Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.
Bent Life History for the American Crow - the common name and sub-species reflect the nomenclature in use at the time the description was written.
It has been aptly stated that if a person knows only three birds one of them will be the crow. The crow, if we include all the five subspecies, is widely distributed over the greater part of the North American Continent. Throughout this area this familiar bird is instantly recognized by anyone who sees it. Because of its striking coal-black plumage, its large size, its unusual adaptability, its extreme cunning and apparent intelligence, its harsh garrulous notes, and its habit of frequently appearing in the open, it has become one of the best known of our American birds. The common name crow is universally applied, and I know of no English local synonyms for it. Even before white man came to America it was well known to the Indians and every tribe had its name for this bird, which was such a conspicuous creature of their environment.
Unfortunately the crow has a questionable record as far as his relations to human interests are concerned. No bird has been the subject of more heated controversy than the crow, and none of our birds have been more violently persecuted by man. In spite of incessant persecution the crow has been able to outwit his human adversaries by its unusual intelligence and instinct of self-preservation, to the extent that it has been able to maintain its existence in all parts of its wide and diversified range. For this the crow commands our admiration.
Spring: A few crows winter in northern New England, but the majority of them are found farther south during the season of extreme cold weather. The first arrivals of the spring migration reach Maine during February, but it is not until the latter part of the month or the first week of March that they become common. Low (1934), in connection with banding operations at the Austin Ornithological Research Station on Cape Cod, Mass., has collected data that suggest that three populations of crows may be found there as follows: permanent residents, breeding birds that winter to the south, and northern breeders that either winter or migrate through the region.
Determinations of sex ratios at roosts by Hicks and Dambach (1935) indicate that the migration of the sexes may differ in range and extent. Certain of our populations of crows undergo a relatively short migration, but banding operations conducted in Oklahoma by Kaimbach and Aldous (1940) prove that many of the crows wintering in that State migrate to the Prairie Provinces of Alberta, Saskatchewan, and Manitoba, a flight of more than a thousand miles. One crow shot at Meadow Lake, Saskatchewan, at latitude 540 N. had traveled 1,480 miles and another at Camrose, Alberta, 1,435 miles from their ~vinter home in Oklahoma. Out of 714 crows banded, 143 recoveries were obtained. Of 65 crows recovered during the nesting season, 49 were from the Prairie Provinces. It is obvious that many of the returns recorded in the States north of Oklahoma were on their way to or from the Canadian breeding grounds. The results obtained by Kalmbach and Aldous not only give us definite information concerning the extent of crow migration but are important in their relation to the value of the extensive control measures undertaken in Oklahoma.
Crows have been used for important experimental work concerned with different phases of migration. William Rowan, proceeding on the hypothesis that the migrating stimulus is a physiological one originating in the gonads or sexual organs, experimented on various birds, but chiefly the crow. The crows were confined in outdoor aviaries at Edmonton, Alberta, and exposed to temperatures as low as 440 F. below zero, but from the first of November until early January they were subjected to an ever-increasing amount of light, supplied by electric bulbs. In this way they were artificially subjected to light conditions that approximated those of spring. At the close of this period it was found that the gonads had actually attained the maximum development normally associated with the spring season. Control crows not subj ected to the light treatment showed no development of the gonads. The birds, both the light-treated individuals and the controls, were marked, banded, and then liberated. By means of radio and other publicity, the cooperation of hunters was solicited for the return of the bands. While bands from eight of the experimental crows were returned from the north and northwest (two of them from a point 100 miles northwest of the point of liberation), an equal number were recovered from the south and southeast, thus to some extent nullifying the experiment. This work does indicate that the stimulus that initiates migration is a physiological one, and it is assumed to be a hormone produced by the interstitial tissue of the reproductive organs.
Courtship: Edward J. Reimann in correspondence writes of the early courtship of crows he observed, in the vicinity of Philadelphia, Pa. On March 8, 1940, he saw crows paired at most of the nesting localities along the Pennypack Creek. In some of these places two or three birds and at times four or five, what he supposed to be males, were seen chasing a female in courtship. Late in March the crows were rather noisy as he passed through each prospective territory. At some places courting was still going on where small groups of crows milled about the trees. Males chased the females, courting them while performing aerial gyrations of diving and wheeling. It was apparent to Reimann that the birds were pairing off, were claiming their nesting territory, and were about to drive their unwanted rivals from the scene.
Charles W. Townsend gave the subject of courtship of many birds serious and careful study, and no one is better qualified than he in the recording and interpretations of their performances. The following account is based on his observations of crows at Ipswich, Mass. His published account (1923) in part is as follows:
Courtship in birds is expressed in three ways, namely in display, dance and song. * * * The courtship song of the Crow consists of a rattle, a quick succession of sharp notes which have been likened to the gritting of teeth. That this is a courtship song and not merely one of the bizarre expressions of this versatile bird, is shown conclusively by its association with courtship display and dance. Like all bird songs it is commonest in the spring, but may occasionally, as in the case with many bird songs, be heard at other times, especially in the fall of the year, when it is explained by the "autumnal recrudescence of the amatory instinct." Although the song is generally given from a perch, it may also he given on the wing, constituting a flight song, although there is no other difference in the character of the two songs.
The whole courtship of the Crow varies somewhat, but the following description of this act, seen under favorable circumstances, is fairly typical. A Crow, presumably the male, perched on a limb of an oak tree, walked towards another and smaller Crow, presumably the female, that seemed to regard him with indifference. Facing the smaller one, the male bowed low, slightly spreading his wings and tail and puffing out his body feathers. After two bows, he sang his rattling song, beginning with his head up and finishing it with his head lower than his feet. The whole performance was repeated several times. The song, such as it was, issued forth during the lowering of the head. * * *
During the love season, fights by rival Crows are common. Each bird tries to rise above the other in the air, and, with noisy outcry, each attacks the rival. Sometimes their struggles are so violent that the birds come to the ground, where they continue their fight and sometimes roll over together in their efforts, all the time voicing their wrath.
On the other hand, one may sometimes chance upon the loving actions of affianced couples. More than once I have seen one of a pair that were sitting close together in a tree, caress the other with its beak and pick gently at its head. The mate would put up her head to be caressed, and I have been reminded of billing doves.
Later Townsend (1927) made further observations which he elaborated upon as follows:
Spending the nights in an open lean-to in my "forest," at Ipawich, I found myself listening every morning to the courtship song of the Crow close at hand, and, on May 3, 1926, I discovered from my bed that a pa~r had their nest in a white spruce twenty-five yards from me, so that I was able, to watch them closely. At about four-thirty every morning I awoke to the rattling song of the Crow, and I often saw one flying about in irregular circles, singing and chasing another. Both alighted on trees, especially on a spruce, from time to time. The song was given in the air and from a perch, and once I heard it given as a whisper song. I also heard for the first time at the end of the rattle a pleasing sound which suggested the cooing of a Pigeon or the note of a cuckoo dock, but softer and more liquid. It was usually double: I wrote it down coi-ou or a single cou: and generally repeated several times, although sometimes given only once. These soft sounds, which I heard many times when the bird was near, generally followed the rattle, but were often given independently. When the bird was perched, he bowed and puffed out his feathers at the time of their delivery as during the rattling song. The cooing was also given in the air and on one occasion, I saw a bird drop slowly down with wings tilted up at an angle of forty-five degrees, singing as he fell. The rattle song was once given fifty-four times in succession, followed by a series of cous. The female was at times very importunate, calling slowly car car like a young bird begging for food. If the male approached, the calling would become more and more rapid and end exactly as in the case of a young bird in a gurgle or gargle: car, car, co#, ccwkle, cowk!e, cowkle. After mating the male .would fly to the next tree and call loudly cow-cow several times. Occasionally the loud wa-ha-ha-ha was given. An examination of the nest made at this time showed three heavily incubated eggs.
Nesting: In northern New England and the Maritime Provinces the vast majority of the crows nest in coniferous trees and those that I have examined have ranged 18 to 60 feet from the ground. Of 22 nests observed in Maine, 12 were in pines, 6 in spruces, 3 in firs, and only 1 in a hardwood tree, an oak. A nest containing six eggs found on May 20, 1936, near Brunswick, Maine, is typical. It was in a large pine located near the center of a 10-acre grove. The nest was built close to the trunk of the tree and was supported by three good-sized horizontal branches at a point 42 feet from the ground and approximately 30 feet from the top of the tree. The foundation of the nest was made up of branches and twigs of oak, beech, and pine, the largest ones were onefourth to three-eighths of an inch in diameter and 10 to 16 inches in length. The nesting bowl was made up of smaller twigs interwoven with strands of bark. The soft compact lining was entirely of finely separated fibrils of bark, which apparently were shredded by the birds before being placed in position. The foundation of nesting materials measured 22 by 26 inches, the depth of the nest from the upper rim to the base was 9 inches, and the rim of the nest proper was 12 inches in diameter. The interior of the nesting cup occupied by the bird was 6 by 7 inches and its depth ~ inches.
All the nests of the crow are substantial and well built; they are crude in general external appearance but always delicately and warmly lined. The main departure from the type described above is the nature of the materials used in lining the nesting bowl, a difference somewhat dependent on their availability. Different nests may he lined with moss, reed fibers, grass, feathers, twine, rags, wool, fur, hair, roots, seaweed, leaves, and similar materials.
The crow seems to prefer coniferous trees not only in the northern sections of its range but even in the south where such trees abound. In States where hardwood trees predominate, they are more frequently selected as nesting sites. T. E. McMullen, who has made extensive observations on the nesting sites of 227 crows in Pennsylvania, Delaware, and New Jersey, reports finding 112 nests in oak trees, 62 in other species of hardwood including 13 in maple, and 11 in beech trees. The remaining 43 were in coniferous trees, 24 in pine, 17 in cedars, and 2 in hemlocks. The above nests varied from 10 to 70 feet in height from the ground, but the majority exceeded 25 feet. Edmund J. Reimann writes that he has found nests in Pennsylvania that were built at a height of 100 feet from the ground.
In the agricultural areas of the Middle West, where there is a lack of large trees, crows resort to second-growth timber and shrubs of various kinds. In central Illinois favorite nesting sites are the Osage-orange fences. These hedges, abundantly armed with thorns, offer excellent protection, even against the prowling naturalist who may wish to examine the nests.
The crow is adaptable in the choice of its nesting site. In the western Canadian provinces there are numerous instances where the crow has nested on the ground either from choice or because of the lack of trees. Ferry (1910) found a crow's nest at Quill Lake, Saskatchewan, that was situated on the ground at the forks of the dead branches of a fallen and nearly burned up weather-bleached poplar tree. At Regina, Saskatchewan, Mitchell (1915) found a crow's nest on the ground between wild-rose bushes; others were placed on clusters of rose and low bushes just a few inches above the ground. On June 13, 1935, Aldous (1937) found two crow's nests built on the ground along the shore of Lake Manitoba. Another nest containing three eggs was found in the tules over the water, and a fourth nest was built on marshy ground among the reeds. In the latter two cases there were trees and brush in the vicinity, and apparently these situations were a matter of choice on the part of the birds.
Horning (1923) cites an unusual experience with a nest that he found at Luscar, Alberta. "We found a crow's nest in a willow thicket about ten feet from the ground, on May 28, 1922. The situation surprised us, as the Crow usually builds very high. and there were high trees within a few hundred yards. We thought that the presence of an abundant food supply, in the shape of a dead cow, within twenty-five yards may have been the reason for the choice of nesting site. We cut down the nest, which contained three eggs, newly laid, and photographed it, leaving it not more than two feet from the ground, and inclined at an angle of about 55 degrees. We removed the eggs. * * * Judge of our surprise, on re-visiting the nest on June 1 to find four new eggs. * * * It seemed to us very unusual for the Crows to re-occupy the nest especially when so close to the ground and at such an angle"
Occasionally crows select sites that are an extreme departure from the usual situations. Harold M. Holland in correspondence states that a pair nested in the hollow of an old stub located in a wooded tract in Knox County, Ill. They nested in this place for at least three seasons in preference to other numerous apparently suitable locations offered by the surrounding woods. Potter (1932) states that a pair of crows remodeled the top of a disused magpie habitation.
Bradshaw (1930) comments on unusual nesting sites he found in Saskatchewan as follows: "In many treeless sections of the prairie, such as Big Quill Lake, crows have been found nesting on the crossarms of telephone poles. In such cases one usually finds nearby a marsh well-stocked with ducks, coots, rails, grebes, and other marsh-loving birds. Probably the easy available food supply is the principal factor for the crow locating in such areas. * * *
"The most unique nesting site of the crow encountered was one found on the top of a chimney of a country church, between the towns of Pense and Lumsden." On the same road a pair of crows built their nest in a chimney of an abandoned house. In both cases, however, there were plenty of trees that the crows might have chosen for their nests.
