[Published in 1958: Smithsonian Institution United States National Museum Bulletin 211: 123-150]
Everyone who notices birds at all knows the red-winged blackbird, or redwing as it is now called; at least they recognize it as a black bird with red on its wings. It is very conspicuous and self-revealing whenever one approaches its haunts. It could hardly be overlooked by even the most casual observer, as the male flies up to announce his presence and display his colors.
The numerous subspecies of the redwing are widely spread all over the continent of North America, except in the arid desert, the higher mountain ranges, the forested and the Arctic regions, wherever they can find suitable marshes in which to breed. The presence of water, or at least its proximity, is essential; and the birds must have certain types of dense vegetation in which to conceal their nests. Marshes or sloughs supporting extensive growths of cattails, bulrushes, sedges, reeds, or tules are their favorite breeding haunts; but where similar types of vegetation, or water-loving bushes or small trees, grow in ponds, around the shores of lakes or along the banks of sluggish streams, the redwings find congenial homes. Wherever such conditions exist throughout this continent, from Central America nearly to the Arctic Circle and from the Atlantic to the Pacific, some form of this species is likely to be found.
Spring.--The redwings are among our earliest spring migrants; the eastern redwing leaves its winter haunts in the southern states before the end of February, reaches New England in March (rarely earlier), and arrives in eastern Canada in April or earlier. In Massachusetts, we look for the first of these harbingers of spring about the second week in March. I wrote in my notes for March 22, 1900: "The first interesting sight that met our eyes, as we walked down the country road, was a detached flock of some ten robins in an old stubble field, the first I had seen that year; it was a welcome sight and their bright red breasts seemed to reflect the warmth of coming spring. A flock of about fifteen redwings, adult males, also arose from the same field and circled about, wheeling with better precision than the best of trained soldiers, their jet black uniforms and scarlet epaulets flashing in the sunlight as they turned. All their movements seemed to be governed by the same impulse, instantly obeyed, as they swooped down upon a small apple tree and alighted with every head pointing toward the wind. Our approach started them off again toward some swampy woods, where they scattered and alighted among the tops of the taller trees."
William Brewster (1906) says: "For several weeks after their first appearance in early spring Redwings are usually found in flocks composed wholly of males. At this season they are seldom seen about their breeding grounds excepting in the early morning and late afternoon. At most other hours of the day they frequent open and often elevated farming country, where they feed chiefly in grain stubbles and weed-grown fields. When disturbed at their repasts they fly to the nearest deciduous trees and immediately after alighting burst into a medley of tumultuous song, inexpressibly wild and pleasing when heard at a distance, but rather overwhelming if the flock be a large one and close at hand."
Chapman (1912) writes attractively of this early spring behavior: "A swiftly moving, compact band of silent birds, passing low through the brown orchard, suddenly wheels, and, alighting among the bare branches, with precision of a trained choir breaks into a wild, tinkling glee. It is quite possible that in the summer this rude chorus might fail to attract enthusiasm, but in the spring it is as welcome and inspiring a promise of the new year as the peeping of frogs or the blooming of the first wild flower."
No better life history of the redwing has ever been published than that written by Arthur A. Allen (1914), based on an exhaustive study of the bird near Ithaca, N.Y. I regret that space will not permit quoting from it as fully as it deserves. His study throws new light on the migratory movements of the species, and suggests that similar studies of other species might be equally enlightening.
As a result of his studies at Ithaca in 1911 and 1910, he divides the migratory waves into seven classes as follows: "Vagrants" arrived from February 25 to March 4; migrant adult males from March 13 to April 21; resident adult males from March 25 to April 10; migrant females and immature males from March 29 to April 24; resident adult females from April 10 to May 1; resident immature males from May 6 to June 1 (1910); and resident immature females from May 10 to June 11 (1910).
The "vagrants" come during the first warm days of spring, although the marshes may still be frozen and the ground still covered with snow; they are supposed to be birds that have wintered not very far south; they do not appear every year, but when they do come they are seen in February; they "are for the most part adult males, but immature males and females may be found among them. They are never in large flocks, and often occur singly. The reproductive organs are very small. . . . They do not frequent the open marsh." Of the arrival of the migrant males, Allen (1914) says:
The first true migrants arriving in the spring are adult males. They appear in flocks, some of which contain a hundred or more birds, and ordinarily are first noted in the marsh, although occasionally seen in tree tops or stubble fields on the uplands. . . . At this season of the year, about 4:30 in the afternoon, let us take a stand at the upper end of the marsh and gaze southward up the Inlet Valley. Presently we discern what appears like a puff of smoke in the distance, drifting in at a considerable height. After a minute or two the smoke is resolved into an aggregation of black specks, and then, as it drops lower and lower, it takes on that irregular form so characteristic of Redwinged Blackbirds. With one last swoop and flutter of wings, they alight on the more prominent of the few scraggly trees at the southern end of the marsh. The migration has begun. For a few moments they shake out their feathers and give vent to their feelings in song. It is but a short time, however, before they start again for the north.
A few birds drop out of the passing flocks and settle down into the marsh for a while, but they soon rise again and join another migrating flock. Flocks coming late in the day fly low and settle for the night in the scanty shelter of the still dormant flags.
Every available perch, not so high as to be conspicuous, is filled with birds down to the water's surface, but were it not for the unspeakable din that arises from the hundred throats, one would scarcely be aware of their presence, so inconspicuous are they against the dark water. If one disturbs them now, there is a rush of wings, but they do not fly far. Raillike they drop back into the marsh a short distance away, and soon resume their indescribable discord. . . .
This period of the migration, which I have termed the arrival of migrant adult males, continues for about two weeks before the resident birds begin to arrive. Each evening there is a well-defined flight into the marsh; each night the birds all roost together; and each morning they all leave for the north. The marsh to them at this period is a shelter for the night only, and the entire day is spent on the uplands.
The birds referred to at the beginning of this chapter by Brewster, Chapman, and the author probably belonged in this class, migrating adult males. Allen (1914) says of the arrival of resident adult males:
The arrival of resident males is first made clear by the actions of the birds themselves. To one unfamiliar with their habits the exact time of arrival is not apparent. Up to this time the birds, for the most part, have kept in more or less well-defined flocks. They have been difficult to approach, the slightest annoyance setting them off. . . . About the end of March, however, certain birds arrive, in whose actions a difference is noticed. They do not fly away at one's approach, or, if frightened, soon return to the same spot. These birds do not associate with the migrating flocks, and they roost alone. If one is enabled to identify an individual bird among them by such characteristics as abnormal feet or the loss of its tail or a primary feather, as has frequently been done in this study, one finds that it never changes its station in the marsh after its arrival. . . . From their first arrival, they assume all rights to the domain in which they have established themselves. Frequently these domains adjoin one another closely, but the birds seldom trespass on one another's rights. When they do so, they seem to recognize the owner's prerogative, so that serious quarrels never ensue.
The resident males have been at their stations only a few days before the first females and immature males appear among the migrating flocks. The last days of March and first of April usually usher them in. Says Allen (1914): "Within a few days, as their numbers increase, small flocks made up entirely of females are observed. It is about this time--the end of the first week in April--that the males begin to show a slight interest in the presence of the females. The former now spend more of their time in the marsh, and resent intrusion into their domains. By this time their reproductive organs show considerable increase in size. Among the migrating birds at this time there is an increasing preponderance of immature males and of females. The latter shun the presence of the males, and whenever they do approach one of the residents, they are immediately driven off."
