RED-WINGED BLACKBIRDS. Agelaius phoeniceus (Linnaeus)²³

Field characters.—Somewhat smaller than Robin. Males wholly black, except for red 'epaulet' or shoulder patch on each wing at bend. Females brownish black, with under surface more or less streaked with pinkish buff, feathers of back edged with buff, and a light stripe over eye. Voice: Song of males a throaty tong-leur'-lee; both sexes, adult or young, when excited utter a sharp chack; males whistle and scold when nesting precincts are invaded.

Occurrence.—Common locally below Canadian Zone.²³ Restricted to fresh-water marshes with abundant growths of tules (or willows), or to boggy meadows with thick stands of tall grass. More or less gregarious at all seasons.

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²³Three subspecies of Red-winged Blackbirds have been found in the Yosemite section, namely: (1) BI-COLORED RED-WINGED BLACKBIRD (Agelaius phoeniceus californicus Nelson), the race of central California, characterized by absence of any buff border below the red of wing in males, is resident at Snelling and near Lagrange (Lower Sonoran Zone) and a summer visitant on the meadows of Bean and Smith creeks (Transition Zone), east of Coulterville; (2) NEVADA RED-WINGED BLACKBIRD (Agelaius phoeniceus nevadensis Grinnell), of the Great Basin, distinguished by a smaller bill, the presence of a broad huffy edging on red of wing of males and by sharper and more extensive streaking on under surface of females, is a summer visitant to Mono Valley and the vicinity of Walker Lake; (3) KERN RED-WINGED BLACKBIRD (Agelaius phoeniceus aciculatus Mailliard), previously known only from Kern Valley east of Bakersfield, with buff wing bar in male and sharp streaking in female (as in nevadensis), but notable for its long slender bill, was found as a summer visitant to Yosemite Valley in May, 1919, and June, 1920.

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The Red-winged Blackbird is closely associated with the fresh-water marshes which border the lower reaches of the Tuolumne and Merced rivers and with the many small seepage depressions and wet meadows which are found along smaller streams on both sides of the Sierra Nevada. In the dense stands of tules, grasses, and willows which characterize these places the Red-wing finds suitable shelter and in the vicinity forage adequate for its existence through a part or all of the year. In the San Joaquin Valley (Lower Sonoran Zone) the Red-wing is resident throughout the year, but in the western foothills (Upper Sonoran and Transition zones) and in Mono Valley (Transition Zone) east of the mountains, it is but a summer visitant, being forced out by the adverse conditions obtaining through the winter months. At all seasons of the year the Red-wing exhibits gregarious tendencies, but it does so most markedly during winter when compact flocks numbering hundreds and often thousands of individuals roam about on the then wet plains of the San Joaquin Valley. Even during the nesting season, when the members of most sociable species separate, this colonial propensity of the bird is manifested by the propinquity of the nests of different pairs.

The two sexes of the Red-wing Blackbird are strikingly different in coloration, size, and habits. The male is a showy creature, his solidly jet black plumage being set off by a pair of brilliantly red epaulets or shoulder patches (technically the group of feathers known as the lesser wing coverts), one on the bend of each wing. The males are about one-half larger than the females; for example, males of the Nevada race weigh on the average 61 grams (about 2.2 ounces) and females 42 grams (about 1.5 ounces). The female wears a much duller garb, the ground color of her plumage being brownish black, relieved by streaks of lighter color. The nature of this pattern is believed to be correlated with the greater responsibilities and need for protective or concealing coloration on the part of the female while she is incubating the eggs or caring for the young. Young birds in their first full plumage (after the down) resemble the female, but are even more extensively streaked. There is much variation in the appearance of individual female and young birds. This is conditioned by differential wear of the lighter markings which comprise the feather marginings. Attrition of the feathers against one another and against the harsh siliceous blades of the tules or grasses wears these off and tends to give the plumage in general a darker effect. Certain of the males do not acquire the full black plumage until some time after the fall molt, when wear has removed the huffy feather tippings. In some males the epaulets are orange-colored.