Dr. S. S. Dickey, who has made extensive observations of crows in Pennsylvania during the nesting season, contributes the following observations made of the procedure of nest-building: "The female descended into the underwoods or would move along branches of the trees to masses of twigs. She would take one of them into her beak, twist it loose from its fastenings, and hurry with it to the site she had chosen for her nest. At first she tended to drop sticks en route, or else would proceed awkwardly in placing them in a fork or crotch. She dropped many sticks, causing a veritable heap of rubbish near the base of the nesting tree. Finally after many trials she managed to arrange a loose array of sticks in the base of the fork. Most of the work was done in the morning hours between 7 and 11 o'clock. Thereafter she appeared to weary and would fly away in company with the male in search of food. Late in the afternoon and shortly before dusk she proceeded again to work on her nest. The walls grew consecutively from coarse sticks and twigs to finer materials. She added mud, strands of rope, rags, corn husks, mats of dry grass, roots, moss and weed sterns, and strips of bark from various kinds of trees. The rim was nicely rounded off with strips of grapevine bark. The interior of the deep wide cup was tightly lined with inner bark fibers, pads of hair, fur, wool, and green moss. It required approximately 12 days to complete the nest after the first sticks had been placed.
"If bad weather conditions prevailed, several days would elapse before the first egg was deposited, although in one nest an egg had been laid in spite of the fact that the edge of the nest was encrusted in snow. During fair warm weather eggs were found in the nest a day or two after the nest had been completed"
Although not mentioned by Dr. Dickey, it has been noted by many observers that both male and female take an active part in the building of the nest as well as sharing in the incubation of the eggs.
Eggs: The number in a complete set of crow eggs is usually four to six, but in some cases there are only three and in others as many as eight or nine. Macoun (1909) reports an unusual set of ten eggs. In the latter instances it is probable the large number of eggs are the product of two birds, as it has been observed that two females in addition to the male have shared a single nest. Bendire (1895) has given us an excellent description of the eggs of the crow based on a wide experience and the study of large numbers of specimens. His account is as follows:
"Crows' eggs are rather handsome, and vary greatly in shape, size, color, and markings; the majority may he called ovate, but both short and rounded ovates, and elliptical and elongated ovates are also found in a good series. The ground-color varies from malachite and pale bluish green to olive green, and occasionally to an olive buff. The markings usually consist of irregularly shaped blotches and spots of different shades of browns and grays. In some specimens these are large, and irregularly distributed over the egg, usually predominating about the larger end, leaving the ground color clearly visible. In others again the markings are fine, profuse, and evenly distributed, giving the egg a uniform dark olive-green color throughout"
Bendire gives the average measurements of 292 eggs in the United States National Museum as 41.40 by 29.13 millimeters or about 1.63 by 1.15 inches. The largest egg of the series was 46.74 by 30.78 millimeters, or 1.84 by 1.21 inches; the smallest 36.07 by 25.91 millimeters, or 1.42 by 1.02 inches.
Sometimes eggs of abnormal size have been found. G. Ralph Meyer collected a set of eggs in which one egg measured 2.00 by 1.25 (50.8 by 31.8 millimeters), much larger than the largest egg in the large National Museum series. One or more eggs dwarfed in size have been found in sets in which the other eggs ai-e normal, but these usually prove to be sterile.
There are a number of reported cases of erythristic crow eggs, in which there is present an excessive amount of red pigment. In correspondence William Rowan, of Edmonton, Alberta, informs me that he has two sets of erythristic eggs that he obtained from central Alberta. They were laid by the same bird in successive years, and he states further that this same type of egg has been found in the same nest for seven successive years. Mr. Rowan believed that these eggs were unique and represented the first recorded case of erythrism in crow's eggs. However, there are published descriptions of so-called abnormal red-colored eggs that are undoubtedly cases of erythrism. Following are a few that have come to my attention. Bendire (1895) states as follows: In an abnormal set of five eggs, presented by Dr. A. K. Fisher to the United States National Museum collection, four have a pinkish buff ground color, and are minutely speckled with fine dots of ecru drab resembling somewhat in general appearance a heavily marked egg of the American Coot. *** In another specimen, presented by Dr. Louis B. Bishop, the ground color is salmon buff and this is blotched with pinkish vinaceous. The entire set of six eggs was similarly colored. Sage, Bishop, and Bliss (1913) mention six pinkish eggs of a set obtained near New Haven, Conn., on May 8, 1884. Jacobs (1935) describes a set of five eggs he found May 1, 1934, in a nest located in a willow tree near Waynesburg, Pa., as follows:
Throughout the whole set there is not the slightest suggestion of the usual greenish-drab shades. The shell, held to the light, appears a rich cream-white such as seen in the eggs of the Eastern Sparrow Hawk, and on the whole, resembles in coloration eggs of the latter collected on the same day. The smallest egg is less thickly marked and contain sparingly scattered hold patches of mauve and maroon purple, which tints are brought out by the brick-red laid over varying shades of lilac and lavender, the majority of them all on the smaller half of the shell. It is a beautifully spotted egg with brick-red, mauve and maroon purple about equally apportioned and equalling the amount of lilac and lavender shades which are untouched by the reddish pigment.
The ground color of the four eggs originally rich creamy-white with lavender blendings in paler underlays is heavily mottled over with brick-red giving the shells a uniform rich vinaceous appearance, over which are diffused blotches of strong vinaceous-cinnamon blending into the underlays. Thus we have, in these five crow eggs, specimens appearing like huge Cactus Wren eggs but the general red shade is really stronger than that of the wren's eggs.
Incubation: The incubation period of the crow is 18 days. One brood is reared each year, but in the southern part of the nesting range two broods each season are not unusual. Both male and female may take part in incubation and both share in the care of the young. Macoun (1909) reports a nest in which both birds were sitting on the eggs at the same time. The cavity of the nest was much larger than usual. There were five nearly incubated eggs in the same stage of development, indicating that these birds were male and female rather than two females. Occasionally three crows may be seen about the nest, but because of lack of sexual differences of plumage it is difficult to determine whether they represent cases of polygamy or polyandry. There is indirect evidence, however, that two females may be concerned. There are a number of cases on record where two sets of eggs were found in a nest that hatched on different dates. Jung (1930) found a crow's nest on June 15, 1928, in Alberta, Canada, that contained three eggs and one young about a week old. When the nest was visited the next day a fourth egg had been added. Three crows were seen about the nest and it is apparent that two of them were females, both of which were contributing eggs to this communal nest. In other cases three crows were concerned with a single nest, which contained a normal set of eggs hatching on the same date. Here, it is probable, two males were involved.
Young: The young when first hatched are pink or flesh color and scantily clad with tufts of grayish clove-brown on the head, back, and wings. At five days of age the eyes are open and the exposed parts of the skin have acquired a brownish-gray color. At 10 days the principal feather tracts are established by the rapidly growing feather papillae. At this stage they assert themselves by loud clamorings for food, and the presence of a nest may be revealed by their incessant calls, especially as they grow older. When the young crows reach the age of 20 days many of the contour feathers are unsheathed, presenting a dull black color. Tufts of down still cling to the tips of these juvenal feathers, especially in the region of the crown. The eyes are a dark blue-gray, the scales of tarsus and toes are grayish black, the upper mandible or maxilla is black, and the lower mandible is pale yellow or horn color streaked with gray. The lateral basal portions of the gape are yellowish orange. At this age tufts at the base of the bill are developed.
After four weeks most of the feathers are completely unsheathed. The young at this stage also show a marked change in behavior especially in regard to a human visitor. Before this time they were passive but now exhibit fear and offer resistance at being handled or lifted from the nest. At this time they may stand on the rim of the nest or even leave to nearby branches of the tree where they are fed by the adults. In the course of another week they are capable of leaving the nest and making their initial flight. If disturbed they may leave the nest before reaching the age of five weeks.
Plumages: The young in the completed juvenal plumage are dark grayish black above, with the underparts somewhat duller in tone; the wings and tail are black with violet and greenish reflections; iris bluish and the bill and feet grayish black.
The first winter plumage is acquired by a partial postjuvenal molt, which involves the body plumage and wing coverts but not the rest of the wings or the tail. The young in this plumage are similar to the adults, but the feathers show less gloss and the majority of the specimens have a greenish hue. The underparts are of a duller black, the belly with a dull slaty cast. The first nuptial plumage is acquired by wear, the feathers becoming brownish and worn by the end of the breeding season. The adult winter plumage is acquired by a complete postnuptial molt. The sexes are alike in plumages and molts. All parts, including bill, legs, feet, and claws, are deep black. The plumage of the body has a distinct metallic gloss of violet, and the wings are glossed with bluish violet and greenish blue; iris brown.
Albinism is common in the crow, judged from the more than 25 reported cases that have come to my attention. Since an albino crow offers such a striking contrast to the normal plumage, and because crows are more readily observed than the more secretive species, there are many reports of albinism. A few of the more interesting cases are cited below.
In the Bowdoin College collection there is a female crow collected at Yarmouth, Maine, that is pure white, including the bill, feet, and claws. The iris of this specimen was pink and so the bird was a pure albinistic type. Two albino crows taken from a nest near Portland, Maine, in 1910 were mounted by J. A. Lord, a taxidermist in Portland, An albino crow was seen at South China, Maine, for a period of several weeks during August 1930. F. A. Stuhr, of Portland, Oreg., reported having four live crows that were taken from a nest in Lane County, Oreg. Three of them are almost entirely white, showing only slight black colorations on the primaries and secondaries and at the base of the bill. The iris of these birds is brown, but the feet and tarsus are nearly white. Fleming and Lloyd (1920) report that two albino crows were taken from a nest 9 miles north of Toronto on June 29, 1908. Both birds were grayish white, the eyes blue-gray, the feet lead black, and the beak horn color. Harry Piers (1898) reported a partial albino collected near Halifax, Nova Scotia. His description is as follows: "Its general color was brown, darker on the throat, cheeks and belly; scapulars and feathers of back margined obscurely with whitish; primaries mostly whitish; tertials white; tail feathers light reddish brown margined with whitish on outer edge; legs, bill and iris brown." Several crows similar in coloration to the one described by Piers but with certain variations have been reported by other observers.
Warne (1926) cites a very unusual case of a pet crow that after five years suddenly acquired white feathers in each of its wings; when the wings were spread, about half of the area was white. Previous to this time they were black. Albinism is a hereditary character, and why white feathers would replace black feathers after five years is difficult to explain.
Longevity: We have relatively few records on the longevity of the crow. Banding of the birds has not been conducted in sufficient numbers or for a long enough time to yield definite results, but the following four banding returns are of interest: A crow banded as a nestling in Saskatchewan in July 1924 was shot five years later in July 1929 only a mile and a half from the place of banding; one banded at Garden Prairie, Ill., was shot five years later at Marengo, Ill., on March 25, 1934; one banded at Richmond, Ill., on May 28, 1927, was shot seven years later in Kenosha County, Wis., on March 13, 1934; and one banded at Lundar, Manitoba, on May 1, 1926, was shot seven years later in Grant County, S. Dak., on April 2, 1933.
Kaimbach and Aldous (1940) are of the opinion that relatively few crows in the plains area live more than four years. This supposition is based on the rapid decrease in the number of returns during the years following the release of the birds. Out of 143 returns of 714 crows banded, 76 were received the first year and 47, 12, and 8 (first six months) in the successive years. All were reported killed, which emphasizes the intense persecution the crow receives from the hands of the gunner. It is possible, state these authors, that the number of returns for the crows banded might have been greater were it not for the fact that, in their winter home, many are killed in bombings under conditions not conducive to the recovery of the bands.
Crows kept in captivity have lived spans of life exceeding 20 years, but it is doubtful if many individuals in nature ever approach that age.
Food: Few ornithological problems have been of greater widespread controversy than the economic status of the crow. It is an omnivorous feeder and readily adapts its food habits to the changing seasons and available food supply. Its food varies so greatly that isolated observations may be very misleading unless the food habits are considered from the standpoint of the entire population through all seasons of the year. If one is biased it is relatively easy to find abundant evidence ehher for or against the crow. It is no great wonder that this bird has been the subject of heated debate between the conflicting interests of those who wish to destroy and those who would protect this species with no thought of control. The advocates of either side of this question are probably sincere, but what we need is a common-sense solution of the problem, combining the interests of both factions. Only the thoughtless shortsighted person desires to have the crow completely exterminated, and the overzealous conservationist should submit to a reasonable control of a species when large numbers prove destructive to man's best interests.