During the early part of the third week in April, another group arrives, the resident adult females. According to Allen (1914):
The flocks break up and the single birds scatter over the marsh, as did the resident males upon their first arrival. Usually they select a place near some male or group of males. They are much more retiring than the latter, however, and keep mostly near the water's surface, where they are inconspicuous. Whenever they appear on the tops of the cattails, or more especially, when they attempt to fly, they are immediately pursued by one or more of the males. Occasionally a male drives a female in great circles over the marsh and even to a considerable height. Eventually, however, he relinquishes the pursuit and returns to his post. The earlier migrant females, when pursued in this way, immediately leave the marsh. But now, as the male ceases pursuit, the female checks her flight and is soon again at her station near the male. Such maneuvers announce the arrival of the resident females.
About the first week in May, after most of the adult resident birds have begun to nest, the resident immature males begin to appear in numbers. From the second week in May until the last of the month, these flocks continue to arrive. The resident immature females begin to appear with the immature males about the middle of the month. They increase in numbers until the first of June, when they far outnumber the males, and by the second week, when the last migrating birds are recorded, they compose entire flocks. Says Allen (1914), "It is doubtless through some of these birds, at a time when unattached males are difficult to find, that many of the cases of polygamy arise."
Probably the movements of the different classes of migrants are not always as clearly defined as indicated by Allen. Fred M. Packard (1937), while banding redwings at the Austin Ornithological Research Station, at Eastham, Mass., found "unsuspected variation in the behavior of the migrating birds on Cape Cod. Some were apparently true migrants; they were caught but once, and did not repeat. Others lingered for a few days or even a month, repeating during that period, and then left; these also were migrants. A third group stayed in the vicinity from the time of their arrival through the nesting period, as true residents. A large fourth group was composed of individuals that were trapped once or twice on arrival, and then disappeared, exactly like migrants; but these returned after an interval varying form 2 months to 2 weeks, some to nest nearby, others to disappear again." Cape Cod is a long, narrow, curving peninsula pointing northward at its terminus and facing a broad expanse of water. Perhaps the returning birds of the fourth group preferred to turn back, rather than risk the long flight over the water.
Territory.--As indicated above and as noted by all observers, the resident adult male, on his arrival on the breeding grounds or soon after that, "stakes out his claim" to the territory that he has decided to establish and to defend. This claim may be large or small, depending on the size of the marsh and the density of its population; in a large marsh with few redwings nesting in it, the territories may be extensive and well outlined; but in a dense colony, the claims are close together and boundaries are not so well marked. The male stands his ground and defends his territory against intruding male redwings and other trespassing birds; he even drives away female redwings until he is ready to mate.
Ernst Mayr (1941) writes as follows on territorial behavior: "Early in the season, when the weather was still cold and the males had just recently established themselves in their territories, they spent a good deal of time sitting on the top of small bushes or old cattail stalks and calling softly chuck-chuck, particularly when migrating blackbirds flew overhead. They were fluffed up and only the yellow margin of their shield showed. As soon as a singing spell 'overcame' one of the birds his whole attitude changed, and he displayed his red brilliantly--only to fall back into his former lethargic condition when the singing was ended."
Courtship.--While the male redwings are defending their territories and driving away migrating redwings of both sexes, the resident females come, between April 10 and May 1 at Ithaca, according to Allen (1914). They select their own territories, where they plan to build their nests, and these are usually near the station of some established male or group of males. At first the male drives away the newcomer and chases her about over the marsh, but she returns to the spot she has selected. Eventually he is ready to select his mate and may be seen following her about. "He never allows her to escape from his sight, and as she hunts about near the water's surface, he vaunts himself on the nearest cattail. They now may be considered mated."
Probably most redwings are mated in pairs that are true to each other, but this is a matter that is not easily determined in a large colony. Allen (1914) says: "Certain pairs have been observed throughout the season, and found to be mated as steadfastly as are most birds, while in others the tie seems to bind only so long as the male is watchful and able to exert his lordship in driving away other males. A female has been observed to receive one male with spreading wings and quivering feathers, and in the next moment, when this bird had been driven off, to welcome the victor with the same freedom and display."
Females sometimes take a more active part in the courtship performance as observed by Thomas Proctor (1897), who says: "And very amusing indeed it was to watch these comedians in sober brown, but in extemporized ruffs, puffs and puckers, pirouette, bow and posture, and thus quite out-do in airs and graces their black-coated gallants. Their shrill whistle, the meantime continually vied with, or replied to, the hoarse challenges of their admirers, while in noisy chattering, and in teasing notes, they were excessively voluble."
It is generally believed that the redwing is often polygamous, though by no means always so. It is often evident that there are more females and more occupied nests in a marsh than there are males. In one swamp studied by Mayr (1941), he shows 12 nests in his sketch in what he supposed were 6 territories; he was unable to determine the exact number of males, but says that "there were not less than four and not more than six." In another swamp, two males had two females each and another had only one.
Mabel Osgood Wright (1907) writes: "When Redwings live in colonies it is often difficult to estimate the exact relationship between the members, though it is apparent that the sober brown, striped females outnumber the males; but in places where the birds are uncommon and only one or two male birds can be found, it is easily seen that the household of the male consists of from three to five nests each presided over by a watchful female, and when danger arises this feathered Mormon shows equal anxiety for each nest, and circles screaming about the general location."
Numerous banding records have indicated the males far outnumber the females, but this is probably due to the fact that the males enter the traps more readily than the more retiring females, and so are more often recorded. What is probably a more reliable conclusion as to the actual sex ratio was found in the careful studies of J. Fred Williams (1940). He states in his summary:
In a study of nestling Eastern Red-Wings made at Indian Lake, Ohio, from June 18 to July 22 it was found that the young could be sexed by dissection at any time after hatching. With the age of nestlings known to the nearest day it proved possible to distinguish between the sexes by means of weights after the fifth day, and by means of tarsal lengths after the eighth day.
The following sex ratios were found:
Among 119 young, representing the full egg complements of 35 nests, 57 males, 62 females.
Among 94 young which were successfully fledged, 47 males, 47 females.
Among 21 young which died during the nesting period, 9 males, 12 females.
The apparent deviation of the first and third of these ratios from the expected 50:50 could easily be due to random variation in sampling.
To assume that the even 50:50 birth rate, or nearly that, is the rule, does not agree with the well-known fact that the females outnumber the males on the breeding grounds, unless we also assume that the females begin to breed when less than one year old and that the males, at least most of them, do not mate until they are nearly 2 years old. This is true of the yellow-headed blackbird, and probably also of the redwing. With the sexes as unbalanced as they are in the breeding colonies, polygamy is likely to be quite prevalent and promiscuity, or even polyandry, may occur, though the latter is probably rare.