The male Red-wing (of whatever subspecies), is readily distinguishable from the males of other species of blackbirds by the red patch on his wing. He entirely lacks the white which is seen on the wing of the Tri-color. Females are distinguished from female Brewer Blackbirds by their streaked pattern. The Brewer is altogether unstreaked.

It is a marked trait of the Red-winged Blackbird to cling to upright stalks. In the tule swamps few or no horizontal perches are available and the long continued addiction to these situations has resulted in the Red-wings using perches of this sort without evident discomfort. In grain fields the Red-wings will cling to stalks barely stout enough to support their weight, and often sway back and forth as the vegetation is blown by the wind or bends under the weight of the birds. Occasionally one particular spot, such as an approach to a nest in a swamp, is used repeatedly, and the stout sharp claws of the feet perforate the tules and leave series of punctures, three in a row, in the tough blades.

The Red-winged Blackbird remains in large flocks until the end of the rainy season. Several flocks of different sizes, including one of at least 400 individuals, were seen from the window of a train between Merced and Snelling on February 26, 1916. On a trip over the same route two months later, on April 26, 1916, we found the Red-wings all in pairs and scattered out, each little swale in the rolling lands being occupied by one or more pairs. The males were then in full courting display. The break-up of the flocks elsewhere in the San Joaquin Valley occurs about the end of March and probably at about the same time in the Yosemite section. Examination of a colony on the Tuolumne River below Lagrange on May 7, 1919, showed that some of the pairs had commenced nesting early in April; and at Snelling, in 1915, mixed flocks comprising males and females were seen on May 29, and, on that date, there were fully fledged young in the tules. These facts would again place the beginning of nesting early in April. But on May 6, 1919, females seen near Lagrange were carrying wet nesting material, and sets of fresh eggs were found on the following day; and at Snelling, in 1915, young just hatched were found on May 29, so that the nesting season of the Bi-colored Red-wing extends at least from early April to the latter part of June. Once the young are grown, the flocking instinct is quickly manifested, and birds of both sexes and all ages band together and roam about in search of food. It seems probable that the representatives of the Bi-colored Red-wing which summer in the foothills drop down to the San Joaquin Valley for the winter season and thus augment the resident population of the plains during the rainy months.

The Nevada Red-winged Blackbirds which occur in Mono Valley are only summer visitants there. On April 26, 1916, when Mr. Dixon arrived at Williams Butte, the male Red-wings were already on hand and had taken their stations in the willow thickets; but no females were observed until May 6, when a flock of about 15 was noted. Most of the male birds taken during that part of the season gave evidence that they were summer residents and ready to mate, while a small minority were transients, en route to more northern localities. The species remains in the region at least until September, for a flock of 25 or so was seen, in a wet meadow near Williams Butte, on September 14, 1915, and lone individuals were noted on September 21 and 23. On the latter date observations were concluded in that locality for the season.

Our field party first noted Red-winged Blackbirds in Yosemite Valley on May 23, 1919, although Miss Margaret W. Wythe (MS) found a few in the willow thickets east of Sentinel bridge in July, 1914. In 1919 at least 8 pairs were apparently settled for nesting in the wet meadows both east and west of Kenneyville. When the Valley was visited in 1920, the Red-wings were twice as numerous. On June 23 a nest was found in an open field situated 6 inches above wet ground in tall saw-grass. It contained 5 small young. Mr. C. W. Michael (MS) reports that small flocks were seen there on various dates up until September 25, and thereafter a solitary Red-wing was observed on October 7, 1920. The birds of Yosemite Valley proved to belong to a race (aciculctus) recently (1915) described from the Kern Valley east of Bakersfield and until now not known to breed in any other locality.