The resourcefulness of the crow is vividly indicated by the fact that the Biological Survey identified 650 different items in the food eaten by 2,118 crows collected in 40 States and several Canadian provinces. According to Kalmbach (1939), "about 28 per cent of the yearly food of the adult crow is animal matter and consists of insects, spider, millipeds, crustaceans, snails, the remains of reptiles, amphibians, wild birds and their eggs, poultry and their eggs, small mammals and carrion. About two-thirds of the animal food consists of insects, chief among which are beetles and their larvae and Orthoptera (grasshoppers, locusts, and crickets), each group constituting more than 7 percent of. the food of the crow, and comprises the essential beneficial feature of the food habits of the species.
The numbers of insects eaten vary with the season. For example, few May beetles are eaten early in spring, but by April they constitute 5 percent of the food and in May, at the peak of abundance of May beetles, they comprise nearly 21 percent of the bird's diet. Likewise, the monthly increase in grasshoppers from May to September is shown in the crow's food, in which these insects constitute respectively by month 4, 6, 14, 19, and 19 percent of the food taken.
At the time of outbreaks of such insect pests the crow becomes a valuable agent in their control and herein lies the chief benefit to the farmer. Examples of isolated cases revealed the presence of 85 May beetles in one stomach, 72 wireworms in another, 123 grasshoppers in another, and 438 small caterpillars in a single crow's stomach collected in Michigan. In central Illinois I have seen large flocks of crows following the plow, where they were devouring great numbers of grubs of the destructive May beetle. It is also a common experience to see them digging up the grubs in the pasturelands where these pests were abundant. Alexander (1930) states that in Kansas the early spring crows eat enormous numbers of grubs and cutworms, which are very destructive to wheat in that State.
Nestling crows require even greater quantities of insect food than do the adults. One brood of four examined by the Biological Survey had eaten 418 grasshoppers and another brood of seven had eaten 585 of these insects; one individual had taken the record number of 143 grasshoppers. Of 157 nestlings obtained in Kansas, 151 had been fed grasshoppers. Caterpillars, always a favorite source of food for nestling birds, were present in more than a third of the 778 nestling crow stomachs examined.
The insect food of the crow is one of the strongest points in its favor and should be given proper consideration in judging the economic status of the species. The crow is an enemy of gypsy and browntail moths, but it has been observed that new colonies of moths often form about the nests of crows, indicating that these birds may serve as an agent in the spread of these pests.
Unfortunately the food of the crow is by no means restricted to insects, and among the bird's less admirable traits is its destruction of eggs and young of other species of birds, a habit that has placed the crow on the black list of many both sportsmen and bird lovers. However, these depredations, in many instances, have been greatly and perhaps willfully exaggerated in articles advocating the destruction of the crow, which have appeared in many sporting columns of newspapers and magazines. The examinations by the U. S. Biological Survey reveal that only about a third of 1 percent of the animal food of the adults and 1.5 per cent of the food of nestlings is derived from wild birds and their eggs, and only about one in every 28 crows and one in every 11 nestlings had eaten such food.
The percentage of such food, as would be expected, runs higher in crows that inhabit the proximity of nesting waterfowl. Examinations of adult crows collected in such situations in the prairie provinces of Canada show that they had eaten four times the quantity of other birds and their eggs, and the young six times the quantity eaten by crows collected in the United States. On the basis of frequency of such predation in Canada the adult crow is ten times and the nestling crow six times as bad as their fellows in the United States. This pronounced record of bird and egg destruction in Canada was due primarily to the fact that the hirds collected were taken in close proximity to nesting waterfowl, almost to the exclusion of any obtained in agricultural sections.
Observations on the Lower Souris Refuge in North Dakota in 1936 and 1937 showed that the crow is not an outstanding hazard to waterfowl there. Only 1.7 percent of the 351 nests studied in 1936 were destroyed by crows, while in 1937 the.birds preyed upon 3.4 percent of the 566 nests under observation. Even with the latter rate of loss, the crow on this refuge is at present considered to be a minor hazard to waterfowl.
Many independent observers have reported the destruction of eggs and young of both game and song birds, and there is no doubt that the crow at times is guilty of serious depredations. Baker (1940) reports the destruction of a colony of 1,500 little blue herons and 3,000 snowy egrets nesting in an island of timber known as "Live Oaks' on the coastal prairie, 9 miles south of Waller, Tex., by about 40 crows that inhabited the section. On Great Duck Island, off the coast of Maine, where I studied a colony of black-crowned night herons for an entire season, the crows destroyed 27 of the 125 nests under observation. During the season of 1940 crows proved to be a serious menace to the eider ducks nesting on Kent Island, Bay of Fundy, where' Bowdoin College has established a bird sanctuary and scientific station. On this island the crows had the habit of carrying their booty to certain convenient places to be devoured. At one such rendezvous I counted 37 eider-duck eggs and 24 herring-gull eggs and in another 22 eider-duck eggs and 28 of the gull eggs. Crows have been reported as carrying an entire egg in their beaks, but at Kent Island the egg was usually punctured by a thrust of the beak. On several occasions we observed them carrying off the downy nestlings. In August I found a place where there were more than a dozen juvenal gulls that had been killed and partially eaten, presumably by the crows. Certainly in sanctuaries such as "Live Oaks" and Kent Island, where a special effort is being made to preserve certain species of birds, the control of the crows is necessary, as it is when they become too abundant in the vicinity of nesting fowl, such as in the Prairie Provinces of Canada.
Depredations on poultry have been reported. For example, Mousley (1924) states that he saw 16 young chickens carried away by crows. Numerous reports have been published citing instances where crows have killed and eaten various species of small birds, and even birds as large as the partridge have been killed and eaten.
Such depredations, though they may call for certain measures of control, in no way warrant the total destruction of a species that has been shown to be beneficial to man's interests at other times. In the case of poultry means of protection can he readily improvised.
Of interest but of lesser economic importance is the consumption of small mammals, crustaceans, mollusks, amphibians, snakes, and carrion. Eifrig (1905) found the crop of a crow filled with earthworms. Along the seacoast, especially during the winter months, mollusks constitute a most important element of the food. It is a common practice of the crow to carry clams, scallops, mussels, or sea-urchins to a considerable height to let them fall on the rocks to be broken and thus enable them to secure the edible contents, a habit shared by other birds, notably the herring gull.
Along the New England coast, especially in Maine, I have seen groups of crows on the mud flats at low tide, where they were feeding on the myriads of invertebrates that abound there. I have also seen them feeding on dead fish left behind by the tide, and at one time seven crows were taking their turns at the carcass of a dead seal. It is not unusual to see them thrusting their beaks into the mud to secure what seemed to be a Nereis, a marine annelid worm, much after the fashion that robins retrieve earthworms from our lawns. F. H. Kennard (MS.) on July 15, 1923, saw a young crow foraging on his lawn for earthworms. For over an hour he and others observed the crow pulling up the worms. After they were pulled out the crow would stand on the worm and cleanse it with its bill before swallowing it. Brewster (1883) relates an experience of crows eating 20 good-sized trout that had been hidden in a spring. The farmers along the Maine coast complain that crows as well as gulls are a nuisance in removing fish placed on their fields as fertilizer. Ball (1938) reports similar damage in the Gasp~ region, and other complaints have come from New Brunswick and Nova Scotia.
When hard pressed crows may resort to all manner of means to obtain food. For example, Isel (1912) has seen crows enter the business district of Wichita, Kans., to feed from garbage pails back of restaurants; Crook (1936) has observed crows feeding on car-killed animals, including dogs, cats, chickens, opossums, pigs, and even skunks; Guthrie (1932) states that crows prize a dead snake as much as a living one; Anderson (1907) reports that in Iowa crows frequent the slaughterhouses to feed upon the waste of slaughtered animals; Scott (1884) observed crows feeding on a carcass of a dog while the temperature registered 140 below zero. These cases serve to emphasize the role played by crows as scavengers. They also attest the omnivorous feeding of crows and their extreme resourcefulness in securing a livelihood under adverse conditions. Such adaptability insures the success of any species in spite of persecution.
According to Kalmbach (1920) vegetable matter forms nearly 72 percent of the adult crow's yearly food, and over half of it consists of corn. Of 1,340 adult crows collected in every month of the year, 824 (over 61 percent) had fed on corn. During April and May, when the corn is sprouting, corn constitutes about a third of the food, and at the harvest in October it supplies over half of the crow's diet. The damage by the crow is chiefly to sprouting corn, corn "in the milk," or when the ripened grain has been stacked in shocks. Of the three, the second seems to be the most serious. It is not so much the corn the crow actually eats at this time but the subsequent injury resulting from water entering the ears from which the husks have been partially torn that makes the loss so important.
In 1938 the United States Biological Survey made a special investigation of the crow damage to grain, sorghums, and Indian corn growing on 210 farms comprising 39,797 acres in Grady County, Okia. The results reveal that Oklahoma has a wioter crow population of between three and four million. The damage to grain sorghums was appraised at 3.8 percent and to Indian corn 1.7 percent. The loss of these crops in Grady County alone for the year was estimated to be $18,370.
On the basis of this investigation the Biological Survey concluded that in southwestern Oklahoma there may be need of measures of control. This situation is now being met by the systematic bombing of the roosts. The case of the crow in Oklahoma is qualified by the statement that in some of the wheat:raising sections of Oklahoma the wintering crows are a benefit.
It was concluded that the crow problem, though serious to sorghums and corn in some counties, is not of sufficient magnitude in the State as a whole to demand combined State and Federal action for its solution. Kalmbach (1920) writes that in the Northwest States, where corn is not raised extensively, wheat replaces corn in the crow's diet. The damage is especially severe at the time wheat is sown or is sprouting. Oats and buckwheat are also occasionally eaten, but the larger part of these grains represents a waste product.
"Apples and almonds are less frequently injured; while the aggregate losses to beans, peas, figs, oranges, grapes and cherries are not important. Fruits of the various sumachs, poison-ivy and poison-oak, bayberry, dogwood, sour gum, wild cherries, grapes, Virginia creeper and pokeberry" are also common ingredients of the food. "The mere consumption of wild fruit by the crow involves nothing of economic importance," but the "digestive processes destroy practically none of the embryos of the seeds, and crows act as important distributors of certain plants, some of which, as poison-ivy and poison-oak, are particularly noxious.
The indigestible parts of the crow's food, such as bones, teeth, fur, and hard seeds, are regurgitated in the form of pellets as is customary with such birds as hawks and owls. An examination of these pellets gathered at crow roosts reveal interesting elements of the food eaten by any such crow population. Townsend (1918) collected several hundred pellets from a crow roost located in Essex County, Mass. These pellets amounted in bulk to 662 cubic centimeters of material after they were broken up into their composite parts. The examination of this material by E. R. Kalmbach, of the Biological Survey, revealed 13 kinds of insects and 7 other invertebrates including Melam pus, Nereis, Mytilus, and Littorina. Among the vertebrates there were fish, bones and scales of a snake, shells of hen's eggs, four meadow mice, a star-nosed mole, twc' short-tailed shrews, and large fragments of bone. There were seeds and parts of no less than 20 plants, of which the following are of special interest: 10,000 seeds of bayberry, 2,300 seeds of poison-ivy and species of sumac, 360 seeds of cranberry, and varying numbers of seeds of juniper, smilax, winterberry, grape, and nightshade. There were also very small quantities of wheat, barley, corn, buckwheat, and seeds of pumpkin or squash, apple, and pear. These results again emphasize the omnivorous feeding habits of the crow as well as its resourcefulness during adverse winter conditions.
It is important to know not only what the crow eats but also how much it eats to enable us to form a complete picture of the economic status of the species. Forbush (1907) made careful records of the food eaten by captive crows, which throw considerable light on this problem. He found that two well-grown crows fed 20 to 25 ounces of food a day just maintained their own weight, but less than that amount was not sufficient. When the quantity of food given the birds was largely reduced there was a corresponding reduction in their weight. He concluded that young crows, when fledged absolutely, require a daily quantity of food equal to about half their own weight and will consume much more than this to their advantage if they can get it. When this amount is multiplied by the number of crows in an entire population the results are impressive. Experiments on the time required for assimilation of food revealed that from the time of eating to that when the undigested parts of the food were emitted average 1Y2 hours. It is not only what they eat at a single time, but it must be remembered that the average crow gorges no less than eight to ten full meals a day. Hicks and Dambach (1935) found that the average weight of the filled stomachs of 75 adult crows was 36.6 grams and that their food contents averaged 11 grams.
