[Published in 1938: Smithsonian Institution United States National Museum Bulletin 170 (Part 2): 243-258]
Because the Linnaean name Strix asio was based on Catesby's "little owl" from South Carolina, our familiar screech owl of the northeastern United States has to be given the above new name, which is based on the name that Pennant gave to the "mottled owl" in his Arctic Zoology.
This species, as represented by its various races, is widely distributed from extreme southern Canada throughout practically the whole of the United States and well into Mexico. It is fairly common and well known throughout most of this range. As the eastern race enjoys the widest distribution and is the best known, it will be treated more fully than the other races, all of which are much alike in general habits.
Courtship.--Many of us have heard the tremulous and lugubrious wailings of the screech owl during the mating season, when this and the other owls are most active in their vocal performances; but, because these demonstrations of affection are indulged in mainly during the hours of darkness, few of us have ever seen the birds in action. Dr. Lynds Jones was more fortunate, and wrote to Major Bendire (1892) as follows:
I saw this species mating once. The female was perched in a dark leafy tree apparently oblivious of the presence of her mate, who made frantic efforts through a series of bowings, wing-raisings, and snappings to attract her attention. These antics were continued for some time, varied by hops from branch to branch near her, accompanied by that forlorn, almost despairing wink peculiar to this bird. Once or twice I thought I detected sounds of inward groanings, as he, beside himself with his unsuccessful approaches, sat in utter dejection. At last his mistress lowered her haughty head, looked at and approached him. I did not stay to see the sequel.
F. H. Carpenter (1883) had a pair of screech owls that raised a brood of young in captivity; he writes: "About the first of February, 1883, their actions towards each other began to change. Instead of snapping at one another for a bit of meat, I was surprised to see one of them take a bit of food and carry it to the other one that was perched on the topmost beam, which in turn gravely received it. . . . These attentions seemed to increase. They would sit as close together as possible, frequently preening each other's feathers. The male bird (I was sure of it by this time) would take a piece of meat and fly up with it to his companion, lay it down, and invite her to take it by a series of hops and bows."
P. T. Coolidge (1906) gives the following account of it:
About ten or eleven minutes after sunset he left the tree and began singing his love song; he was now full of life and ignored all disturbance. His song was in B flat of the middle octave, a soft trill, seemingly far away, two or three seconds long, and closing with an upward inflection, as if the bird were asking a question--as doubtless he was. Until the flight of the female, he sang from various perches, now from the branches of the elm, now from some neighboring tree, now from the rim of the cavity in the elm, his eyes fastened upon his quiet mate. His handsome head was continually bobbing and swinging. Once in a while the male would light beside her; flashing of wings would follow, but darkness made more exact analysis of their movements impossible. Occasionally he would fly out of sight. Returning from one of these trips, he lighted upon the rim of the cavity and touched his bill to that of his mate, but whether to give her some tidbit, or merely a greeting, the darkness kept secret.
Nesting.--Although the screech owl is fairly common in my home territory, I have never examined many nests, as I have never made any special effort to find them. On only one occasion have I been able to flush one of these owls off the nest by rapping on the tree; had I taken the trouble to climb to and examine every likely looking hollow, I probably would have found many more. As it is, my notes contain the records of only seven nests. Three of these were in natural cavities in old apple trees in orchards; two were in dead pine trees, and one in a dead poplar, in what where apparently old flickers' holes; and the other was 35 feet from the ground, the highest I have ever found, in a natural cavity in a large oak on the edge of some woods. I found my first nest on May 18, 1889, while climbing to an osprey's nest on a dead pine stub in some mixed woods; the owl's nest was in an old flicker's hole below the osprey's nest and about 20 feet from the ground; the owl was sitting on a set of five eggs nearly ready to hatch, and had to be lifted off the eggs. On April 12, 1891, we found a pair of screech owls, a red and a gray bird, nesting in a natural cavity in an apple tree in an old orchard; the opening was only about 5 feet from the ground, so that we could look in and see both owls in the nest apparently sound asleep; under the red owl were five fresh eggs. After removing both owls, to inspect the nest, we returned the gray bird to the hollow, where it promptly settled down; the red one we threw up into the air; it dove straight for the hole, but missed it and fell to the ground, perhaps bewildered by the light and the rude awakening; but it soon recovered its wits and flew off to some nearby woods. On two other occasions I have found both of a pair of owls in the nest together, always one red and one gray.
Two other nests in old orchards were evidently successive nestings of the same pair of owls. The first was found on May 20, 1933, in a natural cavity in an apple tree, about 20 feet from the ground; it contained five young, partially clothed in the downy juvenal plumage, that were being brooded by a red adult; when I released her, she flew swiftly and easily to another apple tree and dove into a cavity. We explored this orchard thoroughly on April 19, 1934, but could find no trace of the owls; but in another old orchard, about 200 yards away, we were more fortunate. An upright branch, or fork of the main trunk, of an old apple tree had an open cavity, facing upward; looking downward into this we could see the gray owl clinging to the rough side of the cavity and sound asleep; about 30 inches below the open cavity was a knothole, barely large enough to admit my hand; this was only about 6 inches above the nest of leaves and rubbish, on which we could dimly see the red owl, sitting on her eggs, blinking and snapping her bill. I succeeded in relieving her of six, nearly fresh, eggs; she made no resistance, as I reached under her, but finally climbed up and clung to the side of the cavity below her mate.