Dr. Charles W. Townsend (1920) gives the following excellent account of the courtship display of the male:
The courtship of the Red-winged Blackbird centers as distinctly about the display of the scarlet epaulettes as does the courtship of the Peacock about the display of his train. The adult male Red-wing when absorbed in feeding is a plain blackbird with a pale yellow stripe on his shoulder or one with a narrow band of red. The color may even be entirely covered up by the prevailing blackness of his costume. When, however, his love passions are excited he spreads his tail, slightly opens his wings, puffs out all his feathers, and sings his 'quonk-quer-ee,' or his still more watery and gurgling song, appropriate to an oozing bog, his 'ogle-oggle-yer.' Now when he puffs out his body feathers he especially puffs out, erects, and otherwise displays to their best advantage the gorgeous scarlet epaulettes. These patches become actually dazzling in their effect as he slowly flies toward the object of his affections, for these beauty spots are most effective when seen from in front.
While admiring the gorgeous display of scarlet and gold set in its framework of glossy black, one is apt to overlook the awkward posture of the bird; standing on some prominent perch, he leans forward, pointing his bill toward his tail beneath the branch, with his back hunched up, as if he were to become violently nauseated, suggesting the ludicrous performance of the cowbird.
Allen (1914) mentions another form of courtship:
In addition to the ordinary display and erection of feathers, a method of soaring is now indulged in. In comparison with that of the Lark, it is rather crude, but undoubtedly it is akin to it. Mounting in a rather irregular spiral, the male bird attains a considerable height, where he hovers, oftentimes for long periods, while his wings barely flutter. Song is not generally indulged in. Eventually, with half-closed wings, the bird drops down in a zigzag course to the marsh. A dozen or more birds may frequently be seen in the air at once, as they perform these evolutions. At this time, also, hovering at a much lower height is frequently indulged in. With a few quick strokes of his wings, the male vaults from his post into the air, and with quivering wings and flaming shoulders, gives vent to his pent-up passion in the "scolding song" described above.
Nesting.--Redwings build their nests in a variety of situations, though usually in a marsh, swamp, or wet meadow, where the nests are placed in cattails (Typhus), dead or living, rushes (Scirpus), sedges (Carex), tussocks of marsh grass, or such water-loving bushes as button bushes (Cephalanthus), alders (Alnus), or willows (Salix). Such associations in shallow ponds, or along the shores of lakes or the banks of sluggish streams, afford suitable nesting sites. Although the birds prefer the vicinity of water, their nests are often found on dry uplands, sometimes at a considerable distance from any water, in fields of tall grass, clover, and daisies, where they must be built close to or even on the ground. Nests in bushes and trees also have been reported by several observers.
A. D. DuBois has sent me the data for 42 nests found in four northern states; 3 of these were in trees or bushes from 8 to 9 feet above the ground; 2 were in clumps of nettles on the margin of a marsh, 2 feet above the dry ground. Of 24 nests reported to me by T. E. McMullen, found in New Jersey, 6 were in bayberry bushes near marshes and among sand dunes near the ocean; one was 9 inches up in a clump of goldenrod in a clover field; and another was 8 inches up in a wild rose bush standing in 8 inches of water. Alexander F. Skutch tells me that he found two nests in upland alfalfa fields near Ithaca, N.Y. "The two were built in exactly similar situations, in the midst of the stalks of an alfalfa plant, with the bottom in each instance three inches above the ground." Witmer Stone (1937) records redwings' nests in privet hedges, marsh elders (Iva frutescens), and one in a small cedar bush, in New Jersey. A. Sidney Hyde (1939) found a nest in a clump of vetch (Vicia) and another in a wild cherry shrub, in northern New York.
William Brewster (1937) says of the nesting habits of redwings at Lake Umbagog, Maine: "Most of them breed on small, floating islands moored not within areas permanently covered by the lake but in bordering marshes which have every appearance of thus belonging to it, whenever completely submerged. The islands float only at such times but they keep ever level with the surface of the water, however quickly it may rise or fall, yet seldom shift otherwise than vertically, being too firmly anchored to solid ground beneath by tough, flexible roots which proceed from living bushes--and perhaps also medium sized trees--that overspread what are essentially buoyant rafts of vegetable matter for the most part long since dead."
Althea R. Sherman (1932) refers thus to tree nesting in Iowa: "It is 25 years since Red-winged Blackbirds began nesting in the tops of our trees, which grow more than half way up the hillside from a brook frequented by others of their species. Since 1907, when four females built nests at heights of 18 to 22 feet from the ground in separate plum trees, there has been great increase in growth of wild currant, wild gooseberry and elderberry bushes in our house yard of about an acre in extent. In these bushes more frequently than in the tops of plum trees do the Red-wings nest."
C. J. Maynard (1883) adds the following: "I have found the nests on an island in the marshes of Essex River, placed on trees twenty feet from the ground! In one case, where the nest was placed on a slender sapling fourteen feet high, that swayed with the slightest breeze, the nest was constructed after the manner of our Baltimore Orioles, prettily woven of the bleached sea-weed called eel-grass. So well constructed was this nest, and so much at variance with the usual style, that had it not been for the female sitting on it, I should have taken it for a nest of I. Baltimore. It was six inches deep."
Dr. George M. Sutton (1942) published a photograph of another pensile nest, found by Malcom W. Rix in Oneida County, N.Y. It was suspended "at the end of a grape-covered willow branch, about three feet above water several feet deep. . . . The inside depth of the nest was only slightly greater than that of the general average of the species, and not comparable to that of a Baltimore Oriole's nest. The color of the nest was distinctly that of a Red-wing's, although the materials apparently were somewhat finer than usual."
W. E. Clyde Todd (1940) mentions two Pennsylvania nests that were more than 30 feet from the ground in willow trees, the highest I have seen recorded. Brewster (1906) reports a nest in a vertical fork of a small apple tree in an orchard not far from a pond. Harold M. Holland (1923) found a redwing's egg and a cowbird's egg in a Bell's vireo's nest; and later an egg of the redwing and two cowbird's eggs, in another Bell's vireo's nest, were so much like the eggs in the other nest that they appeared to have been laid by the same interlopers.
Allen (1914) describes the progress of the nesting at Ithaca:
The first nests built are located in the dead stubs of the cattails that have been burned over during the previous fall. At first they are not sheltered by any vegetation of any kind, for the new growth is barely above the water. . . . As the season advances and the vegetation grows, green stalks are included in the support. At first these are not sufficiently strong to serve alone as a support, and consequently the nests are always attached on one side to the dead stub. . . . This is true of most of the nests constructed in early May, and it generally results in disaster. So firmly are the nests fastened by the strands of milkweed fiber, that the side attached to the green blades is carried upward by their growth, while the other, attached to the dead stubs, remains fixed. As a result, the one side is lifted at the rate of almost an inch a day until the nest is inverted. The birds continue to incubate until the last egg is rolled out. . . . By the end of the third week in May, most of the vegetation in the marsh is sufficiently strong to support a nest, and as a result, nests built at this season are located rather indiscriminately in cattail, sedge, burreed, water horsetail, dock, and arrow arum. By the first of June the cattails and sedges are matured, and have become very dense and harsh. The Redwings now desert them for the softer vegetation, such as the dock and smartweed, which by this time fill most of the small ponds.
The time required for building a complete nest is usually 6 days. Of this time, 3 days are spent on the outer basket and "felting," and 3 days on the lining. Many of the later, more poorly built nests require much less time for construction, some of them being completed in as few as 3 days. . . . The construction of the nest, in all cases observed at Ithaca, has been entirely by the female. The male has never been seen with nesting material in his bill. He is very attentive, however, during the process.