The following interesting experience submitted in correspondence by R. Bruce Horsfall reveals how we may unwittingly condemn the crow when the facts are not clearly understood. Mr. Horsfall bought a farm near Redhank, N. J., where he planted five acres in corn and ten acres in asparagus. He noted that the lower end of his field, where the crows were present each day during the early morning hours, yielded no harvest. Mr. Horsfall immediately jumped to the conclusion from published accounts of crow depredations on farm crops that these birds were responsible for his loss. Without further investigation the crows were shot and the bodies left there as a warning to others. After a number of crows were killed an examination of the stomach contents revealed a mass of greenish liouid filled with cutworm heads. black beetles, and other t~nciigested materials. On the following day a visit was made to the fields in the early morning hours at about the time the crows were accustomed to be present. Great numbers of cutworms were found before they dug into shelter for the day. Mr. Horsfall thereupon decided to welcome his much-maligned friends and he had reason to regret his past hasty judgment. He placed ears of corn on the ground and left the fields to the crows. They recognized the change of attitude, returned in numbers, cleared the field of cutworms, and rewarded the owner by giving him a full yield. Since this experience Mr. Horsfall has been a staunch friend of the crow.
Forbush (1927) relates a similar experience of Gardner Hammond, of Marthas Vineyard, Mass. "Mr. Hammond owned great pastures where many sheep grazed. He told me once that he had offered a bounty of fifty cents each for Grows, as the birds had already killed about 200 of his newly born lambs, and that the native hunters under the stimulus of this bounty had killed nearly all the crows about the Squibnocket region. Notwithstanding my objection he continued to offer the bounty, although he expressed some fear that the expense would leave him bankrupt. About three years later he hailed me one day to see if I could determine what had destroyed the grass in his pastures. The grass was dead, having been cut at the roots by white grubs which had increased so rapidly after the destruction of the crows that they had already ruined a large part of the pastures. The offer of a bounty was withdrawn and the pastures gradually recovered"
Charles P. Shoffner, associate editor of the Farm Journal o~ Philadelphia, sent a questionnaire regarding the economic status of the crow to the readers of the journal who are scattered all over the agricultural districts of the United States. The results of this questionnaire are interesting, since they present a cross section of public opinion of a group of citizens most vitally concerned in the problem. Some of the replies were copied directly from the reports of the Department of Agriculture or other sources, but 9,731 were selected as being apparently based on personal observation or opinion. Among these 1,801 were in favor of the crow and 7,829 against him. Of the latter, 7,573 replies charged damage to crops, 6,937 to poultry, 4,112 to young pigs, sheep, rabbits, etc., 6,796 to song birds, and 6,493 to game birds. As Mr. Shoffner truly says, due weight must be given to the fact that reports were solicited by mail and it would be natural for farmers who had suffered serious damage to write their disapproval, while those who had suffered little or no loss would not trouble to do so. The interesting point is that so many persons defended the crow.
The conclusions of the Journal were:
1. The Crow wherever found in large numbers is injurious to farmers from March to December.
2. Where Crows are numerous they should be reduced in numbers and this should be done under active cooperation of State or National Agricultural Authorities. The Crow need not be exterminated.
3. The good Crows do by eating insects does not compensate for the damage done by eating eggs and young of other birds.
4. In acting as scavengers, Crows carry disease; farmers should bury or burn at once all dead animals.
There is a great difference in local conditions. In the West crows are a serious menace, while in parts of the East they are neutral or actually beneficial. Of the conclusions arrived at by the Farm Journal, those who have studied the economic relations of the crow will take exception to conclusion No. 3.
(For further comment on this questionnaire, see The Auk, vol. 43, pp. 140-141, 1926.)
Behavior: The crows return to their roosting place early in the afternoon. The flight then is high and quite direct. Various estimates have been made of their speed in flight. Grows have been known to keep up with trains running at the rate of 60 miles an hour, but the speed determined by Townsend and others indicates that under ordinary conditions it seldom exceeds 20 to 30 miles an hour. If this rate is correct then a crow during sustained flight of a 10-hour day would cover only about 250 miles. Ducks, according to Lincoln (1939), travel 400 to 500 miles in the same period.
Townsend (1905) in writing of his experiences with crows in winter at Ipswich, Mass., records some interesting incidents as follows: "Hearing a great outcry among a party of Crows one day at Ipswich, I saw several swooping down to within a few feet of a fox. Reynard seemed not a whit disturbed, and carried his brush straight out behind as he sauntered along. * * * I have heard them make a virtuous outcry over a couple of innocent hares that were running through the dunes.
"Tracks show that it is a common habit for Crows to drag their middle toe in walking and sometimes all three front toes are dragged. Again, tracks of the same or other Crows show that the toes are lifted up without any dragging. I have seen Crows hop, and have found evidence of that in the sand. In landing from the air, their tracks show it is often their habit, to bound or hop forward once with feet together, before beginning to walk"
Some observers have stated that the crow in flight carries its feet extended backward, but F. H. Kennard, in some unpublished notes, records an observation made under favorable conditions. He was very near a crow that was silhouetted against the snow as it took flight. It raised its legs, after dangling them straight, directly up under and flew off with the closed claws showing as two lumps barely projecting from the feathers of the lower breast.
The feet of the crow are not well adapted for grasping, and their appearance would not at all suggest that they are prehensile, yet these birds do at times carry fairly large objects by means of their feet. At Kent Island I saw a startled crow grasp an eider duckling in its claws and transport it to cover in a thick growth of spruces. Chamberlain (1884) observed crows carrying two young of a brood of robins in their claws, and Kneeland (1883) has seen crows carrying fish heads and other objects too large and too heavy to be conveniently carried in the bill yet too precious to be left behind when food is scarce, as it often is during the winter. Chamberlain also saw a pet crow seize a partially eaten ear of boiled corn in its claws and fly away with it when accosted by a barking dog. Fred J. Pierce (1923), in an article entitled "A Crow that Nearly Looped the Loop," presents the following interesting observation: "I noticed a Crow flying overhead carrying an article in his feet that looked like a mouse or something of that sort. This Crow wanted to transfer the morsel to his bill, and in trying to do so bent his head underneath him so far that he lost his balance and barely escaped overturning in the air. This must have surprised him considerably, but he was a determined Crow and shortly tried it again with no better success. He was continuing his vain efforts when lost to view, but as his unsteady flight had brought him very near the ground, he doubtless alighted, ~vhere his object was accomplished with much less danger to his equilibration"
The adult crow is very wary and suspicious of man, an instinctive behavior for self-preservation that has been acquired through generations of experience. Yet crows taken from the nest at the proper time have become pets that have exhibited the greatest confidence in their companionship with human beings. There are innumerable instances on record in which crows have proved to be interesting and entertaining pets.
Lorenz (1937) has pointed out that a young bird, when reared under artificial conditions, will invariably react to its human keeper in exactly the same way that it would have reacted, under natural conditions, to birds of its own species. He has also stated that the period of acquiring this imprinting is confined, in some species, to a very definite and often astonishingly brief period, and that certain actions of the bird for the remainder of its life depend on the imprinting during this crucial period.
Cruickshank (1939) in testing out the statements of Lorenz, contrasts the hehavior of two crows that he kept as pets. The first was taken from the nest when it was only two weeks old. It was raised in his home with great attention and soon reacted to him and his wife as it would have to its own parents if left in the wild. The crow followed them about, fluttering its wings and excitably begging for food. After it had learned to fly it paid no attention to local wild crows or to other human beings about the camp, but would single out Mr. Cruickshank or his wife and follow them everywhere. The food-begging act was performed for them only. The appearance of either of them or the sound of their voices was sufficient to start its begging. In various other ways this pet crow showed that it had thoroughly accepted its human foster parents and rejected all others. The other crow, obtained a few years before, had been taken on the day it left the nest. Though kept in isolation for the ensuing two weeks this crow never accepted Mr. Cruickshank in any way. His appearance never released the begging act, and the bird was always interested in the calls of nearby crows. At the first opportunity it flew off into the woods and never returned. This individual evidently had been obtained at too late a period. The imprinting had already taken place, and even close attention and strict isolation did not initiate a reverse.
The above experience readily explains the varying success persons have had in attempting to make pets of crows. Many have written about their pet crows, but one of the most detailed accounts is presented by Norman Criddle (1927), who had four crows that he obtained near Treesbank, Manitoba, on June 19, 1926. These birds exhibited considerable fear when first obtained, and it was necessary to feed them by force, but after a day they strongly exhibited the begging reactions. They greeted his approach by enthusiastic cries for food and their fear of man had vanished. Later, when able to fly, they were allowed to roost among the trees, hut in the morning they collected around the feeding cage and his approach was always greeted with enthusiasm. They would alight on his head and shoulders as readily as on any other perch. During the day the crows devoted much of their time collecting and hiding objects of various kinds. As they grew older, berries and other food were hidden with the definite object of using it later when hungry. One of the crows would alight on its foster parent's shoulder, pull out the pocket handkerchief, deposit a throatful of berries, and then carefully shove the hankerchief back into place on top of them. The love of destructiveness became a dominant trait. Newspapers and brightly colored flowers in the garden were pulled to small bits, and other objects were similarly treated. When a pan of water was provided they soon took to bathing, although they had never experienced water before. Bathing and playing in the water became a regular pastime. Sometimes, after flying to Mr. Griddle's shoulder, they would playfully pinch his ear or run their beaks through his hair. One of theni repeatedly tried to dislodge the button from his cap. Each of the crows was different in its personality and details of behavior. Mr. Criddle presents a multitude of experiences indicating that these crows performed just as they might have done toward their own kind if left in nature.
Pet crows are known to possess unusual ability to articulate the words and imitate the sounds of the human voice. They readily master such simple words as "mama," "papa," "hello," "howdydo," and others, and human laughter is often imitated to perfection. This presents the question as to how the crow is able to articulate and imitate so well. We should not expect to find the tracheal syrinx and its controlling muscles to be well developed in a bird that is not recognized for its ability to sing. To the contrary, the crow has a complete set of voice muscles. It is these muscles that give parrots and certain passerine birds such a variety of vocal modulations, so that they can mimic other birds or even the human voice. Hence it is not at all surprising that crows exhibit this unusual ability of imitation.
Pet crows are known to be very adept at learning and to meet new and previously inexperienced conditions. Coburn (1914) has proved this ability experimentally. He found that crows learn very quickly to distinguish the correct exit door when placed in a dark box from which there were translucent and lighted exits, each of the same area and light intensity but of different shapes. In this way it was shown that they distinguished with very little practice between a circle, a triangle, a square, and a hexagon. In this and other tests the experimenter was convinced that the crow's reputation for brains is quite deserved, and that Henry Ward Beecher was correct when he said that if men could be feathered and provided with wings, very few would be clever enough to be crows! Voke: The crow does not excel in its musical ability, but it has a great versatility in its voice. It has an interesting repertoire of many calls and notes, which serves it well in its interrelations with its fellows. It also has superior imitative faculties, and captive crows have exhibited unusual aptitude in learning new calls. Even human laughter is imitated, at times so appropriately tittered that it is difficult to think of it as mere coincidence.
The calls and notes have been subject to diverse interpretations; hence several representative authors have been quoted to present a betterrounded concept of them. Hoffmann (1904) states: "Besides the ordinary caw, and the many modifications of which it is capable, the crow utters commonly two other striking notes. One is a high-pitched laugh, ha-~-~-~-a-~; the other a more guttural sound like the gobble of a turkey, c~w c3w c6w." Knight (1908) interprets the various calls of the crow as portraying signals that have a distinct meaning to their fellows:
When a band of crows is feeding one or two are generally posted as sentinels and a caw c-a-a-w of warning from these is sufficient to make all seek safety. Their call caw-caw is uttered in varied tones and different accents so that it is capable of meaning a great many things from alarm to satisfaction, and one acquainted with their ways can usually tell just what they are saying in a general way. For instance I have never failed to correctly judge from their excited and confused cries that they had an owl penned up somewhere and were engaged in "mobbing" it to their satisfaction. The alarm "caw" uttered sharply and quickly, which means "look out" is well known to about everybody who has ever seen a Crow. Their prolonged cries of distress when their home is menaced should be easily recognizable. The prolonged car-r: : -: : --a: : : --: -c--: : --k of a love sick individual in spring, uttered in various tones and drawn out into prolonged gurglings, though somewhat like the call of the young for food is still quite different.