All the above nests were in Bristol County, Mass. In most cases the eggs were laid on the rotten chips and other rubbish that the owls happened to find in the cavities; I believe that they never carry in any nesting material and that where such material is found it merely indicates that some other bird or mammal had brought it there previously. But the nests often contain a few feathers of the owls, or the feathers, fur, or other remains of their victims. Though I do not claim that it has any great significance, it is an interesting fact that it has always been the red bird, in a mixed pair, that I have found sitting on the eggs, or brooding the young.
The above nestings were apparently typical of the nesting habits of the screech owl in other sections. A. D. DuBois writes to me of a nest he found, about 50 feet from the ground in a large sycamore; the owl sat with its head out of the hole, watching him, until he climbed to within ten feet of the hole; this habit has been noted by others. Major Bendire (1892) says: "Mr. Oliver Davie mentions his having found several nests between the broken siding of ice houses along streams. Mr. C. S. Brimley found a set of three eggs of this species placed in a cavity of a stump, the bottom of which was below the level of the ground outside."
Screech owls have been known to nest in bird boxes, set up for that purpose on trees or buildings, and they would probably do so oftener if given more encouragement; a little sawdust or excelsior in the bottom of the box is quite to their liking. They have also nested in dove cotes and in purple martin houses, and not always to the injury of the rightful occupants, as the following experience, related by Ralph R. Wilson (1925) will show:
During the winter of 1923-24 two Screech Owls took up their quarters in one of the roomy compartments of the largest nest-box. I was away that winter and the following spring, but when school closed (May 26) I returned and found ten Purple Martins nesting in the boxes. Three days later, at twilight, I saw a gray phase Screech Owl frequently alight at the entrance of the compartment of the largest nest-box and quickly fly away after a very noisy reception from within. I was surprised at this as Martins were nesting in all the other compartments.
Investigation next day disclosed a husky young Screech Owl, apparently the last of a brood, in the box. It was observed that the Martins carefully avoided that compartment. Ten days later the Owl was gone and a pair of Martins at once built a nest in and occupied that part of the box.
By June 30 the Martins were all scouring the air and feeding their young. That evening one parent Owl reappeared at the box. I scared it away but next day I noticed that the two Martins that nested where the Owl had nested were not feeding their young. A second inspection showed an empty nest.
The screech owl also has been known to nest frequently, even regularly, in cavities in trees close to houses in towns and cities, thus showing more confidence in human beings than most other owls show. I have had several such cases reported in my home city.
Eggs.--The screech owl lays three to seven eggs, but usually four or five, with the average in favor of five; the extremely large or small sets are rare; even as many as eight or nine have been reported, but these reports seem doubtful. Bendire (1892) says that they "are pure white in color, usually oval or nearly globular in shape, and moderately glossy. In the majority of specimens the shell is smooth and finely granulated, while in a few it is rough to the touch."
The measurements of 56 eggs in the United States National Museum average 35.5 by 30 millimeters; the eggs showing the four extremes measure 38 by 31, 37.5 by 32, 32 by 29.5, and 33 by 28.5 millimeters.
Young.--The period of incubation is variously reported as from 21 to 30 days, but the average is probably around 26 days, as determined by the careful observations of Miss Althea R. Sherman (1911). As the eggs are laid at intervals of two or three days, sometimes at longer intervals, and as incubation may begin after the first egg is laid, or not until after two or three are laid, the exact period of incubation is difficult to figure.
Apparently the female does most, if not all, of the incubating and the brooding of the young. Miss Sherman (1911) describes the egg laying and incubation as follows:
The first egg was found in the nest on the morning of March 27, and was still alone on the evening of the 29th. The following day the nest was not visited, the only day in two months and a half, when visits were omitted. No doubt the second egg was laid some time on the 30th of March; the third one was deposited on April 1, but two days intervening between the laying of the second and third eggs, while three or more days were the period between the other layings. The fourth egg was in the nest at half past four o'clock in the afternoon of April 4, but it was not there at eight o'clock on the previous evening. This shows that it took from eight to nine days to complete the clutch of four eggs. Whether the Owl laid in the night, or in the morning as other birds do, was not ascertained. . . . Constant incubation appears to have begun on the first day of April after which she was frightened out on two evenings. . . . Eggs No. 1 and No. 2 were found to have hatched on April 27; No. 3 hatched the following night, and No. 4 about five o'clock in the afternoon of April 29, showing that the period of incubation was about twenty-six days.
Following are some of Miss Sherman's observations on the young:
This owl may have been called the Shivering Owl, because it shivers. It certainly shivers, that it screeches may be a question for dispute. This peculiarity is one of the early things to be observed in the life of these nestlings; but the shivering does not become very pronounced until the bird is two days old, and continues until it is about two weeks old, at which time the young owl is well covered with thick down; therefore it seems quite possible that it shivers because it is cold. . . .