As soon as the flocks begin to break up, the males commence courting and their displays are carried on with little cessation from daylight to dark throughout the nesting season. For this they seek some open situation, never far from the favorite swampy haunts. The male lowers and opens his tail in wide fan shape, spreads and droops his wings until the tips reach to or below his feet, raises his red wing patches outward and forward like a pair of flaming brands, and having swelled out as large as possible, utters his curious throaty song, tong-leur'-lee. Usually this is done while he is perched; less often he mounts into the air and flies slowly over a circling course without departing far from the object of his attention. Interspersed between songs the bird gives other notes, a sharp check or chack, a shrill whistle, or a scolding chatter. He closely guards the immediate nesting precincts and tries to drive away all sorts of intruders, including rival males. He even assists in demonstrations against human invaders. When the female is building the nest he often accompanies her as she goes for nesting material. But this is about the extent of his participation in the family work. Some doubt exists in the minds of naturalists as to the strength of the marital tie among the Red-wings even during the nest-building period. We think it likely that it varies with different pairs. Polygamy may be practiced to some extent.

On May 5, 1919, we established a camp on a gravelly bench beside the Tuolumne River and about two miles southwest of Lagrange. A gold dredger had worked on the river margin some years previously and had left, in place of the fertile tillable plain of rich bottom-land soil, great irregular heaps of rounded boulders of varying size, totally unsuited for any use by humans. But the series of ponds in which the dredger had floated had become converted into tule sloughs and these with the lines of willows and cottonwoods along the adjacent river afforded splendid nesting situations for the Red-winged Blackbirds and other swamp-loving species. Red-wings, both because of their numbers and their incessant activity, were the conspicuous birds, but associated with them were Rails, Least Vireos, Yellow Warblers, Yellowthroats, and Long-tailed Chats—the usual marsh-border assemblage.

The Red-wings in this colony (all of subspecies californicus) were at every stage in the cycle of nesting activities. Nests ready for eggs, fresh eggs, incubated eggs, newly hatched young, and young fully grown were found in different nests, although the account of foraging females given below suggests that most of the young were by this time hatched. The following table summarizes our findings May 6 to 9, 1919.

Nest no. 1.	Four young several days old, eyes not yet opened but some down on heads. Rim of nest 390 mm. above surface of water; nest 110 mm. in outside diameter and 70 mm. high.
Nest no. 2.	Incomplete (presumably deserted); only the outer wall of larger tule material was present. Rim of nest about 400 mm. above water.
Nest no. 3.	Complete and ready for eggs.
Nest no. 4.	Four eggs, heavily incubated. Rim little over 200 mm. from water.
Nest no. 5.	One young bird fully fledged and ready to leave nest.
Nest no. 6.	Four eggs, fresh. Nest about 8 feet above the water in a willow sapling, there being no standing tules in the pond where this nest was located.
Nest no. 7.	Complete and ready for eggs. Location as for no. 6.
Nest no. 8.	Four eggs, fresh. Rim of nest about 300 mm. above water.
Nest no. 9.	Four, young, only a day or two old.
Nest no. 10.	Two eggs, fresh. Rim of nest 310 mm. above water.
Nest no. 11.	Three eggs, one with incubation commenced, the other two half incubated. Rim of nest 445 mm. above water. (See detailed description of this nest below.)

It is likely that some of the nests found completed though empty had been built earlier and were subsequently deserted, for the Red-wing is prone to desert a nest disturbed while in process of construction. The finding of a set of four fresh eggs would show, however, that egg laying had not been entirely ended for the season. Elsewhere, eleven days has been recorded as the time necessary to rear a brood after hatching, and a like period for the incubation of the eggs, so that the nest containing the fledged young bird must have been commenced about April 10 or at least shortly thereafter.

Three or four eggs constitute the usual completed set. The set of two eggs in nest no. 10 was watched for two days, but the number was not increased; it may have been deserted before completion. The nest which held the single nearly fledged young bird was tilted at such an angle as to suggest that the other members of the brood had tumbled into the water and been lost to the bass which lurked in the depths below. A nest (of subspecies californicus) found at Dudley, on Smith Creek, June 19, 1920, contained six eggs, probably a maximum complement. The ground color of the eggs is pale blue, and the scattered markings of dark brown or black, chiefly at the larger end of the egg, consist of dots, spots, streaks, and lines, the latter often running around the pole of the egg.