Forbush (1927) writes:
Some Crows, if not all, are capable of producing unusual, tuneful or pleasing sounds. As an example of the unusual let me refer to an individual that I heard early one morning on Cape Cod repeating for over an hour syllables like clockity-clock, clockity-clock; while as showing the musical attainments of the species mention may be made of a Crow that I saw on the banks of the Musketaquid, August 10, 1906, which uttered a series of exceedingly melodious, soft, cooing notes unlike any others within my experience. In the same locality on July 14 a young Crow remarked very plainly aaoou, cou, cou, cou, aaaou, coucoo. On October ~), 1903, I heard and saw a Crow give an excellent imitation of a whine of a dog. * * * ~ have heard from Crows a varied assortment of notes, some of which apparently were imitations, such as the cry of a child, the squawk of a hen, or the crow of a young rooster. The cooing notes mentioned above were similar to sounds uttered by the male in courtship. At this season, also, the male has a peculiar cry which may be an attempt at song and has been represented by the syllables hollow-ollo-ollo.
Townsend (1923) gives the following account of the calls of the crow:
There are many other words in the Crow vocabulary than the simple cow, and I find a number of them recorded in my notes. Many are common and familiar sounds of the countryside, and their recognition is always a pleasure. First, one may consider the modifications of the cow. Of these, orr, orr, are common, as well as ah, ah, the latter delivered at times as with a great feeling of relief. Again, the note may sound like gnaw, gnaw, delivered with a nasal inflection and in a taunting manner.
On the other hand the notes may lose all semblance of the typical cows, and rapidly repeated and wailing koo, Wha, wha, who, kao, wha, who, who, may be heard, or, as I have written at other times, ou, a/Is, ahh, oh/i. Again, a loud and cheerful ha, ho, ho, may be heard, suggestive of one of the calls of the Herring Gull. A despairing ,sevah, ,ievah, is not uncommon. Occasionally one may hear a loud cluck. One of the most extraordinary combinations of Crow nAes that I have ever heard was emitted near my house at Ipswich early one April morning. The bird called chuck-chuck, u'hoo-oo, and then cawed in the ordinary manner, repeating the formula in this order several times. Its significance was bidden.
The conversational notes of a small group or family of Crows are always entertaining, and the observer is impressed with the extensiveness of their vocabulary and with the variations in their feelings. At times the notes are low and confidential, pleasant and almost melodious, if I may use that word here; again they are raucous and scolding, bursting at times into a veritable torrent of abuse. In the same way, in human conversations, one may, even without understanding the words, be able to interpret the meanings and motives involved. [See under Courtship for additional notes.]
Allen (1919) has called our attention to the time rhythm, which he attributes to a well-developed esthetic sense of the crow. He has noted that the caw notes are not only in triplets but at times they give four cows in groups of two (2-2); again he noted that the bird cawed 2-1 a large number of times in succession and on other occasions 2-1-1. The time was so regular that he could detect no variations. The length of the several notes and their pitch and quality were uniform, the rhythm being all that differentiated the phrase from other performances of the crow.
Allen does not believe the series of combination of calls represents a code of signals, nor does he believe them to be purely mechanical and involuntary, but he thinks the crow takes delight in the rhythm and variety of his utterances. He asks the question, "Is he not, in a limited way, a true artist, a composer as well as a performer ?" Wright (1912), in a study conducted at Jefferson Highlands in the White Mountains, N. H., determined the order and manner in which summer resident birds within range of hearing awoke and voiced themselves. According to Wright the crow is a comparatively late riser, as it ranks twenty-fourth among the common birds in time of voicing itself. Fourteen records show that the earliest times at which a crow was heard to call were 3:35 and 3:36 A.M. The average time of the first call was 3:44 A.M. The variations of the crow's awakening was only 21 minutes on 14 occasions, ranging in date from May 27 to July 9, and covering ten seasons. Wright concluded that the crow was one of the most regular in awakening of the common birds he observed.
Enemies: The crow is recognized as an enemy of certain species of birds, especially in the destruction of their eggs and young, but it is itself in turn preyed upon by hawks and owls. Homed and snowy owls have been seen to capture and kill crows, and the remains have been found in the stomach contents of others. Likewise remains of crows have been found in the stomach contents of red-shouldered and red-tailed hawks and goshawks, and probably the crow falls a victim to other species of the larger hawks. Even the smaller species of hawks may sometimes exhibit a daring inclination to tackle a crow. White (1893) relates an experience in which the small sharp-shinned hawk was seen to attack successfully a crow on Mackinac Island, Mich. Sutton (1929) found the crop of a Cooper's hawk, killed near Shippensburg, Pa., packed with feathers and flesh of a crow. According to the observer a second Cooper's hawk was seen to fly up from the spot where the first was killed, and nearby among the weeds was a partly eaten and fairly well plucked crow, the flesh of which was still warm. Dr. Sutton, although admitting he is unable to prove the case, believes that one or both of the hawks killed the crow.
It is well known that even smaller birds, notably the kingbird, may harass a crow and make its existence very uncomfortable. Currier (1904) in an account of crows observed at Leech Lake, Minn., writes: "One pair in particular had our sympathy. They had a nest full of young in a scrub oak standing alone out on the marsh, where several pairs of Kingbirds, and thousands of Redwings were breeding. Every time a Crow made a move it was pounced upon by from two to a dozen of the smaller birds and forced to light for a time. The Yellow-heads would also join in at times, but they were not so persistent. The Redwings seemed to be the worst"
I have seen crows that have chanced to enter sea-bird colonies viciously and violently attacked by terns.
That crows are never on good terms with predaceous birds, especially owls, is evidenced by the great commotion aroused among the crows whenever an owl is discovered. Fortified by numbers, they exhibit great audacity and may harass an owl for hours at a time. In fact, the presence of an owl may frequently be revealed by the cawing and behavior of the crows at such times. Their antipathy for owls is so great that they may be lured by a stuffed owl placed by a gunner who wishes to destroy them. For the past 15 years I have had several live horned owls in a large flight cage in the backyard of my home in Brunswick, Maine. Almost every morning during the spring migration, flocks of crows ranging from a dozen to 25 or 30 alight in the surrounding trees and awaken the entire neighborhood by their haranguing calls. The crows alight on top of the cage but the least movement on the part of the owls sends them scampering to the tree tops under loud protests. Seeking renewed courage the crows descend again and again to repeat the performance. This goes on in spite of the fact that it is in the midst of a thickly settled portion of the town.
Crows, as well as other birds, fall as victims of flesh-eating mammals. Errington (1935) in his study of the food of midwest foxes, reports that crows are eaten by them.
Wilson (1923) reports a case in which a crow was attacked by a large snake, but such instances are probably rare.
Among mammals, the crow's greatest enemy is man. Since the economic status has been questioned thousands of crows have been killed by poisoning, shooting, and especially by bombing the populous roosts. A few are killed on the highways by automobiles.
No comprehensive study of the diseases of the crow has been made to my knowledge, but as has been shown in the case of other species of birds, disease is probably an important factor in the life of the species.
Mitchell (1929) reported an epidemic of tuberculosis in crows of western Ontario, where he conducted experiments to see if infection is likely to be carried to other animals. Eaton (1903) has given us a detailed report of an epidemic of roup in the Canandaigua crow roost in Ontario County, N. Y., during the winter of 1901-2. Eaton estimates that at least a thousand crows succumbed to the disease in that region alone. Dr. Fox (1923) in a pathological examination of 16 crows, found cases of tropidocerca, occasional intestinal cestodes, and a few filaria.
Dr. E. B. Cram (1927) lists five internal nematode parasites found in the crow. Three of these are found in the proventriculus, the glandular part of the stomach, and the other two in the trachea, or lungs. The parasites are as follows: Acuaria cordata (Mueller), found in the wall of the proventriculus; the males range from 10 to 11 and the females 22.5 to 40 millimeters in length. Microteframeres helix Cram, found in the walls of the proventriculus; the males of this small worm are 4.9 and the females 1.2 to 1.3 millimeters in length. Tetrameres imis pine (Diesing), known only from the female, which is 3 millimeters in length; this parasite is found also in the proventriculus. Syngamus trachea (Montague), occurring as adults in the trachea and bronchi and as larvae in the lungs; immature worms have been found in the peritracheal tissue and air sacs; the males are 2 to 6 and the females S to 20 millimeters in length. Syngamus gracilis Chapin, found only in the trachea; the males are 3 to 3.3 and the females 8 to 11 millimeters long.
Harold Peters (1936) lists three lice and one tick as common external parasites of the crow. The lice are Degeeriella rotund eta (Osborn), Myrsidee americana (Kellogg), and Philopterus corvi (Osborn) and the tick is I-Iaemaphysalis leporis-palustris Packard. A different species of tick and two species of mites have been found on the southern crow. The tick is Atublyomma americanuns (Linnaeus), found in a crow from South Carolina, and the mites are Liponyssus sylviarum (Canestrini and Fanzago) and Trouessartia corvina (Koch), found on crows collected in South Carolina and Florida, respectively.
But by far the worst enemy of the crow is man. Where crows are numerous, especially in their winter roosts, enormous numbers are killed by bombing with dynamite. As one example of this, Dr. Walter P. Taylor (MS.) tells us that in Collingsworth County, Tex., on April 7, 1937, bombs were exposed in a shinnery clump to kill crows. There was one stick of dynamite to each bomb, and the bombs were connected with wires, so that they could be fired simultaneously. Sixty bombs were set off at the first discharge, at which it was estimated that 40,000 crows were killed; at the second shot, 120 bombs were set off, killing nearly as many more. Other bombing operations are mentioned under "Roosts"
Roosts: During the summer crows associate only in pairs at their isolated breeding places, but in fall they exhibit a marked gregarious inclination, and birds from many miles of territory congregate in immense roosts comprising thousands, sometimes tens and even hundreds of thousands, of individuals. These roosts are not only made up of the birds breeding in the region but the flocks are augmented by birds that have migrated from nesting grounds located farther to the north. In New England there is a marked tendency for the crows to move from inland areas to roosts established near the coast. Food is the primary factor involved in this shift; whereas the feeding grounds in the interior become covered with snow and ice, the seacoast provides an uninterrupted food supply that is replenished with every flow of the tide. Even the severe winter weather does not drive the hardy members from the roosts established in the dense coniferous forests that fringe the coast. Most of the roosts in northern New England are comparatively small, however, and one must go farther to the southward before meeting with aggregations of unusual size.
Townsend (1918) has presented a vivid account of a crow roost that contained approximately 12,000 individuals, located in the thickets and hardwoods on Castle Hill near Ipswich beach, Mass. Following are extracts from Dr. Townsend's paper, which portray in detail scenes similar to those many others have experienced.
In the short winter afternoons the Crows begin their flight to the roost long before sunset. By three o'clock or even as early as one o'clock, especially in dark weather and in the short December days, this bed-time journey begins, while in the latter part of February the flight is postponed until half past four or a quarter of five. From every direction but the seaward side the Crows direct their course towards the roost. Three main streams of flight can be distinguished: one from the north, from the region of the Ipswich and Rowley "hundreds,": the great stretches of salt marshes that extend to the Merrimac River,: a second from the west and a third,: apparently the largest of all, broad and deep and highly concentrated,: froni the south.
It was the last of these rivers that on a cold December afternoon with a biting wind from the northwest I first studied. * * * It was an impressive sight. About 3 o'clock the Crows began to appear, singly and in small groups, beating their way in the teeth of the wind towards the north. In flying over the estuary of the Castle Neck River they kept close to the water as if to take advantage of the lee behind the waves; over the land they clung to the contour of the dunes. As we walked among these waves of sand the Crows often appeared suddenly and unexpectedly over the crest of a dune within a few feet of us. Silently for the most part, except for the silken rustle of their wings, they flew over in increasing numbers until it was evident that they were to be counted, not by hundreds, but by thousands. Many of them alighted on the dunes to the south of the roosting place; sand, bushes and stunted bare trees were alike black with them. Others assembled on the bare hillside to the east. About sunset a great tumult of corvine voices issued from the multitude,: a loud cawing with occasional wailing notes,: and a black cloud rose into the air and settled in the branches of the bare trees to the west of the roost. From here as it was growing dusk they glided into the evergreens for the night.