Until the shivering period was past they sought the warmth found under the mother's wings; after this, as one would naturally suspect, they, as do other young birds, continued to sleep much, standing in a bunch with their heads pressed together; they preened themselves but not so much as do some nestlings; frequently they yawned, monstrous, big-mouthed yawns. Stretching was the favorite exercise, during it the birds seemed to be made of india-rubber. On May 16 the height to which one stretched itself was seven inches by actual measurement. . . .
During their nest life but three varieties of cries were heard from them, the first, beginning as soon as they were out of the shell, had some resemblance to the peep of a chicken, and was uttered by them when out from under the mother's wings, seemingly a cry for shelter and for food; this ceased when they were about three weeks old. At this age a second cry was heard for the first time, which had a decidedly squeaking sound and was made when they were squabbling for the warmest place in the family circle. The remaining cry, a sort of chatter, appeared to be the tone for a dinner discussion, friendly enough in quality, for they were never seen to quarrel at meals. Besides these there was the snapping of the bill which commenced the day they began to show fear, and a hissing sound made when they were frightened. . . .
The male Screech Owl appears to have been the general purveyor for the family. In the fist fortnight of incubation there were nine mornings when an excess of food lay beside his mate; of this she rarely ate during the day, but there were times when she did so. On the remaining days of incubation she had food beside her twice, but as soon as the eggs commenced to hatch there was a super-abundance provided. An example of this was furnished on April 29 when there lay in store four meadow mice weighing about two-fifths of a pound altogether. This excessive provision lasted only a few days, the supply decreased daily, and none was seen after May 15. Nine o'clock, half past nine, and ten o'clock were hours upon which he was known to have brought food to the nest, eight o'clock in the evening being the earliest time. . . .
Bits of flesh clipped from meadow mice in store, that were placed in the mouth of a nestling, were swallowed with some difficulty and no apparent relish. Their beaks were stained upon the outside with bloody matter, and as they grew older they would nibble at the mother's bill as if teasing for food. All these things led to a belief that in their earlier days they were fed predigested or partially predigested food, which they pulled from the beak of the mother. . . . On the tenth an owlet was seen for the first time pulling at food (the body of a frog), as if eating it. The next morning during observations the mother lifted her head from the corner and appeared to eject something from her mouth; at once the owlets scrambled to the spot and seemed to eat for a few minutes. . . .
Pellets ejected by the young were found for the first time on May 10; it may be well to note that this was the first date upon which they were seen eating the food that lay in the nest. A pellet disgorged on May 27 weighed sixty-two grains, which was one-thirtieth of the weight of the bird that ejected it.
Dr. Arthur A. Allen (1924) made a series of careful observations on the method of feeding a brood of young screech owls, which he confined in a cage in front of a blind, equipped with a lantern, flashlight, and camera. He writes:
From the outset it was obvious that both parent birds were engaged in caring for the young. . . . They never both came together to feed but frequently when the flash light disturbed one bird before it had time to feed, the other would return with food and both would be near with food in their bills at the same time. The old birds were ordinarily silent in their hunting and feeding but the young birds, after they had been put in the cage, kept up a continuous humming during the night which lasted as long as they were hungry. If one of the young did not give the food call, the old birds paid no attention to him but fed the ones that called. The food was always brought in the bills of the old birds and placed directly into the mouths of the young. Large objects like birds or mice were often brought already partially torn or eaten or they were sometimes torn to pieces in front of the cage before being passed through the wire. Just as often, however, the entire bird was given to the young and they would fight among themselves for it. It was after one such tug-of-war that two of the young attacked the third and picked most of his bones by morning.
In order to determine the number of feedings, the amount of food, and its nature, George McNeill (Allen, 1924) remained in this blind nearly all night for seven successive nights, June 29 to July 6, inclusive. The earliest time at which feeding began was 8:25, and the latest was 9:12 p.m.; the earliest time at which feeding ceased was 2:50, and the latest was 4:15 a.m. The number of feedings was very variable, being 20, 73, 36, 14, 75, 67, and 72, respectively, on the seven nights. The most intensive feeding was on the night of July 4, when "the young Owls were first fed at 8:34 and between then and 1:40 were fed 75 times, two beetles and 73 moths. The birds then became quiet and as it was very chilly Mr. McNeill left. The next morning I gathered the feathers of six birds that had evidently been fed to the young after 1:40: Phoebe, Scarlet Tanager, Cedar Waxwing, Chipping Sparrow, Redstart, and Catbird."
From the above records it appears that from the time that the first egg is laid to the time that the young leave the nest about eight weeks have elapsed. Probably the young are watched over, and fed more or less, by their parents for five or six weeks more before they are turned away to shift for themselves.
