has been estimated from 26 to 30 days, but it does not seem to have been accurately determined; Professor Keyes (1911) says that it is not less than 30 days, and probably more. Both sexes assist in it, but I suspect that the female does most of it. The young do not open their eyes for the first week or ten days; they are brooded by their parents for three or four weeks, perhaps more; they do not leave the nest normally until they are four or five weeks old; and they cannot fly until they are nine or ten weeks old. During all this time they are watched, protected, and fed by their parents. Beyond this they follow the old birds about, crying lustily for food, perhaps for many weeks, until they learn to hunt for themselves and are finally driven away, thoroughly weaned, to other hunting grounds far from the place of their nativity. Dr. Paul Errington (1932a) writes: "Where does the juvenile go, after it takes up a wholly independent existence? Of thirteen horned owl nestlings (birds that had never been tamed, tethered, or experimented with in any way to reduce their prospects for survival) personally banded in 1930 and 1931, three were reported shot within a year or so, all at points thirteen to twenty miles of where banded."
Clarence F. Stone, of Branchport, N.Y., tells me an interesting story of a pair of young owls that followed their parents about all summer, and even up to the latter part of October, in the vicinity of his camp. He writes: "Almost every night during the month of June 1932, just as the shades of night darkened the woods, two large owls, uttering harsh screams, the like of which I had never heard, came down through the gloomy hemlocks in the bottom of the gully and took perch on lumps of shale, or on the dead fallen trees still clinging to the perpendicular cliffs. In July they changed their route by coming around Chasm Lodge from the upper backwoods of pine and hemlock, where they took perch in the lofty pines and gave vent to rather terrifying and horrid screams. These two owl screamers traveled together, apparently hunting, and alternately uttering the loud, raucous screams that were evidently prompted by the urge of gnawing hunger. Almost nightly during this month, a pair of great horned owls came to hunt and hoot around the lodge. Invariably, a little time later, the two screamers gradually approached the hunting area of the hooting owls. Both the adult pair of hooters and the two screamers had two nightly sessions, first from just at dusk to near midnight and again just before the dawn of the day."
Again, on October 20, he writes: "As it was very rainy all the fore part of last night, the hideous screamers did not come to entertain me as usual, but at 4:30 o'clock this morning, I was awakened by the booming hoots of adult great horned owls, and a few minutes later I was fully aroused when the two ferocious screamers suddenly began their harsh yowls in the big pines over the roof of the lodge." On the evening of October 23 the four owls "went on a rampage" again, and he saw the young owls clearly enough to identify them as great horned owls, with well-developed ear tufts, and to see them giving their harsh screams "four to six times a minute." And he says, in conclusion: "In this instance, at least, it seems that the young owls of the year were yet, so late in October, partly dependent on, or at least following, the parent great horned owls about on their hunting excursions. At no time did I hear the adult owls utter anything but the hooting owl language. Only the young owls of the year shrieked the loud, harsh, blood-curdling screams. And I am inclined to believe that these harsh cries were simply hunger screams, characteristic of yearling great horned owls."
Plumages.--When first hatched the young owl is covered with pure-white down, only slightly tinged with grayish buff on the back and wings; this gradually becomes more generally grayish buff during the first week or two, when the secondary, buff, down begins to appear and is fully developed at three weeks of age, with some of the natal down adhering as white tips. This down is long, soft, and fluffy, especially on the thighs, "cream-buff" basally, paling to "cartridge buff" at the tips. Through this down the soft juvenal downy plumage gradually comes in, and this is worn in slowly diminishing areas all summer, or until it is replaced by the first winter plumage early in fall. This is somewhat darker buff, especially on the breast, and is barred with dusky, more heavily on the back and more faintly on the breast; it is long and fluffy, especially on the thighs and rump; on the head the down is short and soft, basally "cinnamon-buff," with pale tips and barred with dusky; the ear tufts are only faintly indicated, and there is much black or dark brown in the facial disks. There is much individual variation in the colors of this plumage, forecasting the color phases of the adult; and the various races show their racial characteristics to some extent at this age. In the meantime the first winter plumage has been pushing out through this downy plumage, first in the wings, then on the back, then in the tail, followed by the rest of the body plumage, and finally on the head. The primaries begin to burst their sheaths at an age of three or four weeks, but the wings are not fully grown until the bird is eight or nine weeks old. In my captive bird, the head, neck, and under parts were still largely downy at an age of 14 weeks; and the full plumage was not acquired until the bird was more than 20 weeks old in September.