. . .The adult birds commence building again, often before the first young have left the nest. The second nest is located in the immediate vicinity of the first, frequently within a distance of 10 feet. This is true also when the first nest has been robbed or destroyed. One pair, which was experimented upon, built 4 nests within a radius of 25 feet between April 25 and May 18.
Nutall (1832) gives us the most complete description of the nest of the redwing as follows:
Outwardly it is composed of a considerable quantity of the long dry leaves of Sedge-grass (Carex), or other kinds collected in wet situations, and occasionally the slender leaves of the flag (Iris) carried round all the adjoining twigs of the bush by way of support or suspension, and sometimes blended with strips of the lint of the swamp Asclepias, or silk-weed (Asclepias incarnata). The whole of this exterior structure is also twisted in and out, and carried in loops from one side of the nest to the other, pretty much in the manner of the Orioles, but made of less flexible and handsome materials. The large interstices that remain, as well as the bottom, are then filled with rotten wood, marsh-grass roots, fibrous peat, or mud, so as to form, when dry, a stout and substantial, though concealed shell, the whole very well lined with fine dry stalks of grass or with slender rushes (Scirpi). When the nest is in a tussock, it is also tied to the adjoining stalks of herbage; but when on the ground this precaution of fixity is laid aside.
Harold B. Wood sends me the following note: "A dissected nest, which had been built around 18 burreed stalks, was composed of 142 cattail leaves, up to 21 inches in length, and lined with 705 pieces of grasses. It also contained 34 strips of bark of water willow, up to 34 inches in length, which made 273 laps around the reeds, with only one making a complete loop around a stalk. The tensile strength of the matting was tested by placing in the nest increasing weights until a weight of four pounds was held before the nest began to slip down the reeds. Eleven of 42 nests were completed and never used; no nest was ever used for a second brood. Red-wings will not abandon eggs merely because they are discovered, as will robins."
The eggs of the Red-winged Blackbird are mostly ovate in shape; the shell is strong, finely granulated, and moderately glossy. The ground color is usually pale bluish green, and this is occasionally more or less clouded with a pale smoke-gray suffusion. They are spotted, blotched, marbled, and streaked, mostly about the larger end, with different shades of black, brown, drab, and heliotrope purple, presenting great variation in the amount, character, and style of markings. Occasionally an entirely unspotted egg is found.
The average measurement of 380 eggs in the United States National Museum collection is 24.80 by 17.55 millimeters, or about 0.98 by 0.69 inch. The largest egg in the series measures 27.94 by 19.05 millimeters, or 1.10 by 0.75 inches; the smallest, 20.57 by 15.75 millimeters, or 0.81 by 0.62 inch.
Young.--Allen (1914) has this to say about the incubation of the eggs: "During the days when the eggs are being deposited, frequently both birds continue their excursions to the uplands. With the laying of the third egg, incubation begins, and thenceforth both birds remain in the marsh. Incubation, so far as observed, is performed entirely by the female. In one instance the first egg hatched in ten days, and frequently one or more of the eggs requires twelve, but the usual period is eleven days."
Of the development of the young, he writes:
At hatching the young are blind and helpless. The skin is scarlet, with but a scant covering of buffy or grayish down along the principal feather tracts. They are at first exceedingly helpless, scarcely able to raise their heads for food, but they gain strength rapidly after the first feeding. During the first day there is considerable increase in size. On the second day feather sheaths of the primaries and secondaries show distinctly. By the third day these feather sheaths appear distinctly along all of the tracts. On the fourth and fifth days there is a great increase in the size of the body and in the length of the quills. On the sixth the feather sheaths of the wing break open. On the seventh the wing feathers have grown considerably, and those of the other tracts begin to break. On the eighth all of the sheaths have broken, and the wing feathers have attained considerable length. On the ninth the feathers have grown still further, but do not yet cover all of the bare spaces. The young can fly short distances, however, and cannot be kept in the nest if once frightened or removed. If the nest has become polluted, as frequently occurs when it has become greatly compressed by the growing vegetation, they may leave of their own accord on this day. On the tenth the stronger of the young leave and climb to nearby supports. If the nest is approached, all leave, but otherwise the weaker remain until the eleventh day, when all scatter to the vegetation in the immediate vicinity. They all remain in this neighborhood for at least ten days, even after the parents have ceased caring for them and have started a second brood.
He quotes from F. H. Herrick as follows: "In the space of four hours on the first day. . .fifty-four visits were made and the young were fed forty times. The female brooded her young over an hour, fed them twenty-nine times, and cleaned the nest thirteen times. The male made eleven visits, attending to sanitary matters but twice. . . . On the following day. . .in the course of nearly three and one-half hours, 55 visits were made, and the young were fed collectively or singly 43 times. . . . The male bird served food eleven times and attended to sanitary matters once. In the course of forty-two minutes the first young bird to leave the nest was fed eight times, seven times by the mother and once by the father."
Allen continues: "The principal insects eaten are May flies, caddis flies, and lepidopterous larvae. Generally three or four insects are brought each time, and one delivered to each young. This is not always the case, however, for sometimes the entire mass is given to one bird. There seems to be no order in this distribution, the young bird with the longest neck and widest mouth always getting fed first. The food is delivered well down into the throat of the young, and if not immediately swallowed is removed and given to another."
Ira N. Gabrielson (1914) listed the following items given to a brood of young redwings during 51 feedings: 12 unidentified items, 11 wireworms, 1 cricket, 3 beetles, 2 May flies, 3 other flies, 4 green worms, 20 grasshoppers, 3 moths, 1 spider, 4 tomato worms, and 1 measuring worm.
Wood says in his notes: "Of the 37 nests which were followed through the season, 16 had successful broods; 23 contained 73 eggs, of which 53 hatched (72 percent). From these 73 eggs only 35 full-grown young birds left the nests, a productivity of 48 percent. Two out of 94 eggs were infertile." In his published paper (1938), he writes: "The ability of a nestling redwing to take care of himself was tested. A nestling less than two or three days old would be apt to drown if it should tumble out of the nest. As they grow older they become more able to save themselves. Placed in water, the half-grown nestling will float and can swim, but in a very excited manner. They will swim to the reeds and hold on, calling for their parents. When well covered with feathers, but yet a few days before being ready to vacate the nest, they readily swim, but excitedly, and can climb up the cattails to the nest. They are not combative and cannot protect themselves against enemies."
Probably two broods are normally raised in a season, and perhaps often three.
Plumages.--The early nestling plumages are described above. Dwight (1900) describes the juvenal plumage of the young male as follows: "Above, including sides of head, wings, tail, and lesser coverts (i.e., the so called 'shoulders') dull brownish black (no red at this stage), the feathers edged with buff, palest and narrowest on primaries, rectrices, head and rump, and richest on scapulars and secondaries. Below pinkish buff, ochraceous on the chin, thickly streaked (except on the chin) with brownish black. Obscure superciliary line ochraceous-buff."
A complete postjuvenal molt, beginning in August, the time varying for the earlier and later broods, produces the first winter plumage of the male, in which the "entire plumage, including wings and tail," is "greenish black much veiled with buffy and ferruginous edgings, palest below and faint or absent on primaries and rectrices. Lesser wing coverts ('shoulders') dull orpiment-orange, each feather with subterminal bars or spots of black. Median coverts rich ochraceous buff usually mottled with black subterminal areas chiefly on the inner webs, the shafts usually black."