As they tumbled about in their nest they very forcibly suggested human babies in fleecy white cloaks that are learning to creep. Held in the hand with their beaks downward and out of sight they looked like diminutive blind kittens; perhaps the most noticeable thing about them at that age was their large heads. But this winning aspect of the nestlings was of short duration. In a few days the pinfeathers began to show in the white down which soon turned to a dirty gray color. By the time they were twelve days old they had become most repulsive, exceedingly filthy to handle with an appearance that was decidedly repellent. Perfect miniatures were they of a doddering, half witted old man; the blue beak was prominent and suggested a large hooked nose, while the down below it took the shape of a full gray beard, and that on the top of the head looked like the gray hair that covers a low, imbecile forehead; the eyes not fully open were bluish in color, and had a bleared and half-blind appearance. This loathsome semblance lasted no longer than ten days by which time the eyes were full and bright and yellow, the bird was covered with a thick gray down, and looked as if a facsimile of it could very easily be made from a bunch of gray wool devoid of any anatomy.
The above somewhat fanciful but graphic description gives a very good impression of what the young screech owl looks like in its early days. The last stage referred to is what I call the downy juvenal plumage. This secondary down, or, more properly, downy plumage, is acquired before the young bird is half grown and before the flight feathers have burst their sheaths. It replaces the first, or natal down, the old adhering as white tips on the new. On the upper parts this downy plumage is basally pale "tawny-olive," or "Saccardo's umber," with grayish white tips, and barred with "sepia"; on the under parts it is grayish white and more narrowly barred with paler sepia. During this stage the two color phases begin to be distinguishable, the gray phase being grayish white and gray and the red phase more generally tinged with "pinkish cinnamon"; this difference becomes more pronounced as the flight feathers begin to develop. When the bird is about half grown the first winter plumage begins to show, first in the scapulars, then in the wings, and then in the tail; the bird is fully grown and the wings and tail are fully developed before there is much change in the body plumage; the molt of the body plumage occurs in July and August, beginning on the back, followed by the under parts, and lastly including the head.
This molt produces the first winter plumage, which is much like that of the adult, and is worn through the following spring and until the next summer molt, the first postnuptial. Young birds can be recognized in this plumage by the juvenal wings, tail, and scapulars; the wings lack the white on the outer webs of the primaries, which are broadly barred with "cinnamon" and dusky; and the broad white tips of the greater and median wing coverts and the white outer webs of the scapulars, so prominent in adults, are less pronounced in young birds; red adults have the central pair of rectrices nearly or quite clear red, and gray adults have them mottled; young birds of both phases have the central feathers more or less distinctly barred, and the lateral feathers more heavily barred and dusky. Adults apparently have one complete annual molt late in summer and in fall.
The screech owl gives us one of the best examples of dichromatism, apparently entirely independent of sex, age, or season, but shown to its perfection only in the eastern races; some of the western races show an occasional brownish phase; and an intermediate, brownish phase occurs rarely in the eastern races. Many years ago E. M. Hasbrouck (1893) made an extensive study of this subject, and published a paper based on the data obtained from 3,600 birds. He attempts to--
show, first, that while the red, the gray, and the intermediate phases are at present but individual variations of the same species--the gray was the ancestral stock; second, that the gray bird evolved the red, which at some future time will be a recognized sub-species with a range peculiar to itself, and thus dichromatism is one step in the evolution of the Screech Owl, while the various phases exhibited are the transitorial stages of development of one species from another; third, that this condition of affairs is influenced by four powerful factors (two of which, temperature and humidity, are dominant powers in geographic distribution), the most potent of which is temperature; fourth, that the predominating distribution of the respective colors is largely confined to the faunal divisions of the Eastern United States, and as such is approaching the sub-specific differentiation of the two phases.
His five maps illustrate the ranges of the eastern races, the areas occupied by each one of the phases exclusively and those in which one of the phases predominates, and the distribution of the phases in comparison with temperature, humidity, and forest growths; the distribution of the phases seems to correlate fairly well with the distribution of these factors. He makes the statement that whereas the offspring of parents of two different phases, or of two red parents, may be all red, all gray, or of both colors, "not a single record can be found of the offspring of a pair of gray birds showing the slightest trace of red." This statement seems remarkable, but I have no evidence to the contrary.
Food.--The screech owl enjoys a varied bill of fare including almost every class of animal life. Dr. A. K. Fisher (1893b) summarizes its food as follows: "Of 255 stomachs examined, 1 contained poultry [pigeon]; 38, other birds; 91, mice; 11, other mammals; 2, lizards; 4, batrachians; 1, fish; 100, insects; 5, spiders; 9, crawfish; 7, miscellaneous; 2, scorpions; 2, earthworms; and 43 were empty." He says of their hunting methods: "At night-fall they begin their rounds, inspecting the vicinity of farm-houses, barns, and corncribs, making trips through the orchard and nurseries, gliding silently across the meadows or encircling the stacks of grain in search of mice and insects. Thousands upon thousands of mice of different kinds thus fall victims to their industry."
Dr. Paul L. Errington (1932c) says: "My Wisconsin record for Screech Owl vertebrate and large invertebrate prey totals up to 137 individuals, in the following proportions: Norway rat, 1; meadow mouse, 49; deer mouse, 37; shrew (Blarina, 6; Sorex, 1), 7; small bird (predominantly English Sparrow according to feather evidence of kills), 36; fish, 4; crayfish, 3."