This first winter plumage is much like that of the adult but is somewhat more rufous throughout, the ear tufts are smaller, the white throat patch is less extensive and not such pure white, and more or less of the downy plumage persists for some time about the neck and lower under parts. It is worn for ten months or so, until the next annual molt, the first postnuptial. Adults apparently have only one complete annual molt in summer and fall.
Food.--The great horned owl is a ravenous feeder on a great variety of animal life, and a very generous provider for its hungry young; almost any living creature that walks, crawls, flies, or swims, except the larger mammals, is its legitimate prey; it is not at all particular as to what it kills for food and will take what is most available and most easily caught. It is so powerful and aggressive that it can attack and kill surprisingly large mammals or birds. Where its victims are plentiful it often kills much more than it needs, eating only the choicest parts, but where food is scarce it often returns again and again to its kill.
I believe it prefers to feed on the smaller mammals, mainly those that are active at night, as these are more readily available and easier to catch in its favorite haunts than are birds and poultry; where these are sufficiently numerous, they make up the bulk of the food of this owl. The list of mammals taken includes hares and rabbits of various species, gray, red, flying, and fox squirrels, chipmunks, various rats and mice, including our destructive house species, muskrats, ground squirrels, pocket gophers, spermophiles, minks, weasels, large and small skunks, woodchucks, opossums, porcupines, domestic cats, shrews, and bats. Most of the records indicate that the cottontail rabbit is the most prominent item. Sometimes tracks in the newly fallen snow tell the story of the owl's hunting. Lewis O. Shelley describes it graphically in his notes as follows: "Here on a moonlight night of February, in an open glen away from the dark conifers and near the swamp, several rabbits meet to sport and play, and can be heard squealing, as they hop about and follow their paths at breakneck speed. As their play goes on, a shadow sweeps from the darkness of the hemlocks. And all the rabbits scatter, unmindful of their paths, or freeze in their tracks, their eyes wide, their hearts pounding. By daylight there will be this maze of tracks outside the beaten paths, where a rabbit has darted here and there without coherent thought of destination. At last you find where the tracks end in a circular arena. There are bits of fur, to be sure, but that is all. Yet you know that Bubo, the great horned owl, has dined to the full, back in the seclusion of the conifers; and Bubo leaves no tracks, only bits of fur and sometimes drops of blood."
The great horned owl's nest often smells strongly of skunk, and the birds themselves often retain this pungent odor long after they have been made into museum specimens. G. Norman Wilkinson (1913) relates the following:
One morning, late in the autumn, I was driving through the woods, when I heard a disturbance in the dry leaves at a little distance from the road. . . . As I drew near, I saw clearly the cause of the disturbance. A few feet in front of me was a large Horned Owl in a sort of sitting posture. His back and head were against an old log. His feet were thrust forward, and firmly grasped a full-grown skunk. One foot had hold of the skunk's neck and the other clutched it tightly by the middle of the back. The animal seemed to be nearly dead, but still had enough strength to leap occasionally into the air, in its endeavors to shake off its captor. During the struggle, the Owl's eyes would fairly blaze, and he would snap his beak with a noise like the clapping of your hands. Neither the bird nor his victim paid the slightest attention to me, though I stood quite close. How long since the Owl had secured the death grip I do not know, but there was no doubt about his having it. The skunk could no more free itself from the Owl's claws than it could have done from the jaws of a steel trap. Its struggles grew less and less frequent and at the end of about fifteen minutes they ceased altogether.
At least three cases have been reported of a horned owl tackling a domestic cat. In one case, the owl found that it had "caught a Tartar," for the cat put up a stiff fight and had to be dropped. Oliver L. Austin, Jr. (1932), tells of a more successful attempt:
I flushed a Great Horned Owl, which fluttered up in front of my car and flew laboriously down the road. The headlights showed it to be carrying something heavy, something which it could not lift two feet off the ground. I gave chase, and the bird dropped clumsily a hundred yards farther on, to crouch defensively atop the prey it seemed so loath to leave. I stopped the car twenty feet away and turned on my strong spotlight. The owl's attention was riveted by the dazzling beam, and while it stood motionless staring into the glare, I crept up cautiously on the dark side, threw my jacket over it, and pinioned it down. After wrapping the claws in my handkerchief to prevent accidents, and folding the bird safely in my jacket, I stooped to pick up its prey, which to my surprise proved to be a half-grown house cat. The kill evidently had just been made, for the limp body was still warm and quivering.