The last day of the year 1916, I spent with Dr. W. M. Tyler in the dunes. The wind was fresh from the northwest,: the temperature was 15 Far. at 6 :30 A.U., 180 at noon and 200 at 6 P.M. As early as one o'clock in the afternoon a few Crows were seen struggling north over and close to the surface of the dunes. Others were noticed flying high and towards the south. This southerly flight came from over Castle Hill to the north, passed the roost and continued on over the dunes. At half-past three some of these birds, which were apparently turning their backs on their usual night's lodging place, met with a large company coming from the south and all settled together in the dunes about two miles south of the roost. Some of the birds coming from the north, however, settled in the bare fields by the roost, and their numbers here were augmented by a stream from the west. This concourse on the hillside set up a great tumult of cawings just before four o'clock. At five minutes after four the united multitude of northerners and southerners rose from their meeting place in the dunes and flew low to join their noisy brethren on the hillside. This river of black wings from the south was a continuous one and it was joined just before its debouch on the hillside by the stream from the west. The river from the north had split into two layers: the lower flying birds came to rest on the hill,: the higher flying ones favored by the strong northwest wind, continued on their way south, notwithstanding the great current that was sweeping north below them. They joined their comrades in the dunes and retraced their steps. No signs of starvation and impaired vigor in these unnecessary flights, or in the game of tag in which two or more of the birds at times indulge I The pace is now fast and furious. The birds are anxious to get within touch of the roost before it is dark but none have yet entered it. At 4:15 P.M., 135 birds pass in a minute from the south alone on their way to join the concourse on the hillside. A little later this southern river becomes so choked with birds that it is impossible to count them. From our point of vantage in a spruce thicket on the hill we can see that this flock stretches for two miles into the dunes and it takes them four minutes to pass. The speed of flight, therefore, must be roughly about thirty miles an hour. At 4:15 P.M. the sun sets, but in the yellow glow of the ck~udless sky the birds can be seen pouring by from the west and south. The bulk of the stream from the north now comes to rest on the hillside for only occasionally can a crow be seen flying to the south over the heads of the southern stream.
At 4:35 P.M. Dr. Tyler and I again counted the southern stream for a minute as they flew silently between us and the lighthouse. One of us counted 160 the other 157 birds, so it is probable that our counts are fairly accurate. This constant watching of the black stream from the south against the white lighthouse produced in both of us a peculiar optical illusion. The lighthouse and dunes seemed to be moving smoothly and swiftly from north to south I At 4:37 P.M. a great cawing arose from the hillside and a black cloud of birds rose up, some to enter the roost, others to subside on the hillside. It was evident that the birds from time to time had been diving into the roost. At 4 :40 P.M. it was rapidly growing dark and the tributary streams were evidently dwindling. Only 50 went by the lighthouse in a minute. Five minutes later it was nearly dark and only a few belated stragglers were hurrying to the concourse on the hill.
At 4:45 P.M. Dr. Tyler and I walked around to the north of the roost and although we could see nothing in the darkness we could hear the silken rustle of wings and feathers as the Crows were composing themselves for the night's rest among the branches of the trees. The babble of low conversational notes that went up from the company suggested the sounds of a Night Heronry although cawings and carrings were interspersed with the kis and uk., and oh/is. * * *
In the dim light we could make out that the hillside field between the roost and the sea was still blackened with birds that were continually rising up and entering the trees. Some of them perched temporarily on the bare tops of the hard woods where they were visible against the sky. The noise and confusion were great. It would seem as if the roost was so crowded that the birds had to wait their time for a chance to get in and that a constant shifting of places and crowding was necessary before the Crows could settle in peace for the night. Hence the prolonged varied conversation; hence the profanity.
It was an intensely interesting experience, this observation of the return of the Crows to their night's lodgings, and one wished for eyes all about the head, well sharpened wits to interpret and a trained assistant to take down notes. * * *
At the full of the moon on the sixth of January I visited the roost at 9 P.M., a time when all well regulated Crows should, I had supposed, be sound asleep. As I approached the roost much to my surprise I heard distinct sleepy cries like those of young herons, and when I reached the edge of the roasting trees there was a tumultuous rush and bustle of Crows flying from tree to tree and overhead. Strain my eyes as I would only occasionally could I catch sight of a black form, although the air was brilliant with the moonlight and the reflection from the snow. I turned back at once as I had no desire to disturb the birds' slumbers but it was evident that many, even at this late hour, had not settled down for the night.
The morning flight from the roost takes less time than the evening return. As I approached it in the semi-darkness at 6:25 AM. on January 7, a distant cawing could be heard and a minute later nine Crows were seen flying off to the south, and three minutes later, nine went off to the west. At half past six, after a great uproar of cows and uks, occasional rattles and wailing ahjshs, a broad stream boiled up from the roosting trees and spread off towards the west, obscurely seen in the dim light except when the birds stood out against the beginning red glow in the east or against the light of the setting moon in the west. As I stood concealed on the hillside among a grove of spruces, the Crows passed over my head, noiselessly except for the silken swish of their wings, fully a thousand strong. Then no more for over five minutes although the tumult in the roost continued in increasing volume. At 6:40 the roost boiled over again, but the birds spreading in all directions soon united into a black river that flowed over the dunes to the south. The settings of this black stream were the white sand dunes and the luminous glow in the east which had become a brilliant crimson fading to orange and yellow and cut by a broad band of pink haze that streamed up to the zenith. The morning star glowed brightly until almost broad daylight. The sun rose at 7:14. At 7 I entered the roost and hurried away the few hundred remaining birds some of whom were in the bare tops of the hardwoods ready to depart, while others were still dozing in the evergreens below.
Nuttall's Ornithology (1832) gives an account of two roosts on the Delaware River in Pennsylvania. One of them was on an island, near Newcastle, called the Pea Patch, a low flat alluvial spot, just elevated above high-water mark, and thickly covered with reeds. The crows took shelter in the reeds and at one time during the prevalence of a sudden and violent northeast storm accompanied by heavy rains, the Pea Patch Island was wholly inundated in the night. The crows apparently made no attempt to escape, and were drowned by thousands. The following day the shores for a distance of several miles were blackened by their bodies.
Stone (1899) states that the crows that inhabited Pea Patch and the neighboring Reedy Island were estimated at 500,000.
Another famous crow roost is one located in Brookland, near Washington, D. C., which accommodates practically all the crows that feed in the vicinity. Oberholser (1920) estimated that this roost contained 200,000 birds. A very large crow roost was located at Arlington, Va., across the Potomac from Washington. Dr. W. B. Barrows estimated that 150,000 to 200,000 crows came to it every night during the winter of 1886-87.
Widmann (1880), in connection with an account of a crow roost located on Arsenal Island opposite the southern part of St. Louis, writes: "As early as August they begin to flock in, first by hundreds, then by thousands, and in December hundreds of thousands sleep there every night. The roar they make in the morning and evening can be heard for miles around, and the sight of the influx of these multitudes in the evening is something really imposing." Later Widmann (1907) in writing about this roost stated: "All through fall and in moderately cold weather in winter, the Crows spent the nights perched ten to fifteen feet above the ground in the willow thicket of the island, but when the cold weather became intense they deserted the willows entirely and spent the nights on the snow-covered sand bank in front of the willow thicket and exposed to the fierce northwest and north wind. When they had gone in the early morning, every bird had left an imprint of its body in the form of a light depression in the snow with a hole in front made by the bill and a few heaps of excreta on the opposite side, showing the bird had spent all night in that position, always with the head turned toward the wind, letting the wind sweep over its back, but keeping the feet from freezing"
Although crows are very resourceful in combating the adverse weather conditions of winter, extreme subzero temperatures have been known to play havoc with them at the roosts. J. W. Preston wrote Bendire (1895) of a roost of 40,000 crows located near Baxter, Iowa, in which many of the birds died of starvation during the cold winter of 1891-92 because they were blinded from the freezing of the corneas of their eyes. Likewise, Ridgway in Science, February 10, 1893, p. 77, mentions the sufferings of the crows in a roost near Washington, D. C. He states that many had their eyes frozen, which was followed by the bursting of the organs and the consequent death of the birds from starvation.
Crows have probably evolved the habit of congregating in roosts for mutual protection, but in the present day, since the verdict concerning their relations to man's interests in certain States has been pronounced against them, thousands of individuals are killed by man at the very roosts where they sought refuge against danger. Imler (1939) states that 26,000 birds were killed by the bombing of a large crow roost near Dempsey, OkIa., on December 10, 1937. The Game and Fish Commission bombed another roost at Binger, OkIa., on December 6, 1938, killing 18,000 crows. Frank S. Davis, inspector for the Illinois State Department of Conservation, killed 328,000 crows in roosts near Rockford, Ill., with the use of festoons of dynamite bombs. This wholesale slaughter was given great publicity, appearing with photographs in the issue of Lije for March 25, 1940. Numerous roosts throughout the winter range of the crow in the Middlewest and South have been dealt with in a similar manner. In addition to shooting and bombing, poisons also have been employed. This unprecedented destruction of bird life has been received with both commendation and violent criticism. Some of the larger roosts numbering hundreds of thousands of individuals provide us with one of the most spectacular scenes of bird life. It is indeed unfortunate that departments of conservation find it necessary to destroy them.
Winter: Along the New England coast winter is one of the most interesting seasons for a study of crows. At this time they are more numerous than during summer, since the snow-bound conditions of the interior bring them to the tidal shores, where there is a more accessible and constant food supply. They may be seen leaving the roosts early ill the morning, often before sunrise, in groups of two or three to a dozen or 20. At this season they seem to lead an aimless kind of existence, meandering here and there, flying low over the mud flats or open fields in a persistent search for food. Sometimes their wanderings take them long distances, going hither and thither until a carcass or other food supply is located. At all times they are alert and suspicious, always proceeding toward food with caution, often alighting on convenient vantage points to carefully inspect the surroundings and to make sure no harm is in store for them. Finally an individual more audacious, perhaps hungrier than the others, approaches to test out the situation. If he succeeds in escaping harm the others quickly join him in active competition to gorge themselves. At such times one bird may act as a sentinel to give warning in the event of approaching danger.
Edward J. Reimann in correspondence concerning crows seen in winter in the vicinity of Philadelphia, Pa., writes: "Crows in winter, especially when ice has formed in the waterways, ~vill be found frequenting the low flats of streams and cyeeks left bare by the low tide. They can be seen congregated in immense flocks feeding on the seeds of arrow-arum (Peltandra virginica). When the rivers are full of drift ice, crows seem to take a particular delight in perching on the cakes and traveling up and down stream with the tide. On some occasions crows were seen to be eating fish frozen in the ice"
DISTRIBUTION Range: Most of North America; migratory in the northern regions. Breeding range: The crow breeds north to Alaska (probably Kodiak Island, Seldonia, and Hinchinbrook Island); southern Mackenzie (Fort Simpson and Grandin River); southern Keewatin (50 miles south of Cape Eskimo); southern Quebec (Onigamis, Godbout, and Mingan Island); and Newfoundland (probably Port au Port and St. John's). The eastern limits of the range extend southward along the Atlantic coast from Newfoundland (St. John's) to southern Florida (Royal Palm Park and East Cape). The southern limits extend westward along the coast of the Gulf of Mexico from southern Florida (East Cape) to Texas (Houston and Kerrville); northern New Mexico (Glorieta, Santa Fe Canyon, and Santa Clara); central Arizona (White Mountains and the Salt River Bird Reservation); and probably northern Baja California (Guadalupe). West to probably Baja California (Guadalupe); California (San Diego, Buena Vista Lake, Stockton, and Red Bluff); Oregon (Warner Valley and Silver Lake); Washington (Camas, Westport, and Everett); British Columbia (Stanley Park, Gull Island, and Massett); and Alaska (Forrester Island. Sitka, and probably Kodiak Island). The crow is also resident in Bermuda.
The range as outlined is for the entire species, which is now separated into four geographical races. The eastern crow (Corvus brachyrhynchos brachyrhynchos) is found from Maryland, the northern parts of the Gulf States, and northern Texas north to Newfoundland, Quebec, northern Manitoba, and southwestern Mackenzie; the southern crow (Corvus b. paulus) occupies the southeastern part of the range (except Florida) west to eastern Texas; the Florida crow (Corvus b. pa.scuus) is found only in the Florida Peninsula; the western crow (Corvus b. hesperis) occupies the western part of the range north to southern Saskatchewan and central British Columbia.
Winter range: Resident throughout the southern part of the breeding range and north to southern British Columbia (Comox, Chilliwack, and Okanagan Landing); southern Saskatchewan (East End); southern Manitoba (Portage la Prairie); southern Ontario (Sault Ste. Marie, North Bay, and Ottawa); northern Vermont (St. Johnsbury); Maine (Avon and Ellsworth); New Brunswick (Scotch Lake and Fredericton); Nova Scotia (Wolfville and Pictou); and southeastern Newfoundland (St. John's).