Dr. Allen (1924) says: "To summarize: remains of birds were found on 35 days, insects on 28 days, crawfish on 24 days, amphibians on 15 days, mammals on 12 days, fish on 6 days, and spiders, snails, and reptiles on one day each." He gives a list of the species of birds fed to the young, making a total of 24 species and at least 98 individuals, and says: "Since the feathers in the nest undoubtedly represent many more than one bird of each species, the grand total of birds required to feed the three young Owls from the time of hatching until left by the old birds was certainly over a hundred."
The long list of items in the food of the screech owl includes the following mammals: mainly mice of various species, but also shrews, rats, moles, flying squirrels, chipmunks, and an occasional bat. Illustrating the usefulness of the screech owl as a mouser, Forbush (1927) writes: "All one season I watched a pair that were rearing a brood near my cottage. . . . All the pellets and other refuse from their food that season showed only remains of mice, shrews, and insects. . . . While the owls were there, the mice did no damage to our young orchard, but two years later their box fell down and was not replaced for the next two years. The second winter the mice girdled nearly all of our apple trees. The next year a number of boxes were erected. The owls returned and we had no trouble from mice thereafter."
Although birds do not form so large a proportion of the food as mammals, the list of species is a long one, as follows: domestic pigeons, quail, ruffed grouse, woodcock, sparrow hawk, screech owl, downy woodpecker, kingbird, phoebe, wood pewee, horned lark, blue jay, starling, blackbirds, Baltimore oriole, goldfinch, junco, canary, indigo bunting, English and various other sparrows, cedar waxwing, swallows, scarlet tanager, vireos, water thrush and various other warblers, house wren, chickadee, nuthatches, brown creeper, catbird, bluebird, and various thrushes.
A farmer once brought to me a screech owl that had been living in his pigeon cote, and had killed nine of his pigeons; and there are several other similar records. I had one in captivity that broke into a cage and devoured a captive sparrow hawk; I could find only its feathers. Many young birds are taken from the nests of various small birds and fed to the young owls. Dr. Fisher (1893b) records a report of a screech owl, much emaciated and driven by hunger, attacking a large hen and attempting to carry it off. An instance of a screech owl killing a ruffed grouse is recorded by Dr. George M. Sutton (1927) as follows:
At about midnight on December 20, 1924, Mr. George Ryder, of LeRoy, Bradford County, Pennsylvania, captured a Screech Owl in a steel trap which he had set earlier in the evening on the body of a grouse which he had just found freshly killed, and from which he had frightened what he recognized as a small owl of some kind. Examination of the snow about the body of the grouse showed that no quadruped had caught the bird. Furthermore, the Screech Owl's stomach, which was examined at the writer's office, contained much of the head and neck of the grouse, as well as several sumac seeds, portions of rose-hips, and tiny twigs with buds attached, which must have been swallowed with the gizzard of the grouse. The owl was caught by both feet only a few minutes after the setting of the trap, so it is fair to assume that the eating had been done prior to the setting of the trap, probably just after the owl had killed its prey.
H. E. Tuttle (1920) says: "I came upon a Screech Owl one day, carrying what seemed to be a small kitten. I followed his line of flight, and as the burden proved too great a handicap for him in his effort to place a safe distance between us, he dropped it, but lingered near as if reluctant to yield it to my inspection. To my astonishment I discovered that it was an infant Owl, quite downy and quite dead."
Mrs. P. N. Jackson and G. Carleton (1931) write: "About two weeks ago, in Mendham, N. J., a Screech Owl came down the chimney of a house and ate up the Canary. . . . Feathers showed that the Canary had been pulled between the bars of the cage."
Screech owls feed quite extensively on insects; the list includes June beetles and other beetles, cutworms, grasshoppers, locusts, crickets, cicadas, katydids, noctuid moths, caterpillars, and hellgrammites. Many of these are caught on the wing. Dr. Sutton (1929b) watched a screech owl thus engaged, and writes:
At first we were somewhat mystified by her actions. Soon we made out, however, that she was capturing insects which were flying about the peripheral twigs of the tree. Some of these she evidently snatched from the twigs or leaves with her feet; others she caught in mid-air, with her beak. Since I had never known Screech Owls to capture prey thus I changed my position so as to be able to see the bird more clearly. From my new station under the elm tree I saw the bird catch thus, Flycatcher-wise, at least twenty insects, most, if not all of them, the large beetles locally called June bugs or May beetles. We watched her for at least three quarters of an hour. She caught about two insects a minute, returning promptly to feed the noisy young. . . .
This habit of capturing insects with the mouth, on the wing, instantly called to mind the characteristics common to the Orders Strigiformes and Caprimulgiformes. Birds of both Orders have soft, lax plumage permitting noiseless flight; both are at least to a degree, nocturnal, possessing relatively large eyes. The mouth of the Screech Owl, while hardly to be compared with that of the Whip-poor-will from the standpoint of size, is, nevertheless, relatively large or wide, and the hair-like feathers of the nasal portion of the facial disc probably perform the same insect catching function as the enormously developed rictal bristles of the Whip-poor-will.