Another dangerous animal for this owl to tackle is the porcupine; a strong dose of the barbed quills of this animal might eventually result in the death of the owl. Rev. C. W. G. Eifrig (1909) had one of these owls brought to him that had tackled a porcupine. "It was liberally sprinkled over with quills, especially on the sole of the right foot--the quills having penetrated even that horny skin--under the right wing, on the breast, neck, and even two in the left eyelid. Some of the quills had pierced the thick, solid muscles of the breast, lying against the sternum. Fifty-six quills and parts of quills were extracted from the skin and flesh, and about ten left in."
The list of birds eaten is a very long one and contains many large species, which are probably attacked under great stress of hunger. It includes pied-billed grebe, several species of wild ducks, Canada goose, tame ducks and swans, American bittern, small herons, American coot, Florida gallinule, king and Virginia rails, red phalarope, Wilson's snipe, yellowlegs, woodcock, various quail and grouse, pheasants, domestic poultry (including turkeys, hens, guinea fowl, and pigeons), mourning dove, marsh, Cooper's, red-tailed, and red-shouldered hawks, barn, barred, long-eared, and screech-owls, flickers, sapsuckers, and other woodpeckers, blue jay, crow, starling, blackbirds, meadowlark, snow bunting, junco and other sparrows, mockingbird and robin.
Great horned owls often visit duck stands and kill the decoy ducks and geese that are tethered on the beaches. They kill also large numbers of grouse in our northeastern forests; I have often found the remains in their nests and evidence of their numerous kills scattered through the surrounding woods. Mr. Shelley says in his notes: "A great horned owl killed a cock ruffed grouse in a piece of woods 50 yards from the house. The grouse was almost entirely and neatly plucked, this being done in two locations 20 feet apart. At the first spot all the small body feathers were stripped off, and at the second spot the wing quills and tail feathers. Here the bird was eaten, and only a few small pieces of broken bone were to be found in the feather refuse. Again, early in the morning of April 23 (six days later), a hen grouse was found about 400 yards from the first killing, also prey of probably the same owl, which is rare here at any season. This time the grouse had been plucked neatly in two locations 12 feet apart; at the latter spot the body had been carried 5 feet farther and placed behind a fire-charred stump after the head, the meat of one leg, and most of the viscera had been eaten. Early in the morning of the 24th, the owl returned to its cache, dragged it to a new spot 10 feet distant, and there completed eating the carcass."
I once had a captive horned owl that I had raised from the nest and kept in my aviary with several other hawks and owls; in the nest cage, separated by a chicken-wire partition, was a pet red-shouldered hawk, of which I was very fond, as it would eat out of my hand; one night the owl broke through the partition, killed and partially devoured my pet hawk; the owl soon paid the penalty of a murderer and is now in my collection.
In the middle of a bright day in April, while we were hunting for nests of the red-tailed hawk in the woods of Plymouth County, Mass., we saw a pair of these hawks sailing about over a large tract of pitch-pine timber, half a mile or so distant. Half an hour or more elapsed before we began a systematic search for their nest, when only one of the hawks was seen, circling back and forth over the woods and evidently looking for something. We had not gone far into the pines before we saw a great horned owl fly from a small pitch pine; on closer inspection, we saw a great mass of feathers on a flat branch near the top of the tree; it was apparently the owl's feeding roost, as there were feathers and droppings on the ground beneath. I climbed up to investigate it and was surprised to find the wing of an adult red-tailed hawk which had recently been torn from the body of the victim; the flesh was still fresh and warm. I had no doubt that the owl had just killed one of the hawks that we had seen sailing over the woods less than an hour before.
At least two other similar cases have been reported. Arthur H. Norton (1928) found even more convincing evidence on a nest of the owl that he was studying in Maine; he says: "On the side of the nest rested the wing of a large bird; this proved to be the wing of a red-tailed hawk which had been eaten by the family; feathers were scattered all about the tree, and a mass of other feathers on a bare ledge about seventy feet east south east from the nest showed the place where the victim had been throttled or partly plucked. The wing proved to have been stripped of flesh; and later the legs were found, one in the nest, the other near the crest of the ridge a hundred or more feet to the north north east from the nest, both with the flesh stripped off."
The list of miscellaneous food includes snakes, frogs, dace, goldfish, bullheads, eels, perch, crawfishes, Jerusalem crickets, beetles, grasshoppers, katydids, and scorpions. Mr. Forbush (1927) tells of a man who "came upon a Horned Owl in trouble with a black snake. . . . Plainly the owl had caught the snake, but the reptile had twisted itself around the bird so that it was unable to fly, and fell to the ground with its prey. . . . The owl had grasped the snake about six inches below its head, but the part of the snake below the owl's talons had twisted itself around the bird tightly. There was at least one light turn around the owl's neck." The snake was killed, though neither antagonist had given up the fight, and "the owl was so weakened and helpless that it could not fly; it seemed to have been choked."