The first nuptial plumage is "acquired by wear, which is considerable, birds becoming a dull brownish black by loss of the feather edgings and by fading. The mottled 'shoulder patches' are characteristic of young birds, the amount of orange varying greatly. The wings and tail show marked wear."
A complete postnuptial molt occurs in August, at which young and old become practically indistinguishable. Dwight describes this adult winter plumage of the male as "lustrous greenish black, feathers of head and back, greater wing coverts and tertiaries edged more or less (according to the individual) with buff and ferruginous brown. Below, the edgings are paler or absent. The bright scarlet-vermilion 'shoulders' are acquired together with the rich ochraceous buff median coverts."
The full brilliancy of the spring plumage is produced by wear, the buff and brown edgings disappearing; the wings and tails of the adults show less wear than in the young birds.
Of the plumages of the female, Dwight (1900) writes: "In natal down and juvenal plumage females differ little from males, the juvenal dress averaging browner above with less buff below and the chin narrowly streaked. The first winter plumage is acquired by a complete postjuvenal moult as in the male, from which the female now differs widely, being brown and boldly streaked. The first winter plumage is hardly distinguishable from the adult winter and passes into the first nuptial by wear, which produces a black and white streaked bird, brown above. A pinkish or salmon tinge is often found in females in any of these plumages, especially about the chin and head, and an orange or crimson tinge may show on the 'shoulders' of the older birds."
Food.--Beal (1900) prepared an extensive report on the food of the redwing, based on an examination of 1,083 stomachs collected during every month in the year from most of its range in the United States and Canada. In spite of the prevailing impression that redwings are very injurious to the farmer's interests, his diagram shows no very decided fondness for grain, as most of the birds' food consisted of weed seeds and insects. Unfortunately, no stomachs were examined from the rice-growing region during sowing and harvesting of this crop, where considerable damage is claimed. "The food of the year was found to consist of 73.4 percent of vegetable matter and 26.6 percent of animal." His table shows the following average percentages for the 12 months: animal food--predaceous beetles 2.5, snout-beetles 4.1, other beetles 3.5, caterpillars 5.9, grasshoppers 4.7, other insects 4.1, spiders and myriapods 1.3, other animal food 0.5, total 26.6 percent; vegetable food--fruit 0.6, corn 4.6, oats 6.3, wheat 2.2, other grain 0.8, weed seeds 54.6, other vegetable food 4.3, total 73.4 percent. The consumption of weed seeds amounts to 97 percent in November.
Another table shows the frequency with which certain vegetable foods were taken. Among the larger items, oats were found in 190 stomachs and corn in 117. Weed seeds of some kind were apparently found in all the stomachs, panic grass in 168, bear grass in 271, ragweed in 189, and smartweed in 200. Small fruits were seldom eaten, blackberries being found in 7 stomachs, blueberries in 2, and gooseberries, strawberries and currants were found in only one stomach each.
Of 84 specimens examined by F. H. King in Wisconsin, 37 had eaten corn and weed seeds, 31 only seeds, 7 only corn, 3 rye, 2 oats, 8 wheat, and 2 tender herbage; five had eaten 7 beetles, four 7 grasshoppers, one a moth, and one a caterpillar; eight had eaten small mollusks. Bendire (1895) includes small mollusks and newts in the food. Forbush (1907) writes: "They forage about the fields and meadows when they first come north in the spring. Later, they follow the plow, picking up grubs, worms, and caterpillars; and should there be an outbreak of cankerworms in the orchard, the Blackbirds will fly at least half a mile to get cankerworms for their young. Wilson estimated that the Red-wings of the United States would in four months destroy sixteen thousand, two hundred million larvae."
During the nesting season, much of the redwings' food is obtained in the marshes, but they resort regularly to the uplands to glean insects, grain, and seeds in the plowed fields, cultivated lands, and recently cut hay fields. They even resort to trees at times. DuBois says in his notes: "From an upstairs window I watched a female redwing, as she searched the foliage of the nearby basswood for the small, smooth, green caterpillars which infest these trees. Her method was similar to that of the vireos, though she lacked some of their skill and grace. She hopped from twig to twig, eating the caterpillars from the leaves; and once she made a little flight to take a caterpillar from the under side of a leaf while hovering in the air. I had seen a female redwing at the same business in this tree before."
Francis H. Allen writes to me: "In October the redwings feed on the seeds of a white ash behind my house. They come there day after day, sometimes for a week at a time. I notice the manner of feeding of a small flock composed of both sexes. After reaching up and picking off a samara, the bird held it against the twig on which it perched and in this way evidently detached the wing, or perhaps shelled the seed. They seemed to be unable to cut off the wing with the bill alone without a solid twig to aid them. My neighbor, Mr. John S. Codman, has seen redwings eating seeds from white pine cones in the tops of the trees, perching on the cones as they picked them out."
Southerners have complained that redwings pull up the long-leaf pine seedlings and eat the seeds. But they are useful in destroying the cotton boll weevil in the south and the alfalfa weevil, two of our most destructive weevils. They also eat the larvae of the gypsy moth and the tent caterpillar.
Economic Status.--On its northern breeding grounds the eastern redwing is almost wholly beneficial, and comparatively few complaints are made of serious damage to crops. Its food while here consists almost entirely of insects, very few of which are useful species, and weed seeds, which form by far the largest proportion of its food. The young are fed almost exclusively on insects. It does some damage to sprouting grain in the spring, and to sweet corn in the summer, while the kernels are soft and milky, by tearing off the husks and ruining the ears for the market. Other grains are also attacked to a limited extent, but much of the grain eaten is waste grain picked up from the ground.
In the Middle West, where the redwings are much more abundant and where the cereal crops are more extensively cultivated, these and other blackbirds, in late summer and fall, swoop down in vast hordes on the grain fields and do an immense amount of damage to the grain both while it is ripening and while it is being harvested. Even there, the redwing has some good points in its favor. Lawrence Bruner (1896) writes from Nebraska: "Even when it visits our corn fields it more than pays for the corn it eats by the destruction of worms that lurk under the husks of a large percent of the ears in every field. Several years ago the beet fields in the vicinity of Grand Island were threatened great injury by a certain caterpillar that had nearly defoliated all the beets growing in many of them. At about this time large flocks of this bird appeared and after a week's sojourn the caterpillar plague had vanished, it having been converted into bird tissue."
In the southern states, it does great damage to the rice crop by pulling up the seedling rice plants in the spring and by eating the soft grain as it ripens. In this respect the redwing is almost as bad as the bobolink. It does some good, however, by destroying the seeds of the so-called "volunteer" rice, which, if allowed to grow, would injure the value of the crop.
S. D. Judd (1901) says that on the fall migration, bobolinks and redwings converge and swarm into the limited area of the rice districts so as to destroy annually $2 million worth of the crop. And B. H. Warren (1890) quotes T. S. Wilkinson as saying: "The rice crop in Louisiana, from the time the rice is in the milk till harvest time and during harvesting, is much damaged by birds, principally the Red-shouldered Blackbird. Shooting is the only remedy thus far resorted to which is at all effective, and it is only partially so. I have known rice crops to be destroyed to the extent of over 50 percent, which is a loss of say $13 per acre. While this is an extreme case, a damage and expense of from $5 to $10 per acre is very common."