Louis B. Kalter writes to me: "A Screech owl practically snatched from my hands two male cecropia moths (Samia cecropia), around 4:30 a.m., when I was attempting to catch the moths with my hands. In the evening I had hung a live female cecropia moth, by means of a thread, in the open window of my bedroom. It had lured a number of males by its scent and, when I leaned from the window to catch them, a screech owl swooped down twice and caught them; once it came within 3 or 4 feet of my hands."
Mr. Forbush (1927) says: "Professor Aughey dissected 8 of these owls in Nebraska during locust invasions and in their stomachs found 210 locusts, 2757 other insects, 2 mice and 1 small bird. The one that had eaten the bird contained also 32 locusts and 8 other insects."
In addition to mammals, birds, and insects, the screech owl has been known to eat snakes, lizards, frogs, toads, various fishes, crayfishes, snails, salamanders, spiders, scorpions, millipedes, and earthworms. M. A. Frazar (1877) found in a screech owl's roosting hole sixteen horned pouts, four of which were alive; all the ponds in the vicinity were under 2 feet of snow and ice, but in one pond, fully a mile away, a hole had been cut in the ice by fishermen, where he inferred that the owl had caught the fish; this involved a total flight of 32 miles for the 16 fish.
With such an extensive and varied bill of fare, it is difficult to arrive at any general conclusion as to the economic status of this owl. It depends largely on its environment and the most readily available food supply, for this owl evidently is satisfied with what animal food it can most easily obtain. Where mice, rats, and other small mammals are abundant, it apparently prefers them; in destroying them and in eating so many locusts, cutworms, and other noxious insects, it is decidedly beneficial. There are several cases on record, to its credit, where it has been useful in keeping in check, or driving away, an overabundance of English sparrows, which had become a nuisance in barns, hangars, and vine-clad houses.
But in a bird sanctuary a screech owl is an unwelcome guest. Miss Sherman (1911) found that her screech owls killed a great many small birds, especially juncos and song sparrows; all the latter disappeared in time; her verdict on the owls was that "their ravages were so great that it was decided if we desired a little bird paradise where all good birds were welcome through the summer time there Screech Owls could not be encouraged to remain"
Dr. Allen (1924) draws the following conclusions from his studies:
A census of the birds nesting in the sanctuary in 1923 showed a slight increase in the total number rather than a decrease, though all species exterminated in 1922 failed to reappear in 1923. . . .
There can be little doubt that the number of insects and small mammals destroyed by this pair of Owls could never compensate for the destruction of one tenth of the insectivorous birds eaten by the young. Though the Owls might spend the rest of the year feeding entirely upon insects and meadow mice, they could not possibly consume the equivalent of what would have been eaten by the 98 birds destroyed during the short space of eight weeks.
From the data here presented it seems evident that the Screech Owl is a powerful factor in maintaining the balance of nature but, from the standpoint of increasing insectivorous birds, he is an equally powerful menace.
Dr. John B. May tells me that he had some young screech owls confined in a latticed shed. "Through the openings of the lattice nasturtium plants climbed, and I found that the owls ate considerable of the stems and leaves of these vines. Pellets composed of the woody fibers of the leaf stems were frequently found in the shed." Perhaps they needed additional "roughage" in their food.
Behavior.--If the great horned owl can rightly be called a "feathered tiger," the screech owl deserves to be called a "feathered wildcat," for it certainly is a savage little brute, as some of the foregoing remarks on food indicate. Its courage in attacking birds much larger that itself is admirable, but cruelty and cannibalism are not so much admired. I once took a mated pair of these owls from a nest in which they were sitting on five eggs. The eggs went to a friend's collection, but I put the two owls in a cage by themselves in my aviary. I was surprised a few days later to find that one of them had killed and partially eaten its mate; I wondered if the loss of the eggs had anything to do with it. Fred. H. Carpenter (1883) says that his captive screech owl savagely attacked a long-eared owl which he put into the enclosure with it, so that it was necessary to separate the two birds. William Brewster (1907) published a thrilling story, on the authority of Mrs. John W. Ames, of Cambridge, of a pair of very aggressive screech owls that were raising a brood of young near a house in Concord, Mass. The occupants of the house were savagely attacked whenever they ventured near the trees where the owls were living after dark; even the neighbors were attacked when they passed the gate. People were repeatedly struck on the head and face, sometimes blood drawn, and this happened so often that they adopted the habit of wearing hoods or baseball masks when they went out in the evening. This was a rather extreme case of persistent hostility and boldness, but I have found in the literature no less than six somewhat similar accounts of screech owls attacking men, women, and children, in fancied defense of their young. This is apparently a common habit, but it oftener results in threats rather than actual injury to human beings.