Migration: Since in winter the crow is found in limited numbers, as far north as southern Canada, dates of arrival and departure do not convey a true picture of its migrations. Extensive migratory flight is, in fact, confined to the birds of the Great Plains region. In the files of the Fish and Wildlife Service there are several hundred instances of crows banded during the summer in Saskatchewan that were subsequently recovered during the following fall and winter at well-connected series of localities south through North and South Dakota, Nebraska, Kansas, Oklahoma, and Texas. Similarly, crows banded during winter in Oklahoma and Kansas were recovered during the following spring and summer north through Nebraska and the Dakotas, to Manitoba, Saskatc~hewan, and Alberta. Crows banded at northern points on the Atlantic coast show very little movement but are generally recovered within 100 miles of the point of banding.
Egg dates: Alaska:1S records, May 10 to June 11; 8 records, May 17 to June 6, indicating the height of the season.
Alberta: 21 records, May 2 to June 9; 10 records, May 13 to 24.
British Columbia: 10 records, April 17 to June 4. California: 112 records, March 21 to June 12; 56 records, April 9 to 21.
Florida: 52 records, January 21 to May 27; 26 records, February 26 to April 2.
Illinois: 39 records, Marcji 27 to May 22; 19 records, April 9 to 27.
Kansas: 22 records, March 3 to May 15; 11 records, April 3 to 19.
Maine: 60 records, April 16 to May 27; 30 records, April 28 to May 8.
New Jersey: 146 records, March 30 to June 12; 74 records, April 15 to May 7.
Ontario: 12 records, April 14 to July 5; 6 records, April 25 to 30.
Oregon: 17 records, April 16 to May 27; 9 records, April 29 to May 11.
Texas: 9 records, February 28 to April 26.
West Virginia: 27 records, April 5 to May 28; 13 records, April 12 to 19.
Washington: 6 records, April 22 to May 22.
SOUTHERN CROW CORVUS BRACHYRHYNCHOS PAULUS Howell
This southern race was named by Arthur H. Howell (1913) from a type collected in Alabama and described as "decidedly smaller than Corvus b. brachyrhynchos, with a much slenderer bill. Nearest to Corvus b. hesperis but with shorter wing and slightly larger bill." He says further: "Although the bird is nearest to C. b. hesperis in size, its range apparently is separated from the range of hesperis by a strip of country in central Texas in which no crows breed." He gives as its range "Alabama, Mississippi, Louisiana, southeastern Texas, Georgia (?), South Carolina, and north to the District of Columbia and southern Illinois." It evidently intergrades with brachyrhynchos at the northern and western limits of this range. He also says that it is decidedly smaller than the Florida crow, pascuus, which is rather remarkable, as Florida races of other birds are generally smaller than the more northern races.
I cannot find that the habits of the southern crow are materially different from those of the eastern crow on the one hand, or the Florida crow on the other hand, depending on the conditions in which it lives. It builds similar nests in many different kinds of trees and feeds on similar classes of food. It has some of the bad habits of the northern race but is nowhere so abundant as to do much damage, and it destroys so many injurious rodents and noxious insects that it probably does more good than harm and should not be molested.
M. G. Vaiden writes to me: "These birds are not so plentiful in the Yazoo-Mississippi Delta of the Mississippi as they are in the hill section lying some 70 miles to the east of the Mississippi River. However, large numbers are found during the latter part July and in August and September, feeding along the mud bars of the river and about the great number of barrow pits left from levee construction, where they feed along with the herons, wood ibises, egrets, and buzzards on the dead and dying small fry left as the pools dry up. They are destructive to other birds' nests, especially kilideers and terns, where they nest along the river on sand bars. I have seen the crow destroying the nests of terns, as described in a short article in The Qologist for February 1939, page 24"
Albert J. Kirn tells me that in Texas he has seen crows harassed by a marsh hawk and has also seen a crow attacking a marsh hawk. In southern and eastern Texas he finds them fairly common, mostly in river bottom woods, but thinks that the resident birds do not range very far west in the State.
The measurements of 40 eggs of the southern crow in the United States National Museum average 41.4 by 28.9 millimeters; the eggs showing the four extremes measure 47.3 by 30.2, 42.9 by 31.2, and 35.8 by 20.2 millimeters.
Dr. Walter P. Taylor tells me that he called up a crow that came within 150 feet of him and sat in the top of a tree. To his surprise "it began to sing. One would never suspect that such tender notes could come from the raucous throat of a crow. The notes resemble somewhat the clucking of a rooster when he is calling hens to some dainty morsel he has found. The crow's song is more varied, however; sometimes he adds a high-pitched tone, and then again continues with his clucking and gurgling noises.
The Florida crow is smaller than the eastern crow, except for its bill and feet, which are relatively larger and heavier. It is somewhat larger than the southern crow (paulus), which has a smaller and slenderer bill.
The Florida crow (pascuus) is generally distributed over peninsular Florida, except in the northwestern part, west of the Aucilla River; it apparently intergrades with paulus somewhere in the region of St. Marks. I have met with it in various parts of the State but found it nowhere especially abundant, much less common, in fact, than crows are in many other parts of the United States. We found it most commonly in the flat pine woods, especially about the small cypress swamps, but saw it also in the mixed oak and palmetto hammocks and on the prairies.
Nesting: What few nests we saw were in the thick groves of tall, slender longleaf pines. Arthur H. Howell (1932) says: "The nests are frequently placed in oak trees in the hammocks, sometimes in pine trees near the border of a cypress swamp, or in a lone tree on the prairie, 7 to 40 (rarely 60) feet above the ground. They are composed of oak twigs and Spanish moss, and lined with horse hair, cabbagepalm fiber, and small pieces of bark"
Bendire (1895) says of some nests c.ollected by Dr. Ralph: "Several nests were found by him in tall, slender pine trees in low, flat pine woods, usually bordering on swamps. The nests were located in the tops of trees, on horizontal limbs, and close to the trunk, at distances varying from 45 to 70 feet from the ground. They are usually composed of small sticks, lined first with Spanish moss and then with strips of cypress bark; occasionally a few feathers from the sitting bird, hair from cows' tails, bunches of fine grass, and grass with the rootlets attached entered into the composition of the linings, and in one instance the eggs were laid on about half a pint of fine rotten wood. The nests average in measurement about 24 by 9 inches in outer diameter, the inner cup being about 16 inches in width by 5 inches in depth' [the 9 inches probably refers to the height and not the diameter].
Harold H. Bailey (1925) says that they nest in "almost every kind of tree from mangrove, gumbo limbo, and cabbage palm of southern keys to pine, oak, and hardwood trees" farther north.
Eggs: This crow lays three to six eggs, most commonly four or five, which are indistinguishable, except for a slight average difference in size, from the eggs of other crows. The measurements of 40 eggs in the United States National Museum average 41.1 by 28.7 millimeters; the eggs showing the four extremes measure 45.5 by 20.2, 43.2 by 30.9, 37.7 by 29.0, and 40.6 by 20.2 millimeters.
Food: Mr. Bailey (1925) says: "They have little chance [in southem Florida] to feed on or destroy the farmers' grain, or work in the plowed areas for insect life, but resort to food such as frogs, lizards, small snakes, large grasshoppers, and snails; while during the breeding season the colonies of herons, ibis, anhinga, and other water birds a-e robbed of eggs or even small young. In every part of the country where I have studied them, I have found them very destructive birds as a whole"
Behavior: The habits of the Florida crow are much like those of crows elsewhere, though it seems to be tamer and more sociable, less shy, probably because it does less damage to crops and is not persecuted so much as are the more northern subspecies. D. Mortimer (1890) writes:
It is common to see it feeding about the streets and vacant lots of Sanford, especially when the palmetto fruit is ripe enough to eat. It associates freely with the Boat-tailed and Florida Grackles, and also with the Red-winged Blackbird and the Rice-bird, and I have seen Rocks including all these species enjoying themselves about the town, It always retreats before any small bird that undertakes to chase it, though it does so apparently because it is too indolent to drive off its assailant, and not on account of timidity. Omnivorous in the fullest sense, it is always on the lookout for any edible morsel. I have seen Florida Crows attach themselves to the Osprey as soon as the latter captured a fish, and tag it about as if to secure any scraps that might fall during the meal. The Osprey is disturbed by this intrusion and tries to strike the Crows with its wings if they come too close.
Voice: In addition to the ordinary crow notes, two observers have noted some notes that seem to be peculiar to this subspecies. Mr. Mortimer (1890) says: "The Florida Crow has a peculiar note that I never heard uttered by any crow at the North. It is a loud, rattling sound something like the cjy of the Cuckoo, and puzzled me much as to its source until I detected the bird in the act of producing it." And Mr. Howell (1932) refers to what is perhaps the same note: "It suggested the rattling call of the Sandhill Crane, though not so loud, and resembled, also, the 'churring' note of the Red-bellied Woodpecker"
WESTERN CROW CORVUS BRACHYRHYNCHOS HESPERIS Ridgway HABITS
The western crow is decidedly smaller than the eastern crow, with a relatively smaller and slenderer bill. It is very close to the southern crow (paulus) in size, but it has a longer wing and a slightly smaller bill; furthermore, it is widely separated from it in its breeding range. Its range, as given in the 1931 Check-list, is "western North America, from central British Columbia, southern Saskatchewan, and Montana south to northern Lower California and central New Mexico." It apparently breeds very sparingly, if at all, in the extreme southern portions of its range, where it occurs mainly as a winter visitor. Just where it intergrades with the eastern crow on the north and east does not seem to be definitely established. We listed the birds we found in southwestern Saskatchewan as hesperi,~, and a bird taken at Walsh, in southern Alberta, was referred by Dr. Bishop to this race. Frank L. Farley tells me that the birds around Camrose, central Alberta, are of the eastern race. The western crow is very irregularly distributed throughout its range, being rare or entirely lacking in many regions and exceedingly abundant in others; in the regions where it is abundant it is much more numerous than the eastern crow is anywhere, often nesting in colonies.
Dawson (1923) says: "The crow in California is no such constant factor of bird life as he is in the East. He is, instead, very local and sharply restricted in his distribution, so that to a traveller the appearance of Grows is rather a novelty, something to be jotted down in the field-book; and Crow country can scarcely comprise more than a twentieth part of the total area of the State"
Nesting: About Crane Lake, Saskatchewan, we found a few pairs of crows nesting in the small willows; seven nests were recorded in my notes during the latter half of June, all of which contained young. I found crows nesting at two quite different localities in California. On April 10, 1929, in San Diego County, while exploring a long row of sycamores along the banks of a dry stream, I saw a number of crows' nests and many of the birds. The nests were all well up near the tops of rather large sycamores; many of them were apparently occupied, as the birds were very solicitous; but, as the trees were hard to climb and as I did not flush any birds off any of the nests, I did not disturb them. Again, in Ventura County, on April 27, M. C. Badger and I found crows very common and noisy in a large tract of small cottonwoods and willows along the Santa Clara River; we saw a number of nests, mostly in small live cottonwoods, but some in dead cottonwoods or in willows and 15 to 20 feet from the ground; those that we examined were empty. They did not differ materially from other crows' nests.
It seems to be characteristic of the western crow to build its nest at low elevations, as well as in groups or colonies; small trees or bushes seem to be satisfactory as nesting sites, and nests have been found even on the ground. Major Bendire (1895) says that at Fort Lapwai, Idaho, he "occasionally found them breeding in what might be called small colonies, and this was not due to scarcity of timber for nesting purposes; in fact, I once saw here three occupied nests in a single small birch tree, where a number of good-sized cottonwood trees were to be found close by and equally suitable. * * * Cottonwoods, junipers, and willows are most frequently used. Nests are usually placed at heights varying from 20 to 60 feet; but I have found some barely 6 feet from the ground, and in many localities in the West they are rarely placed over 20 feet up. Here also they are said to occasionally nest on the ground, but I have never observed this personally"
Capt. L. R. Wolfe (1931), however, did find a nest on the ground in Albany County, Wyo., and published a photograph of it. "It was in the short grass, on flat, open prairie. The nest was placed in a depression which at one time might have been the entrance of a badger hole. The depression was such that the rim of the nest was just level with the surface of the ground, and it was well filled with grass, weeds and small pieces of sage and willow. The nest had an outside rim of weeds, sage and willow twigs and a few small sticks and was lined with strips from weeds and with cow's hair. The general construction and bulk of the nest was about the same as any tree nest of the species. A few larger sticks and twigs were scattered around on the ground surrounding the nest. This nest contained seven eggs.
W. E. Griffee writes to me from Oregon that nests he found near Portland were mostly in "trees along the sloughs on the Inverness Golf Course, where the crows, like other birds, are protected." On April 25 and 26, 1940, in Lake County, east of the Cascades, he collected seven sets "from scrubby willow clumps out in the Chewaucan Marsh," and thinks he could have taken 30 or 40 more sets there in those two days, if he had concentrated on them. There must have been a large concentration of breeding crows in that region. A still larger concentration is mentioned by Leon L. Gardner (1926) in Klickitat County, Wash. On Rock Creek, crows were found at their noon siesta, and many old nests were located with an abundance of evidence in feathers and droppings that for miles up and down the creek a vast rookery existed. Although this was in August, when the crows had congregated to feast in the almond and apricot orchards, many of the vast hordes referred to later probably nested in that rookery where the nests were seen.