Beal (1900) says in conclusion: "In summing up the economic status of the redwing the principal point to attract attention is the small percentage of grain in the year's food, seemingly so much at variance with the complaints of the bird's destructive habits. Judged by the contents of the stomach alone, the redwing is most decidedly a useful bird. The service rendered by the destruction of noxious insects and weed seeds far outweighs the damage due to its consumption of grain. The destruction that it sometimes causes must be attributed entirely to its too great abundance in some localities."
Behavior.--On the ground the redwing walks deliberately, or runs, or hops rapidly when trying to keep up with a feeding flock. In late summer or early fall, one may occasionally see immense flocks of redwings mixed with grackles, cowbirds, and starlings feeding in the open fields. Such flocks sometimes contain hundreds or even thousands of birds. I have seen flocks that covered as much as an acre or more or a broad expanse of meadow or pasture land, densely spread over the ground like a great black mantle. The flock moves along steadily as it feeds, all moving in the same direction; at intervals those in the rear rise, fly over the main flock, and settle in front of the advancing horde, to resume their feeding; this happens again and again, giving the impression of a vast rolling cloud of black birds. When the edge of the field is reached the whole mass rises in a body, to rest in the treetops for a time, or to swoop down into another field.
In the air the flight of the redwing is characteristic; it flies with bursts of rapid wing beats, between which are slight intermittent pauses, producing a somewhat wavy motion. The flocks are in orderly formation, wheeling and turning in unison, but the individual birds in the flock are constantly changing their positions, rising and falling more or less independently. The vast flocks that travel through the southern states in fall and winter are most impressive. Pearson (1925) writes: "At this time they may be seen in flocks numbering tens of thousands, and they present a marvelous spectacle as they fly with all the precision of perfectly trained soldiers. I have seen fully thirty thousand of them while in full flight suddenly turn to the right or the left or at the same instant swoop downward as if they were all driven by common impulse. They perform many wonderful feats of flight when on the wing. Sometimes a long billow of moving birds will pass across the fields, the ends of the flying regiment alternately sinking and rising, or even appearing to tumble about like a sheet of paper in a high wind."
Wilson (1832) says: "Sometimes they appeared driving about like an enormous black cloud carried before the wind, varying its shape every moment; sometimes suddenly rising from the fields around me with a noise like thunder, while the glittering of innumerable wings of the brightest vermillion amid the black cloud they formed, produced on these occasions a very striking and splendid effect."
Redwings are very aggressive in driving away any large bird that approaches their nesting places; crows, hawks, and even ospreys are vigorously attacked and pursued sometimes far beyond the boundaries of the territories; even the bittern is driven to cover in the marsh. Francis Allen tells me that he once saw a redwing "riding on a crow's back for an appreciable length of time."
If a man approaches a nesting colony, even within a hundred feet, the male redwing rises from his lookout perch and flies out to meet him with loud cries of alarm or harsh chacks, hovering over his head and threatening to attack him, but seldom actually striking him. Alexander F. Skutch says in his notes: "As I crossed one large meadow where several redwings apparently had nests, I had an escort of guardian males all the way; for as soon as I passed beyond the bounds of the domain of one of them and he dropped behind, another vigilant bird would take over, hover over me, and shriek down imprecations."
DuBois writes to me of a most pugnacious redwing, saying: "He would hover directly over my head, where I could not see him, and from that advantageous position would strike the top of my head, pecking so hard through a thin summer cap that the blows were quite stinging. After he had struck repeatedly, I hoisted a bamboo staff that I was carrying, directly under him, thus forcing him upward; but he alighted on top of the staff and sat there, temporarily, looking down at me. Three days later, when I had stooped over, near his nest, he struck me on the back and on the arm, and even alighted for an instant on my back. He attacked the camera, also, when I left it standing on its tripod covered with a focussing cloth."
The great fall and winter roosts of redwings and other blackbirds are well know, but few have noted the early summer roosts of the males alone while the females are busy with their nesting. Dr. A. K. Fisher (1896) has told us about this as observed in southern New York in June: "The red-winged blackbird is another species which appears to leave its mate and family to spend the night in company with other males. While watching in this marsh during the early summer evenings the writer has seen flocks composed wholly of males flying in, from an hour before sunset until dusk. Some of these bands contained a hundred or more noisy fellows, while others were made up of only eight or ten individuals. It is probable that all of the males of a given inland marsh band together toward sunset and come to the great rendezvous to spend the night."
Experiments were conducted by Reginald D. Manwell (1941), at Syracuse, N.Y., in April and May, to determine the strength of the homing instinct of the redwing. He released 133 males at distances varying from 2 to 210 miles from the place of capture; of these, 47 birds were recaptured after their return. "The proportion of birds recaught after any given liberation did not exceed 50 percent and was generally not over 33 percent." Some others may have returned, but were not captured. Most of them returned within a week or two, but some did not appear until the following spring.
Voice.--Aretas A. Saunders contributes the following full account of song: "The song of the red-wing, well known to bird lovers as conqueree, is actually much more variable than this simple rendition. It generally consists of from 1 to 6 short notes, followed by a somewhat longer trill. The quality is pleasing, and the presence of prominent liquid and explosive consonant sounds give it a gurgling sound.
"The conqueree song, to my ear more like ko-klareeee, is by far the commonest form, the first note being lowest in pitch, the second medium, and the trill highest. Of 102 records of red-wing songs, 46 have 2 notes followed by a trill, and 19 are as described above. A good many songs of different individuals are apparently just alike, beginning on A'', the second note on C''', and the trill on E'''. On one occasion I listened to 8 birds singing in chorus: 6 of them sang this song, another ended with the trill on D''', and the other began on C''' and ended on G''', but all sang the simple 2 notes and a trill.
"Of my records, 10 have only 1 note before the trill, 29 have 3 notes, 9 have 4 notes, 1 has 5, and 1 has 6; 6 other records do not end in a trill but follow the trill by a low-pitched terminal note ko klareeee tup. While it is common for the trill to be the highest pitch of the song, I have 14 records in which the note before the trill is about 1 tone higher than the trill. A peculiar variation, of which I have 9 records, has the trill made up of notes slow enough to be heard separately and counted. In such cases the number of notes in the trill varies from 5 to 7. Such songs usually have but 1 note before the trill, so that such a song sounds like ka-lililililip.
"Red-wing songs are short, varying from 4/5 to 1 3/5 seconds. The range of pitch, however, is great, from A' to G'''. Individual songs are very variable in range of pitch, from half a tone to 8 1/2 tones. The commonest range, and about the average is 3 1/2 tones; 20 of my records have this range; 10 other records range the 6 tones of a full octave, and 10 more range over an octave. Songs with the greater ranges have 4 to 6 notes before the trill.
"When a male red-wing sings, it commonly spreads the tail, half-spreads the wings, ruffles up the feathers on its back, and lifts the red feathers on its 'shoulders,' so that they flash brilliantly with the coming of the conqueree. At times it sings in flight, and often, when flying from one perch to another, hovers a foot or so above the contemplated perch and sings just before alighting. In the spring migration one may find a flock of male red-wings in the tree tops, nearly every one singing at short intervals, so that the result is a loud continuous chorus. In May, in the nesting season, in a cattail marsh well populated with red-wings, there is a chorus of song just as daylight is beginning. Each male sings his song two or three times a minute, and each female continuously emits a high-pitched, sharp call. I do not remember to have heard this call at any other time.