The screech owl is one of our most strictly nocturnal owls. It does not hunt, and is said not to eat, during daylight. Soon after dusk it sallies forth on its large, silent wings and glides swiftly along over the lowland fields and meadows in search of mice, or courses over the treetops to catch the larger flying insects. During the day it is inactive, dozing in some hollow tree, some dark corner, or huddled up close to the trunk of some densely foilaged tree; often, however, it will perch motionless all day in some opener situation, relying on its concealing pose and protective coloration to escape detection. Often it will sit for hours at the entrance to a hole in a tree, or some opening in a building, facing the bright sunlight. Its eyesight is strong enough, with the pupil fully dilated, to see well at night, but, with the pupil contracted, it can also see perfectly in the brightest daylight, though it seems confused when suddenly brought from darkness to sunlight. The only one I ever induced to leave its nest voluntarily in daylight flew perfectly and swiftly off through the woods for a long distance.
Captive owls that I have tethered in the open could see clearly every bird that flew across the sky and would follow them with the eyes until out of sight.
As with all owls, the screech owl's hearing is very acute and of great assistance to it in its midnight hunting. The rustling of a mouse in the dry leaves or grass, the stirring of a bird on its roost, the buzz or soft flutter of an insect's wings, or the splash of a fish in a dark pool, all serve to guide it to its prey. Likewise its keen ears often warn it of an approaching enemy. Probably its ears are fully as useful as its eyes at night.
Screech owls are ordinarily quiet, gentle birds; they can be lifted from their nests or roosting holes without offering any resistance; they may indulge in ominous bill snapping but seldom use their claws, which are sharp as needles. They make very good pets provided they do not come in contact with other species, or even other individuals of their own species, which may result in tragedies; they love to be stroked or have their heads scratched; they are very cleanly, drink water freely, and are fond of bathing. Wild owls have been known to bathe in bird baths, often exhausting the supply.
Dr. Fisher (1893b) says: "Once about dusk the writer came upon a small family which had emerged the moment before from the water. They were sitting on some low alders over a shallow portion of the stream, ruffling up and shaking the water from their feathers, and presented a soaked and forlorn appearance. Apparently they were too wet to be able to fly well, for when approached they fluttered off heavily into the thicket and soon escaped from sight in the growing darkness. The number of times this Owl has been drowned in water barrels indicates its fondness for bathing."
W. I. Lyon (1922) had an interesting experience with one of these owls that was nesting in the same tree with a pair of flickers; the owl's eggs were destroyed, and for five consecutive days thereafter the owl was found in the flicker's nest, brooding the young flickers; the latter were regularly fed by their parents and were always uninjured; the owl had even brought in a small bird to feed to the young.
The screech owl is well aware of the concealing value of its well-known hiding pose; it will maintain this pose, even though closely approached, and remain immovable until it realizes that it is discovered; then a decided change takes place. The following extract from Owen Durfee's notes gives a very good idea of the whole performance: "I had the pleasure of finding two screech owls sitting side by side on a horizontal limb. The attitude was long drawn out, the whole body being stretched to its limit, the wings and feathers held as close to the body as possible. This gave them the appearance of two long stubs, the top of the head being nearly square across. The eyes were slanted slits, and while the head was directly toward me, the body was swung sideways so as to keep the wing in front as a shield; in other words, they were looking over their shoulders. In fact, one of them, as I walked part way around them, suddenly swung halfway around, so that it was looking at me over the other shoulder. After a few moments one of them evidently realized that it was discovered and underwent a sudden transformation; from a vertical position it quickly assumed a horizontal one, of only about one-half as great a height. It thus assumed a squatting position across the branch, the feathers being fluffed out, the head a round ball, the round eyes wide open, and with one click of the bill, it flew heavily away. A few moments later, the other bird followed in exactly the same line of performances."
Louis O. Shelley writes to me: "As we were walking up a hill road we spied a screech owl, in gray phase, perched on a short limb tight up against the bare trunk of an ash tree. As we came into sight, very slowly the bird attained the protective pose of a dead stub. We approached to within 12 feet, waved our arms, called and even tossed pebbles. But the bird was fain to move as it sat, eyes half closed, in the warm sun. We each had an orange and were debating tossing them up at the bird. But the instant we drew them forth and the sun struck them, emphasizing their golden color, the bird quickly resumed its normal attitude, edged along the limb and, spreading its wings, noiselessly swept away."
Voice.--The name of this owl is somewhat unfortunate, as it very seldom indulges in anything that can rightly be called a screech. Mr. Forbush (1927) heard such a note from only one individual, of which he says: "It resembled the note of the siren whistle, beginning low and full and gradually rising without the usual tremolo until it ended in a shrill shriek."
Frances H. Allen has given me his description of two of the notes: (1) "the well-known wail, or whinny, the so-called love song, consisting of a succession of short, even, low notes delivered with varying degrees of rapidity. It also varies in pitch. Sometimes the first part is slow and the latter part rapid, virtually a trill"; (2) "wheeoo, a mellow whistle with a falling inflection, often followed by three shorter notes, each a very little higher in pitch than the preceding note--wheeoo, woo, woo, woo."