S. A. Grimes (1936) gives an interesting account of struggle between a great horned owl and a large black snake, 46 inches in length. He found the owl "lying on its side with its wings outspread, trying its best to get its talons on a black snake that was coiled around the bird's abdomen just back of the breast bone and beneath the wings. The snake had gotten itself around the owl in a double coil. Six or eight inches of its head and neck and perhaps a little more of its tail were free, but the bird appeared to try only to get hold of the strangling coils around its body. It is easy to see that the bird could not possibly get its talons on that part of the snake tightly wound around its abdomen, but why the hooked bill was not brought into play is hard to understand." The owl was plainly exhausted but was able to make a feeble flight for about 100 yards, with the snake dangling, and alight on a stump. As Mr. Grimes approached, the owl flew again and alighted on a log in a small pond, where a charge of shot ended the career of both combatants. The owl had evidently attacked the snake, and the slippery reptile, noted for its agility, had somehow eluded the formidable talons and quickly coiled itself around the body of the bird.
The great horned owl, like some other birds of prey, often has a regular feeding roost, to which it brings its prey to be torn up and devoured. This may be an old, unoccupied nest, a wide, flat branch of a tree, the hollowed top of a stump, or a hollow place on a fallen log. Such places are profusely decorated with the remains of feasts, feathers, bones, fur, pellets, and droppings; they are usually not far from the nesting sites.
Studies of pellets made by Mrs. Bessie P. Reed (1925) showed that they "were usually coated with a thick layer of mucus and never contained any other material save feathers, hair, fur, and cleanly polished bone. . . . Microscopic evidence showed that hair and feathers were in no way affected by the digestive juices, although the quills of large feathers were always splintered and rolled together. On a number of occasions pellets were found that contained hair of two different colors or hair and feathers in which the masses were not mixed at all but were very sharply delimited, indicating that two portions swallowed at different times were not mixed together."
When small birds or mammals were fed to her captive owls, "feathers, hide, and fur were always swallowed, the plucking or skinning process being evidently accomplished in the owl stomach. These, along with the bones, were rolled into a compact mass and afterwards regurgitated, usually in about twelve hours. When living on an exclusive diet of raw meat from the butcher shop for a few days the birds readily devoured feathers from a plucked chicken in considerable quantities."
That this owl can be a powerful factor for either good or evil, is illustrated by the great quantities of food brought to the nest; I once saw six cottontail rabbits in a nest at one time; Major Bendire (1892) reports a nest that contained "a mouse, a young muskrat, two eels, four bullheads, a Woodcock, four Ruffed Grouse, one rabbit, and eleven rats. The food taken out of the nest weighed almost 18 pounds."
The economic status of the great horned owl depends almost entirely on its surroundings and the kind of food available and its abundance. I am not sure that, generally speaking, it is nearly so harmful as is generally believed; and, in some places, it is certainly more beneficial than harmful. Where rabbits and other small mammals, which it seems to prefer, are scarce, it is forced to live largely on birds and domestic poultry; and probably some individuals develop the poultry habit. Robert Little (1931) reports a case of this; he trapped one of these owls in an extensive poultry yard, and says: "The trap was set in open ground near the chicken pens and was baited with a live pullet tethered to a stake. A few nights before, a small night-box in one of the yards, faced with chicken-wire, had been entered, and 106 pullets (nearly all the box contained) had been killed and left dead. The birds were pierced through the back with what were considered to be talon wounds. . . . A turkey hen also had recently been killed and lesser depredations had been committed."
Raids like this and lesser damage to poultry have given this owl a bad name; but we must make allowance for the fact that such cases are oftener brought to our attention than are the good deeds of the owl in destroying harmful rodents. Furthermore, there have been numerous cases recorded where great horned owls have lived and raised a family in close proximity to farms and poultry yards without molesting the poultry at all, and with no signs of poultry found in their nests.
As to the effect on game birds, Dr. Errington (1932a) writes:
The Wingra situation, contrasted with that of the Hammersley Slough area, illustrates the bearing of plentiful "buffer species" on the diet of a versatile predator. Up to a hundred Mallard ducks frequented shore-line springs of the refuge all winter, and the lone owl's territory was cohabited by three large covies of quail, yet he was known to get but two (and one of these kills was not unquestionable) quail and no ducks during a four month's sojourn. Why? Because the refuge was overrun with rabbits, and Bubo had slight need of ranging very far in quest of something to eat. On the other hand, the owls of no. 24, finding comparatively "lean pickings" near home, had to take almost anything they could get.