"The common call of the red-wing, usually written chack, often sounds to me more like tsack. An alarm note, used when one nears the nest, is a downward slurred peeah, and another, less frequently heard, is a mournful sounding downward slide, like peeiiaoh.
"The season of song begins with the first arrival in spring, which in Connecticut is March or sometimes late February. It terminates in late July or early August. The average of 17 years is July 25, the earliest July 16, 1917, in Connecticut, and the latest August 5, 1940, in Cattaraugus County, New York. Ordinarily red-wings do not sing at all in the fall, but once, October 31, 1937, I found a small flock of males, several of them singing."
DuBois writes to me: "On April 28 and 29, 1930, I heard a thrush-like song suggestive of the veery coming from somewhere beyond a house; and on May 2, I definitely saw a female red-wing singing this song at the edge of the marsh by the road." I can find no other mention of a female song.
Witmer Stone (1937) gives his impression of the voices of the pair when their breeding ground is invaded as follows:
As one approaches the nesting site the male launches into the air and begins to call 'sheep; sheep; sheep; sheep,' each call separated from the next by an interval. Then as the excitement increases there is a long drawn 'zeeet' interpolated irregularly thus: 'sheep; sheep; sheep; sheep; zeeet; sheep; sheep; sheep; zeeet; sheep; sheep; zeeet,' etc., the bird all the while poised on rapidly beating wings directly overhead, and now and then swooping down still closer. The female, arising from her perch on a cattail, has a similar note but less harsh than the 'sheep' of the male, and she also utters a much more rapid and differently pitched series of notes; 'chip-chip-chip-chip; chip-chip-chip-chip-chip,' etc., then both birds alight on a bayberry bush and call together, the female seeming to relieve the male entirely from the first part of his cry and to her repeated 'chip-chip-chip-chip,' etc., he contributes only the long drawn 'zeeet' at regular intervals so that the combination is almost like his opening effort.
In recording the vibration frequencies of passerine song, Albert R. Brand (1938) found that the highest note in the song of the eastern redwing had a frequency of 4,375 vibrations per second, the lowest note 1,450, with an approximate mean of 2,925 vibrations per second.
Enemies.--Probably more redwings have been killed by man than by any other one agency, for when they swoop down in clouds on the corn fields, grain fields, and rice plantations they have been slaughtered in multitudes to protect the crops. Wilson (1932) gives the following graphic account of how they used to be killed in great numbers, while roosting at night in the marshes. In some places--
when the reeds become dry, advantage is taken of this circumstance, to destroy these birds, by a party secretly approaching the place, under cover of a dark night, setting fire to the reeds in several places at once, which being soon enveloped in one general flame, the uproar among the Blackbirds becomes universal; and, by the light of the conflagration, they are shot down in vast numbers, while hovering and screaming over the place. Sometimes straw is used for the same purpose, being previously strewed near the reeds and alder bushes, where they are known to roost, which being instantly set on fire, the consternation and havoc is prodigious; and the party return by day to pick up the slaughtered game.
Before it was made illegal to sell game in the market, redwings were killed in large numbers in the fall and sold in markets as "reed-birds"; when fattened on grain or rice, their little bodies served as delicious morsels for the gourmand's table; few could distinguish them from bobolinks.
The high mortality rate in the nestlings has been mentioned above; probably 50 percent of the eggs laid fail to produce young large enough to leave the nest. The large nesting colonies are fruitful hunting grounds for furred and feathered predators. Crows and grackles eat the eggs, and even the small nestlings, if they are left unguarded. Dr. Allen (1914) accuses the long-billed marsh wren as being accountable for the greatest devastation, which is rather strange since they live so close together in the marshes. He says:
While I was standing near a nest containing two eggs, I noticed a peculiarly acting Marsh Wren about 30 feet away. The vivacious notes so characteristic of the species were not uttered. It made its way through the vegetation directly toward the nest until within about 10 feet of me, when it began to circle. After I had retired to a distance of about 15 feet, the Wren went without hesitation straight to the nest, hopped upon the rim, and, bending forward, delivered several sharp blows with its beak upon one of the eggs. It then began to drink the contents much as a bird drinks water. After a few sips, it grasped the eggshell in its beak and flew off into the marsh, where it continued its feast. . . . That cases are not isolated is shown by the fact that of 51 nests of the Redwing observed in a limited area, the eggs of 14 were destroyed in this or in a similar way, and it is not at all uncommon to find one or more of the eggs of a nest with neat, circular holes in one side, such as would be made by the small, sharp beak of a Wren.
J. A. Weber (1912), of Palisades Park, N.J., tells of seeing a bronzed grackle causing a great commotion in a colony of redwings. He shot the grackle and found a young redwing in its bill; the skull of the young bird, which was large enough to have been out of the nest for about a week, had been crushed. An investigation of the nests in the vicinity showed them to contain only one or two young in each, indicating that the grackles may have robbed them. Usually the grackles take only the eggs or the very small nestlings.
The reactions in a redwing colony to the presence of hawks and other large birds show that they are regarded as potential enemies; great horned owls could do considerable damage to the adults and also to the larger young, as could marsh, sharp-shinned, and Cooper's hawks; even the apparently inoffensive bittern might not object to eating a tender nestling. Minks, foxes, and weasels, and in the drier spots squirrels, could easily climb to the nests and destroy the eggs of young. Wood says in his notes that "water snakes, Natrix sipedon, seen in the swamp, gave evidence of having destroyed some nests." The damage done to nests, eggs, and young by predators is, however, not always a total loss to the productive capacity of the colony, for the redwings will continue to build new nests and make repeated attempts to raise their broods until well into midsummer, when their reproductive urge wanes.
Friedmann (1929) calls the redwing "a fairly common but rather local victim" of the cowbird. At Ithaca, Allen (1914) found hundreds of nests but never any cowbirds' eggs. On the other hand, Walter A. Goelitz (1916), of Ravina, Ill., writes: "Until this year I have never found the eggs of this bird in Red-wing nests, but in a little colony of some twenty-five pairs of Red-wing Blackbirds, I destroyed eleven Cowbird eggs on June 17th and six on June 27th of the present season."
Robert H. Wolcott (1899) never saw a cowbird's egg in a redwing's nest during his collecting in Michigan, but found it not unusual in Nebraska. He says: "The owners of the nest, in case eggs of their own have already been deposited, apparently peck holes in all, including that of the intruder, and desert the nest. But in one instance a nest was found where the single, still fresh Cowbird's eggs which it contained had been almost entirely buried beneath a new floor, and above this were four Blackbird's eggs."
Out of hundreds of nests, found at Buckeye Lake, Ohio, by Milton B. Trautman (1940), "a Cowbird's egg was found in each of 4 nests. These nests were isolated. Apparently, it was sometimes possible for a Cowbird to lay its egg in a solitary nest without discovery, whereas if it attempted to lay an egg in a nest in a colony, it was driven away. Once eggs were in the nests the Cowbird was not tolerated about the nesting colonies."