J. A. Munro has sent me the data for 14 nests, found in the brush along the creek near Okanagan Landing, British Columbia; 10 of these were in willows, and one each in an alder, a blackhaw, and a poplar; the heights from the ground varied from 10 to 20 feet.
Eggs: Five or six eggs form the usual set for the western crow, but four or seven are often laid, and as many as eight or even nine have been recorded. J. G. Suthard tells me that he once found a set of nine eggs, eight intact and one broken. "The ninth egg had been broken and the shell telescoped onto another egg, to which it was firmly attached by the dried yolk and albumen. All the eggs were similar in size and shape." Three other nests in the vicinity were examined, in which the "eggs were definitely different from this set"
The eggs of the western crow are similar to those of the eastern crow, except in average size. The measurements of 40 eggs in the United States National Museum average 41.1 by 28.8 millimeters; the eggs showing the four extremes measure 46.2 by 31.2, 44.7 by 31.5, 35.8 by 26.4, and 37.7 by 24.4 millimeters.
Food: Like other crows, the western subspecies is omnivorous; it probably does some good in the destruction of harmful insects and rodents, and as a scavenger; but in many places it has formed the habit of congregating in enormous numbers to feast on cultivated nuts and fruits, which makes it a serious menace and requires effective control measures to save any of the crops.
Mrs. Wheelock (1904) says that "in California, acorns, beechnuts, berries of various shrubs and trees, seeds and all kinds of fruit, with insects such as locusts, black beetles, crickets, grasshoppers, spiders, cutworms, angleworms, and injurious larvae form a large part of its daily menu. In addition small mammals and snakes, frogs, lizards, snails, crawfish, fish, all kinds of dead flesh, and the eggs or nestlings of other birds are his victims. * * * The fact that all feathered creatures are arrayed against him is proof to me that, from the bird-lover's standpoint, he does more harm than good"
Ralph H. TinIer (1939), in his comparative study of the food of crows and white-necked ravens in Oklahoma, found that the crows were apparently more beneficial in their feeding habits than the ravens since they ate many more insects and weed seeds. His analysis of 14 crow stomachs showed the following proportions: "Beetles, 4.6 percent; grasshoppers, 9.4 percent; mammals, 1.2 percent; grain, sorghums, 24.7 percent; corn, 24.9 percent; melons and citron seeds, 18.9 percent; sunflowers, 16.3 percent"
Some of the items mentioned by Mrs. Wheelock may be placed to the credit of the crow, and probably the large percentages of grain in Mr. TinIer's report may be waste grain and therefore neutral; but there is another side to the picture, which is as black as the crow's plumage. Mrs. Nice (1931) says that "in northern Oklahoma crows have become a serious pest in pecan orchards" and describes their crafty methods of work and the none too effective methods of control. "Vast numbers have been killed in Oklahoma: 10,000 in one week near Chickasha in February, 1926, 11,000 in Payne County during the winter 1927-28, 3692 in two nights by means of dynamite near Vinita in January, 1929, according to the newspapers; but vast numbers remain.
Maj. Leon 1.. Gardner (1926) tells an interesting and most remarkable story of an immense congregation of crows and the devastation that they wrought: "In the region of Goodnoe Hills, Klickitat County, Washington, a very promising enterprise in raising almonds and apricots was developing. It was reported, however, by the farmers of that region that in fall enormous flocks, amounting to 'millions of crows,' came into this region and destroyed practically the entire crop of fruit and nuts, together with considerable acreages of watermelons." When he arrived, about the middle of August, "the almonds were ripening fast and crows had assembled in mass from the surrounding country for the annual feast." He continues:
They were in flocks of hundreds to thousands. The usual formation was in one enormous flock which worked as a unit in some selected orchard with a few outlying and unimportant groups feeding at random from other orchards. When in the air, this large host looked at a distance like a huge cloud of gnats.
It was difficult to estimate the exact numbers hut an approximation could be made with the larger group when they settled to work in an orchard. In a 20-acre almond orchard there were about 1500 trees. To each one of these trees one could count from ten to thirty Crows with an average of fifteen to the tree. The flock on our arrival numbered perhaps 15,000 which, in a short time, nearly doubled in size until we estimated fully 30,000 members in the various groups. *** With regard to the almond damage there was no argument. The destruction of an $800 crop was complete in two days after which the Crows moved on to a new orchard. * * *
It was the practice of the Crows, after a hot afternoon's work, to spare themselves the trouble of flying any considerable distance to water by feeding on watermelons. They were never seen to attack melons in the morning but always after a dry day's work. Furthermore green melons were sought and eaten as well as ripe ones indicating it was the moisture they were seeking. In any event the damage amounted to practically 100% of the crop, no melon being spared unless it happened to be concealed in the vines.
Various methods of control or protection of the crops were tried, but with indifferent success. Shooting served only to drive the crows from one orchard to another, and they paid no attention to scarecrows or to belling or stringing the trees. Poisoned carcasses of rabbits were scattered about, but after a few crows had been poisoned the others soon learned to avoid these baits. Poisoned watermelons proved more effective in protecting this crop, for, after a few crows had been killed, no further visits were made to the melon patches. Almonds, slit open, poisoned, and scattered in conspicuous places in the orchards, finally succeeded in driving away the crows, though "the actual number of crows poisoned was extremely small not exceeding 1% of the flock"
He says in conclusion: "The use of poisoned almonds, when properly conducted, proved successful in protecting the crops but demonstrated anew the exceptional sagacity of this bird. The first reaction was one of extreme panic at some of their number being fatally affected by their chief article of diet. This was manifested by tumultuous clamoring and confusion of the flock while sudden sallys and forays were made into distant parts of the Hills only to be met by the same fatal consequences. The flock then rapidly reacted to the changed environment by abandoning attempts at feeding from the almonds and indeed, by departing from the entire region"
There is another score against the crows of western North America, the destruction of the eggs of waterfowl in the great breeding grounds of ducks in the Middle West. We noticed that the nests of crows that we saw in Saskatchewan were largely congregated around the shores of the lakes and sloughs where ducks were breeding. On one small island in Crane Lake we counted 61 ducks' nests in a few hours' search; the following year this island was practically deserted by the ducks; we charged the damage largely to a coyote and a family of minks, but very likely the crows found here an abundant food supply.
Frank L. Farley writes to me that crows have so increased in central Alberta as to become a serious menace to waterfowl. He (1932) writes:
It is significant that as the crows gained in numbers there was a corresponding decrease in the number of ducks, particularly of the marsh-nesting species. In the choice of nesting sites it was noted that the crows favored wooded areas adjacent to lakes and marshlands where ducks nested, this no doubt for the purpose of being close to a rich food supply during the nesting season. Mr. Francois Adam, a former prominent farmer of the Edberg district, and on whose farm are extensive marshes, told the writer of the discovcry of twenty-two ducks' nests on his place one Sunday in May. The following Sunday, being suspicious all was not well with the nesting ducks, he again visited the marsh and was sirprised to find every nest empty, and many crows busily engaged in every part of the marsh, searching for nests that had been overlooked. He stated that there were a dozen crows~ nests in the willows surrounding the lake, and others nearby in scattered clumps on the prairie. It is evident that in such places ducks could not carry on nesting operations successfully.
Eastern crows, which are usually not too abundant anywhere, may not do enough damage to offset the good that they do, making their economic status at least neutral. But the above samples, of which there are probably plenty more, show what damage they can do when concentrated in large numbers.
The western crow, also, has its good traits. S. F. Rathbun writes to me from Seattle: "In the cultivated and more or less open sections lying along the eastern side of the Sound, on occasions early in spring, I have seen numbers of western crows on their northward movement. Wherever the locality had freshly plowed fields, hundreds of crows were on the ground, gleaning every kind of animal food exposed by the plow. The feeding birds never were disturbed by the farmer, who usually regarded them with favor because of the good work the crows were doing.
"One food item, of which this crow is fond, is the fruit of the redberried elder, Sambucus callicarpa, a more or less common shrub of the bottomlands of western Washington. When this bush hangs heavy with its brilliantly colored berries, one often finds the crows eating them. While doing this they are noisy, for the birds will tryto alight on the tops of the fruit-laden bushes, and, as these fail to support them, many birds fall fluttering to the ground amid much excitement and commotion. Once I shot a crow when it was feeding on the berries. I found its gullet packed with the fruit and its stomach also; this organ with the digestive tract proved to be so deeply dyed a dark red that it appeared to show that, for some time at least, elderberries had been the chief food of the bird"
Behavior: There is little to be said about the behavior of the western crow, which does not differ materially from that of its eastern relative. It is the same clever, sagacious bird, wary when in danger and tame where it feels secure. Ridgway (1877) saw three individuals at a stage station in Nevada that "walked unconcernedly about the door-yard with the familiarity of tame pigeons, merely hopping to one side when approached too closely." On the other hand, Henshaw (1875), in Arizona, found them "quite numerous, associating freely with, and apparently the boon companions of the ravens. Yet, even here, I found that they had lost little of their traditional shyness, and it was some time ere I procured a specimen. Gun in hand, I found no difficulty in approaching the trees where sat the ravens, looking down upon me with a comical glance of wonder, tinged with a slight suspicion that all was not just as it should be. But the crows had long before taken the alarm, and made themselves scarce, and from some secure perch sent back their warning caws, given, as it appeared to me, with more than the usual earnestness, as though deprecating the stupidity of their big cousins.
Enemies: Probably western crows occasionally attack hawks or owls, just as the eastern birds do; and sometimes the tables are turned. Joseph Mailliard (1908) tells of a pair of Cooper's hawks attacking a flock of crows that were quietly perched in the tops of some dead trees. The hawks did some good team work, one attacking from above and one from below, but the crows were too alert and no serious damage was done before Mr. Mailliard shot both of the hawks.
Fall: Western crows wander about more or less in fall and winter, and there is a limited migration from some parts of the breeding range, a gradual southward drift that extends the range of the subspecies somewhat south of its summer range. There is probably, also, a retreat from some of the higher altitudes down into the valleys and about the ranches in search of food, and perhaps a coastwise trend. Theed Pearse tells me that some cross over from the mainland to Vancouver Island, where they associate with the northwest crow (caurinus). The two can he easily recognized by their voices.
Joseph Mailliard (1927) mentions a migratory movement in Modoc County, Calif.: "In September, 1925, the crows gathered as they had in the previous year. The number seemed toreach the maximum about September 23, when I estimated the size of the band to be in the neighborhood of 1,000 individuals, all feeding in the stubble field back of our quarters. Ten days after this, small numbers were noted moving toward the south, which movement continued daily until comparatively few remained on October 15, when our party left the field"
Winter: Some western crows spend the winter in the northern parts of their range, for J. A. Munro tells me that sometimes large flocks are seen in the vicinity of Okanagan Landing, British Columbia, in winter. "They are extremely local in their feeding habits during winter, remaining in the vicinity of slaughterhouses, or other places where food is easily obtainable, and returning to the same roost, often several miles away, every evening"
The winter population of crows in Oklahoma, on which so much destructive bombing has been done, seems to consist largely of crows from farther north.
Kalmbach and Aldous (1940) report that "the banding of 714 Crows in south central Oklahoma during the winter of 1935-36 has yielded, during the three and one-half years following their release, 143 returns, slightly more than 20 percent of the birds banded." They say:
Analysis of these returns shows that, of the 65 Crows recovered during the breeding and rearing season (April 1 to August 31), 49 (75 per cent) were killed in the Prairie Provinces of Canada. The dates and locations of numerous other returns recorded in the states north of Oklahoma indicate that many others of this group of Crows may have been on their way to or from Canadian breeding grounds. During this same period of the year not one of the winter-banded Crows was recovered in Oklahoma, clearly indicating that winter Crow control in Oklahoma can have little or no effect on nesting upland game or insectivorous birds of that state.
Although winter Crow control in Oklahoma is destined to remove some birds that would enter the problem of Crow-waterfowl relationships in the Canadian provinces, the effect of this control is certain to be much 'diluted' if the results are to be judged in a continental perspective. This comes about because only a portion of the Crows in Canada can be classed as duck-egg predators, and because the Crow, in what might be termed destructive abundance, occupies possibly only a sixth of the duck-nesting area of Canada and Alaska.