Mr. Forbush (1927) writes: "European Hares had been introduced by someone in eastern New York near the Massachusetts line and had increased rapidly in numbers and spread into western Massachusetts where they had become a serious pest to the farmer and orchardist. In November and December of 1919 a flight of owls came into that region and Mr. Walter Pritchard Eaton told me that numbers were heard about the mountain in Sheffield. There they preyed upon the hares. . . . These owls overran the region and many returned the next winter. The following spring European Hares were very scarce in that country."
To illustrate the value of the great horned owl as a ratter, H. A. Surface (1904) published part of a letter from O. E. Niles, from which I quote as follows: "In the nest where he captured the young owls he noticed several full-grown Norway rats, with their skulls opened and the brains removed. On descending to the ground he also noticed the bodies of many rats around the tree, and out of curiosity counted them, and found the bodies of one hundred and thirteen rats, most of them full grown. They all appeared to simply have had their skulls opened and the brains removed; and from their undecayed appearance, must all have been captured within the previous week or ten days."
Behavior.--The silent flight of the great horned owl is powerful, swift, and graceful. When leaving a perch, it flaps its great wings heavily and rapidly, with its feet dangling; the feet are soon drawn up into the plumage and the wings spread, as it glides swiftly away for a long period of sailing on fixed wings. It threads its way with perfect precision through the branches of the forest trees, or glides at low levels over the open meadows, where it can drop swiftly and silently on its unsuspecting prey. I have several times seen it soaring high in the air on a bright day, with all the grace and power of an eagle or a large Buteo, for its eyesight is perfect, and it hunts by day as well as by night.
The strength and endurance of this owl, as well as its failure to learn by experience, are illustrated by a case reported by Dr. Sutton (1929a); an owl was caught in a steel trap but flew away with the trap, which was not securely fastened; two days later the owl was caught by the other foot in another trap set on the same post. Rev. J. J. Murray writes to me of a similar case: "A farmer, who had been losing his chickens and turkeys, set some steel traps in his chicken yard. Hearing a commotion one night, he got out to the hennery just in time to see a large owl fly away with a trap, the chain having been broken by its struggles. A week later the owl returned and the same thing happened, the owl departing with a trap on the other leg. It was later seen flying about with both traps. But, so handicapped, it managed to live and hunt for several weeks, until one of the chains caught in a fence and the bird was killed.
Although, during the season when they have to supply an extra amount of food for the young, these owls are forced to hunt some by day, I believe that at other seasons they prefer to spend the day in seclusion; the thick tops of evergreen trees are favorite daytime roosts; here the owl sits, close to the trunk or among dense foliage, preferably within its breeding territory, its eyes closed to narrow slits, its ears erected, and its body plumage contracted to the tall, narrow, hiding pose assumed by other owls; its colors and its shape make it quite inconspicuous in such a situation. Dr. Errington (1932b) writes: "The trees favored were those to which leaves clung during the winter, those the tops of which were entangled with vines, those with broken hanging tops, or those otherwise promising sanctuary to owls not desirous of spending the daylight hours in the entertainment of crows."
The behavior of great horned owls in the vicinity of their nests varies greatly with different individuals, though it is generally hostile, especially when there are young in the nest.
One pair that I visited twice, while they had young, never showed themselves at all. On other occasions the owls have generally been much in evidence, and more or less threatening in their behavior, flying about near the intruder, alighting in nearby trees, snapping their bills, and hooting. Once I was savagely attacked, while I was climbing to a nest in which the eggs were hatching. I had hardly climbed ten feet on the big pine tree, when the great brown bird glided past me and alighted in a pine beyond. There she sat, glaring at me, swaying from side to side, her wings partly spread, her plumage ruffled out, looking as big as a bushel basket, her ears erect, and snapping her bill furiously, a perfect picture of savage rage. As I continued upward her mate soon joined her, and then followed such a demonstration of angry protest as I had never seen; they flew from tree to tree, dashing past me repeatedly, too near for comfort, snapping their bills, and hooting constantly in deep, subdued tones, kr-r-r-ooo-ooo, krrooo-ooo. Only once did they give their regular hooting call.
Once, when I was not looking, I felt the swoop of powerful wings, then a terrific blow on my shoulder, almost knocking me out of the tree, and I could feel the sharp claws strike through my clothes. Several times I had to dodge from the furious attacks. As I neared the nest, I felt a stunning blow behind my ear, which nearly dazed me, and off sailed my hat a hundred feet away; her sharp talons had struck into my scalp, making two ugly wounds, from which the blood flowed freely. This was the limit; I did not care to be scalped, or knocked senseless to the ground, so down I came, leaving the owls the masters of the situation. I visited the nest the next day, with a cameraman to photograph the performance, but the owls failed to repeat their attacks.