Redwings are afflicted with a number of external and internal parasites; Allen (1914) lists four species of Acarina and three of Mallophaga; and Harold S. Peters (1936) names three species of lice, one fly, three mites, and two ticks that infest the eastern redwing.
In spite of their many enemies, some redwings seem to live for a reasonable number of years. From his study of banding records on Cape Cod, Mass., Packard (1937) has this to say about longevity: "Averages compiled from the 266 returns show that 16 percent of the total number of Red-wings banded survived one year, 7 percent two years, 4 percent three years, 2 percent four years, and 0.3 percent five years after banding." This takes no account of any survivors that did not return to the traps; and the ages of banded birds is not always known. He continues: "The oldest males in the records are two banded as adults in April 1931, and taken yearly through 1936. As it requires at least two years to attain to adult plumage, these birds were hatched in 1929, or earlier, thus being at least seven years old. Several females lived five years after banding." Banding records published by May Thacher Cooke (1937) show that 6 redwings lived for 5 years after banding; 2 for 6 years and 1 for 8 years; only 2 of the 5-year-old birds were banded as young birds, so that some of the others may have been 2 years older than the records indicate.
Field marks.--The male redwing, with his gaudy epaulets, is unmistakable; but the female, with her brown back and streaked breast, is much less conspicuous. At a distance redwings in any plumage can often be recognized by their flight and flock formations, as described above. ***
Fall.--After the young of the second brood are strong on the wing, sometime in July, the females and young gather in flocks and feed on the uplands during the day, returning to the marshes to roost at night. The adult males form separate flocks and follow the same plan. But early in August, all the redwings seem to disappear, during the molting period, and are not much in evidence until the middle of September or later, all in fresh plumage and ready to migrate. Allen (1914) explains this disappearance as follows:
The adult males, which begin molting about two weeks earlier than the females or young, are the first to go, and shortly they are followed by the females and young. To the ordinary observer they have completely disappeared. No longer are they seen leaving the marsh in the morning or returning at evening. Along the ponds, streams, and lake shore there are none to be seen. They are apparently gone from the neighborhood. If at this time, however, one penetrates into the heart of the marsh, where the flags wave four and five feet over his head, he may hear a rush of wings ahead of him as a flock of birds breaks from cover and drops again into the flags a short distance beyond. He may hear this again and again, and yet never see a bird, so impenetrable is the thicket of flags. A few vigorous "squeaks," however, such as frequently draw birds from cover, and the secret is disclosed. A flock of tailless, short-winged birds hover above his head for a moment, and then is off again into the tangle. If specimens are collected, the disappearance of the Red-wings is no longer mysterious. Aside from the loss of the tail, which is obvious, one finds that the outer primary feathers are but just breaking their sheaths. With such handicaps, it is no wonder that the long flights to the uplands are not attempted, and that they seek protection in the effectual shelter of the marsh.
About the middle of September, the males appear again on the uplands, 2 weeks ahead of the females and young. Says Allen (1914):
Well defined migration begins about the middle of October. At that time all loitering ceases, and the evening and morning flights in and about the marsh are very regular, scarcely a bird lingering during the day. Beginning about three-fourths of an hour before, and continuing about half an hour after the sun has disappeared behind the hills, they can be seen in flocks of from ten to a thousand continually dropping into the marsh. . . . The form of the flock is rather irregular, but always with the long axis at right angles to the direction of flight, thus differing from the characteristic form of the flocks of Grackles which sometimes extend for over a mile in length, although only a few rods wide. The maximum flight occurs at sundown. The morning flight is not so regular as that in the evening, and it extends over a shorter period. Beginning a few minutes before sunrise, flocks are continually in sight for about thirty minutes. Their formation is open and they vary in numbers from a few to over ten thousand birds, the largest flocks extending to the east and to the west as far as the eye can see, but generally not more than a hundred birds deep. . . . The method of segregation of these birds in the morning flight is interesting. A single male or a small group of males, finding themselves in a flock of females, drop out of the ranks and await the appearance of a flock of their own sex, or until their own numbers are sufficiently augmented to form a flock of some size, when they are again up and away. . . . The fall migration continues until about the middle of November. The last birds seen are generally scattered flocks of females."
The southward migration from Cape Cod, and perhaps from other localities in southern New England, apparently starts much earlier than from Ithaca, N.Y., as described above, due to different conditions in the marshes. Fred M. Packard (1936) writes: "The swamps of Cape Cod differ considerably from those about Ithaca. Cattails are few at the station, and the marsh plants rarely grow taller than four feet, affording but little shelter. . . . While the marsh studied by Dr. Allen is an ideal place for birds to remain undisturbed during the molting period, the swamps of Cape Cod seem poorly suited for such a purpose." From "the almost complete absence of Red-wings in September and later at the station," and from the dates and localities of recoveries of birds banded at the station, he concludes that they "begin the southward migration in July and August before the summer molt is started, and that they probably complete the molt in swamps after their migration has begun. Unlike the swamps of Cape Cod, many of the marshes on the flight route, such as those found near Newark and Salem, New Jersey, afford suitable protection for molting, comparable to that provided by the marsh at Ithaca."
His map, showing fall and winter recoveries of banded birds, indicates that the flight route from Cape Cod follows along the north shore of Long Island Sound to northern New Jersey, across that state to the Delaware River, avoiding the seacoast of New Jersey, and then along the coastal marshes to South Carolina. All but 1 of his 18 recoveries came from these marshes.
Milton B. Trautman (1940) has this to say about the migration of redwings at Buckeye Lake, Ohio: "During fall the species was more numerous than it was at any other season, and many thousands were present daily. On September 10, 1927, Edward S. Thomas took a picture of a small part of a flying flock. There were more than 400 birds in the picture, and we estimated that there were at least 10,000 in the flock. Undoubtedly, there were days during each fall when 20,000 to 50,000 were present."
Winter.--The winter range of the eastern redwing includes much of its breeding range in the southeastern and southern states. Most of the birds spend the winter south of the Ohio and Delaware rivers, and from northern Florida to northern Louisiana and northeastern Texas. But some few are to be found occasionally in winter considerably north of these limits, even as far north and east as southeastern Massachusetts, locally and chiefly along the coast.
Their winter habits are much like those of the fall months,
when they travel about in large mixed flocks with cowbirds, rusty
blackbirds, grackles, and starlings. Milton P. Skinner (1928) says
that, in North Carolina in winter, they show a tendency to join
with meadowlarks and pipits. He says further: "During the
winter from Christmas until March 1927, there was a flock of 200
Red-winged Blackbirds almost constantly with the Cowbirds about
the Pinehurst stockyards. Although they were usually on the
ground, they often alighted on low oaks, sapling pines and even on
tall gums, clustering close together on the very top in compact
flocks. Occasionally flocks of Red-winged Blackbirds were seen
elsewhere, particularly about old cowpea fields. Early in the
winter, and again after the winter was over, I found these
blackbirds about old cornfields, freshly planted oat fields, and
swampy places, but I did not see them there during the
Red-winged Blackbird* Agelaius phoeniceus [Eastern Redwing]
*Original Source: Bent, Arthur Cleveland. 1958. Smithsonian Institution United States National Museum Bulletin 211: 123-150. United States Government Printing Office