I am tempted to quote Thoreau's (Langille, 1884) graphic description of the love song; he says: "It is no honest and blunt tu-whit, tu-who of the poets, but, without jesting, a most solemn, graveyard ditty, the mutual consolations of suicide lovers remembering the pangs and the delights of supernal love in the infernal groves. . . . Oh-o-o-o-o that I had never been bor-r-r-r-r-n sighs one on this side of the pond, and circles with the restlessness of despair to some new perch on the gray oaks. Then--that I had never been bor-r-r-r-n echoes another on the further side with tremulous sincerity, and bor-r-r-r-n comes faintly from far in Lincoln woods."
The screech owl's call is seldom heard until after dark, but Mr. Kalter tells me that he has heard it calling on at least three occasions in bright daylight, at 11:30 a.m. and 1:15 and 2 p.m. On two occasions he has heard one calling while in flight, once while being chased by a robin. Dr. Winsor M. Tyler contributes the following good description of the screech owl's notes:
"The commonest note of the screech owl is a whistle, well within human range, which, rising a little in pitch, becomes tremulous, then slides down below the starting point, the tremulous quality becoming so marked that, near the end, the voice is almost divided into separate notes. The whole has a sad, dreary effect, due rather to the tone of voice and the sliding change of pitch than to any minor intervals.
"The owl varies this cry in several ways. The note may begin on various pitches--that is, one wail may be markedly higher or lower than the wail preceding it; the pitch may rise very little, or it may rise two or more tones before it falls at the end; the pitch may fall a varying degree, sometimes three or four tones; and a fourth variation is at the beginning of the cry when the quavering quality is delayed appreciably.
"A second note, less common than the wail in proportion of about 1 to 10, may be suggested by the letters ho-ho-ho-ho, pronounced with a good deal of aspirate quality. This series of notes is generally given alone, but it may sometimes immediately follow the wail. The pitch of this call is about five tones below the highest note of the wail, and as a rule does not vary, although it occasionally runs upward a little. It is sometimes heard in the daytime.
"I have often heard another note in August and early in September, when several owls--presumably a family out hunting--had gathered 'in the dead vast and middle of the night' and were calling to one another from the trees about Lexington Common. Among the subdued whinnyings and tremulous owlish coos, there comes out of the darkness a sharp cry--almost human, or like a little child's voice--a cry like keerr, sometimes rolling at the end. It is about as long as a flicker's call note, and moves about as the bird flies from one perch to another. Sometimes the note is uttered with so much energy that it suggests excitement or eagerness.
"It seems probable that this is the call of a fledgling owl, signaling its whereabouts to its parents while they are away, searching for food among the branches of the trees, or on the grass underneath. On one occasion, when the owls were about the house, at 1 o'clock in the morning, I heard the shriek of a robin burst out of the night."
Field marks.--A small owl, with yellow eyes and prominent ear-tufts, is quite likely to be a screech owl, as the long-eared owl is considerably larger and slenderer. It is very seldom seen on the wing in the daytime, unless driven from cover. The bright reddish-brown color of the upper parts in the red phase is quite distinctive; no other North American owl has any color approaching this. In the gray phase it is much grayer than the long-eared, and very much shorter and stouter. In the gray phase the color pattern resembles the rough bark of an old tree, and the hiding pose, described above, increases the resemblance in the attitude in which the bird is oftenest seen in the daytime.
Enemies.--The larger owls and occasionally some of the larger hawks have been known to kill the screech owl; prowling cats or other predatory animals may pounce on one while it is securing its prey on the ground. Its less dangerous, but far more annoying, enemies are the crows, blue jays, and other small birds, which never lose an opportunity to pester, scold, and annoy one of these little owls when they can find it sleeping peacefully. The location of an owl can often be detected by the presence of a noisy mob of small birds, flitting about, chirping, and shrieking at the enemy they rightly fear and detest, but seldom daring to venture too near. The owl may stand this abuse with stolid indifference for some time but may be driven eventually to seek seclusion in some dark hollow. I once followed up a noisy mob of blue jays in a dense thicket and shot one of them, as I wanted a specimen; when I picked it up, I was surprised to find a dead screech owl lying near it, which I had killed unexpectedly. Many screech owls have been found dead along the much-traveled highways, apparently killed by automobiles.
Winter.--Screech owls are supposed
to be permanent residents throughout their range, but probably
some migration takes place from the northern portion of their
summer range. They certainly wander about more in search of food
in winter, as they are often seen at that season in places where
they are not found in summer. The scarcity of food in the northern
woods when the ground is covered with deep snow drives them to
more fruitful hunting grounds about farms and even into towns and
cities, where they find plenty of mice, rats, and English
sparrows, as well as dark and secluded nooks in which to find
shelter, about farmhouses, barns, corncribs, and outbuildings.
Many of these owls have been found in winter in a sadly emaciated
condition, which indicates that they have been driven by hunger
from some less hospitable region.
Eastern Screech-Owl* Otus asio
*Original Source: Bent, Arthur Cleveland. 1938. Smithsonian Institution United States National Museum Bulletin 170 (Part 2): 243-258. United States Government Printing Office