I have since learned that my experience was not unique. I find in the literature reports of numerous similar attacks on men at the nests. Professor Keyes (1911) says, of a blow that he received: "It came absolutely unexpected and was so violent as to leave the left side of my head quite numb. . . . The slash which began on the left cheek and ran across the left ear was rather ugly but not dangerous. . . . Three times on this occasion one of the birds flew in from a neighboring tree and with strong stroke of wing came straight at my head. It was not at all the stoop of hawk or falcon, but rather the onrush of a heavy projectile with a very flat trajectory. Like a large projectile, too, the flight was visible and so all the more disconcerting; unlike a projectile, it was noiseless as a flying shadow."
Donald J. Nicholson (1926) received even rougher treatment when he climbed to within 6 feet of a nest containing eggs; he writes: "Swiftly the old bird came straight as an arrow from behind and drove her sharp claws into my side, causing a deep dull pain and unnerving me, and no sooner had she done this than the other attacked from the front and sank his talons deep in my right arm causing blood to flow freely, and a third attack and my shirt sleeve was torn to shreds for they had struck me a third terrible blow on the right arm tearing three long, deep gashes, four inches long; also one claw went through the sinew of my arm, which about paralyzed the entire arm."
Attacks on human beings at other times have been reported several times; a man, moving about at night near the haunts of the owl, is likely to be struck on the head, especially if he is wearing a light-colored cap or one made of fur, which the owl may mistake for some kind of prey. Forbush (1927) tells of one that struck the claws of both feet into the back of a large collie dog. "This bird may have been misled by a white patch on the dog, as the white on the back of a skunk is its favorite mark."
Others have noticed a strange behavior at the nest, which is common with the long-eared owl, but which I have never seen in the great horned. Ralph W. Jackson (1925) describes it as follows:
As I was climbing the tree to examine the young, which were visible from the ground, I heard short wailing notes to one side and arising apparently from the ground. . . . When about thirty-five feet up, I was surprised to see one of the owls half running and fluttering some fifty yards away on the floor of the woods with wings outstretched and uttering the notes that I heard a few moments before. Occasionally the bird would stop, beating first one wing and then the other, as though wounded. Twice the bird left the ground perching in the tops of nearby trees and then the well known "hoot" was heard, which is the usual form of protestation. In each instance, after a few moments' inspection, the bird returned to the ground and continued the fluttering actions which lasted while I was in the vicinity of the nest."
Dr. Errington (1932a) has noticed similar behavior on three successive years by what he believes to be the same owl.
There is abundant evidence that the eyes of the great horned owl are admirably adapted for effective use in either darkness or bright light. Dr. Elliott Coues (1874) says of his captive owls:
Their vision was acute at all hours. I often saw them look up and follow with their eyes the motions of a grasshopper or butterfly, flickering several yards up in the air. On one occasion in particular, I saw them both gazing steadfastly, and on looking up to see what had attracted their attention, I was myself blinded by the glare, for the direction was exactly in the sun's eye. But a few moments afterward I discovered a pair of white Cranes, floating in circles half a mile high. The Owls' eyes endured a glare that my own could not, and the birds certainly saw the objects, for they slowly moved the head as the Cranes passed over. . . . Nor was the inner eyelid drawn over the ball to shade it. I had abundant evidence, on this and numerous other occasions, that the movements of the bird's iris are entirely under the control of the will, instead, as commonly supposed, of being automatic, depending upon the stimulus of light. I frequently saw them instantaneously contract or relax the quivering iris in accommodating their vision to different objects, or different distances; and, moreover, they could move the two irides independently of each other.
Hearing is exceedingly acute in these and other owls. Mrs. Reed (1925) says of her captive owls: "It was almost impossible to surprise any one of them in the shed although the approach was made as cautiously as possible from the side where no glimpse of the observer could be obtained. Not only was it possible for them to hear the slightest sound but they could readily localize it. Experiments were made where the observer, concealed, gave various sounds and each time the direction was detected. A tapping on the attic window when one of the captives was perched at the pen side of the shed invariably brought a response, the one in question focusing its vision at the origin of the noise."
She seems to agree with Frank Bolles that the sense of smell is not highly developed in these owls; her birds disliked putrid meat but always tasted it before rejecting it. Mr. Shelley, on the other hand, says that he has seen owls caught in traps "where the meat was wholly concealed by refuse and the bird could have been interested only by the musky odor permeating from fresh muskrat carcass."
Great horned owls seldom make satisfactory pets. The one that I raised from a nestling and kept for over two years never became tame; it was always sullen and ugly; it would fly in a rage at any stranger that entered its cage, and often at me.Three of Mrs. Reed's owls made gentle and responsive pets, though no special effort was made to tame them; they would come in response to her call and alight on her arm, even when given full liberty. But the fourth, in spite of her efforts to tame it, was always "surly, sullen and morose," utterly untameable and vicious. Others have had some failures and some successes. Dr. Errington (1932a) says: "The first two weeks in the young horned owl's life have a singularly profound effect upon its future disposition. Recently hatched owlets accustomed to no source of food other than their human attendants came to recognize them somewhat as they would their own parents, even displaying what appeared a great deal like true affection. On the other hand, an owlet reared by its parents through approximately one-fourth of its growth never did really tame, though it tolerated discreet handling."
Otto Widmann (1907) had a male in captivity that lived for 29 years; but, after he had had a mate for seven years, he killed and partially ate her. Harold M. Holland (1926) tells a remarkable story of a female that was still living after 19 years in captivity; when she was seven years old she laid two eggs; these were removed, and hen's eggs substituted for them, which she incubated and hatched, and afterward brooded the young as if they were her own. "Every year thereafter, in February or the fore part of March, eggs have been laid, the clutch never exceeding two, although sufficient time for a third was allowed, and as often has followed the substitution of hen's eggs. And each returning spring has witnessed the bringing forth and mothering of young by this faithful bird."
Voice.-- The hooting of the great horned owl is, according to my experience, entirely different from the vehement, strongly accented, and spectacular hooting of the barred owl. It is on a lower key, deeper bass, and softer, but has great carrying power. I have likened it in my notes to the sound of a distant foghorn, the far-away whistle of a locomotive, or the barking of a large dog in the distance. At times, when near, it has seemed more like the cooing of a dove than the hooting of an owl. The ordinary note, when the owl is not excited, is a prolonged, soft, somewhat tremulous, and subdued hoot, with little or no accent, whoo-hoo-ho-o-o, or, longer, who-ho-o-o, whoo-hoo-o-o, whoo. A still softer, cooing note sounds like hoo-ooo-ooo-ooo.
Once, when the owls were somewhat excited and young birds were in the nest, the hoot was preceded by a short bark, wa'-hooo-oo-oo-oo, but the bark was not so strongly accented as that of the barred owl. Again, when the owls were greatly excited, I recorded a more strongly accented hooting, whoo'-hu-hoo', hu-hoo'-hoo', whoo, or, shorter, hu-hu-hoo-ho'oo; the short notes were rapidly given, and the whole was in the usual soft tone. While the owls were attacking me, referred to above, they uttered angry, growling notes, which I recorded as krrooo-ooo, but I have never heard the blood-curdling screams that others have described. There is a sexual difference in the notes, the voice of the supposed male being pitched on a lower key, perhaps three or even four half-tones lower; his notes are more prolonged and elaborate, rich, deep, and mellow; hers are usually shorter, simpler, and softer.
I once watched a female hooting at short range, while I was at the nest. She was perched on a tree within ten yards of me, bristling up her plumage, with half open wings, snapping her beak, and hooting softly. She generally leaned forward in a nearly horizontal position while hooting, and I could plainly see the vibration of her white throat. Once she became more excited and gave a louder, more vehement laughing note, wha, whaart.
Mr. Shelley writes to me of an unusual demonstration that he heard one night, while he was out coon hunting: "There were three birds at least, and their increased hooting and following display may have been occasioned by some of our flashlights, as we approached and attempted to spot the birds themselves. Anyhow, their ordinary hooting was changed to weird, hollow-toned, and idiotic laughter. They flapped from tree to tree with much noise and gave a chuckling noise meanwhile. There were variations in the hooting: Whoo-who-who-whoo-who-who-oo-oo, one would call; and another, whar, who, whar, oo-who-o-o-o-ooh, ending in a throaty chuckle. And they would make a great din flapping their wings. One particular bird liked best its eerie and idiotic laughing call, depicted by the following phrasing: Whar, whah, wha-a-a-a-ah, the accent on the last syllable of each whah; it had a carrying quality similar to the water-pumping note of the bittern."
Mr. Norton (1928) heard a variety of other notes from the female of the pair he was watching, such as "ank?; ank?; ank?; in a key higher than her usual one. . . . Sometimes she called in a hawk-like note, ke-yah, ke-yah. . . . The female called twice from the nest, in feeble tones, erk, erk. . . . From the direction of the nest a meow like that of a cat was heard."
Many other observers have given somewhat similar renderings of what were probably the same notes that I have attempted to describe above. But I suspect that some unusual notes, ascribed to this owl, have been those of the barred owl, wrongly identified. Clarence F. Stone tells me that the loud, harsh, blood-curdling screams referred to above are the food calls of the yearling young, heard through the first summer and fall, and are not uttered by adults.
William Brewster (1936) says of a young owl that he had in captivity: "At intervals from one to five minutes during the night and occasionally by day, as well, it uttered a short, harsh, penetrating cry which was not unlike the peep of Chordeiles and which, no doubt, was merely a variation--perhaps characteristic of very young birds--of the Jay-like cry that I hear every autumn at Lake Umbagog. I suspect that by means of this call it finally attracted the attention of one of its parents."
Field marks.--The great horned owl is the largest of the common resident owls of the United States, somewhat larger than the barred owl, darker in color and brown rather than gray; some of the paler races are quite light colored, but they are found in regions where the barred owl does not occur; they are paler than the spotted owl but considerably larger. In all the races the wings seem very long and broad in flight, and the ear tufts are very prominent when the owl is perched. At short range the white throat patch is conspicuous and the large yellow eyes may be seen. In flight the ear tufts are flattened and do not show, but the large head and short neck are distinctive.
Enemies.--Horned owls have plenty of enemies that cordially hate them, but none of them are dangerous, except man and occasionally one of their own species. Crows are their chief enemies, with blue jays a close second and all other small birds following. I have often been able to locate an owl by the clamor of a noisy and excited mob of crows. If an owl is discovered by a crow, the alarm is immediately given and all the crows within hearing respond to the call, gather about the owl, flying around and perching in the tree as near to the owl as they dare go, cawing loudly and making a great fuss. They seldom are bold enough to strike the owl, though I have seen them do so twice. The owl stands all this with dignified indifference, until his patience is exhausted, when he flies away with a string of crows trailing on behind; perhaps he has to move several times before he shakes off his tormentors or finds a secluded hiding place, where he can doze in peace. The owl seldom retaliates by striking one of the black rascals; in fact, I doubt if he ever does. But he gets even with them when they are in their roosts at night; I have heard of several crow roosts that were broken up by a great horned owl living in the vicinity; and many an owl has eaten crow.
Horned owls are sometimes attacked by the larger hawks in contests over nests, but the owl usually wins. On a Louisiana highway that had been open only a few weeks, William B. Ward (1934) found, on a 10-mile stretch of road through a swamp, 17 large owls that had evidently been killed by automobiles.
Winter.--Horned owls are often said to be permanently resident throughout their ranges, but this is true only in the more temperate regions. When the snow is deep and game is scarce in Canada, we may look for heavy flights of northern owls to more congenial winter hunting grounds. Arthur W. Brockway (1918) reported a heavy flight at Hadlyme, Conn., in November and December 1917; a game keeper there trapped 91 great horned owls during the fall and winter.
Referring to the same flight, J. Dewey Soper (1918) says: "The point of interest lies in the fact that the Horned Owls were apparently absent from the north country at the time of my trip October 20 - November 6; common on my return to Preston, Ont., November 7, and apparently so at other points in southern Canada." Mr. Forbush (1927) mentions other similar flights. He says also: "Mr. H. A. P. Smith writing from Digby, Nova Scotia, March 14, 1923, says that a Great Horned Owl was found there sitting upright in an apple tree frozen stiff. Probably his tightly clinched talons froze to the limb and held him there in death; but the bird would not have been frozen had it had food enough to keep up the animal heat in its body."
Dr. Errington (1932a) writes:
Prior to 1932, it was noted casually that horned owls were apt to station themselves in the fall in the near neighborhood of old stick nests (hawk or crow) which they would appropriate in the spring. During the season of 1931-1932 this was checked up more carefully. In the late fall, 1931, five horned owl territories were discovered in regular use (judged by birds seen and by accumulations of feces and pellets beneath roost trees), of which four proved to be nesting areas.
Three other nesting areas, not actually visited in the fall,
betrayed by old pellets their early occupancy. Exception: one pair
did not move into their nesting territory until January or later,
though breeding was not delayed, as incubation had started by
February 21, 1932.
Great Horned Owl* Bubo virginianus
*Original Source: Bent, Arthur Cleveland. 1938. Smithsonian Institution United States National Museum Bulletin 170: 295-322. United States Government Printing Office