The Red-wings at Williams Butte and elsewhere near Mono Lake (subspecies nevadensis) lose no time after their spring arrival in commencing their nesting program. The first females were seen on May 6; by May 11 they had paired off with the males, which had arrived earlier. A female taken on May 17 had already begun laying, and on May 26 two nests were found, in one of which the eggs were already partly incubated. But there was considerable variation in the different birds' dates of egg-laying, for on June 22 a nest with one egg and another with 2 eggs was found, while a fully fledged young bird was seen in a neighboring meadow on the same day.

The nests of Red-wings are usually located in tules and at varying distances above the surface of standing water. Two nests found at Lagrange were in willows at the margin of a pond which had no standing tules. At Mono Lake Post Office and other localities in the vicinity of Mono Lake, nests (of subspecies nevadensis) were found in willows, 2 nests being recorded as approximately 5 feet and 10 feet, respectively, above the water; while one was found only 4 inches above the ground in a grass clump in a meadow near Williams Butte.

Nest no. 11 listed above was typical of nests (of subspecies californicus) found in tules. The tips of the supporting tules were 1375 mm. above the water surface, and the nest rim was 445 mm. from the water. The outside diameter of the nest was 110 mm. and the height 110 mm., while the cavity measured 80 mm. in diameter and 70 mm. in depth. The internal diameter was, by comparison, found to be about the length of a female's body. The nest consists of three parts: (1) An outer loosely woven framework of tule leaves fastened to the standing (dead) stems and growing leaves of the tule thicket. The attachment of this outer framework to the tules is very loose, an arrangement which undoubtedly saves some nests from being tipped over when one side is attached to growing tules and the other to a dead stem. (2) Next comes the body of the nest, a firm structure comprising some tules, but chiefly of finer material. This material is worked in while wet, either while it is green or, perhaps, after it has been taken to the stream-side and moistened. Some foxtail grass of the current season and still partly green was incorporated in this layer of one of the nests examined. Some of the material, in the particular nest here described had a coating of green algae suggesting that tules broken down into the water had been used. This middle, wet-woven layer when dried and ready for use is so strong as not to break on moderate pressure with the hands. This is the important structural element in the nest. (3) Finally there is an inner lining, of fine dry grass stems of the previous year's growth. The fibers of this layer are chiefly interwoven with each other, but some extend into the middle layer and hold the two layers together. This inner layer forms the soft lining on which the eggs and later the newly hatched young rest. Later still it gives a holdfast for the sharp claws of the growing young who can thus secure themselves against being tumbled out of the nest during high winds or when the nest is beset by marauders.

From the time that the nests are built until the young are out, the parent birds, both male and female, exhibit much concern when an observer enters or even passes near the colony. They fly up from their perches chack-ing harshly, and scolding and whistling incessantly. If the observer makes a 'screeping' noise with the lips, the males fly up and hover over the nest site, with wings and tail widely spread, as if trying to appear as large and absorbing of attention as possible. The females join these demonstrations at first, but soon retire and leave their otherwise unoccupied mates to continue the protests.

As mentioned above, a single young bird, nearly fledged, was found in one of the nests examined at Lagrange. When an effort was made to lift this bird from the nest he clung tenaciously to it and each of his sharp claws had to be released in turn from the lining material. Later, when released over dry ground, he flew in a direct line toward the nearest patch of green, a willow tree, and the instant he touched the foliage he seized the latter with clenching claws and hung there until disengaged again. The instinctive traits here exhibited must be of positive value to the young Red-wings as safety measures, just after they leave the nest. The face of this young bird was almost bare of feathers. The query arises as to whether this feature in the young Red-wing is adaptive, for better hygiene and sanitation during life in the nest, or whether it is an ancestral trait, showing the relationship of the Red-wing to certain tropical American members of the family. Furthermore, the ear coverts of the young bird had scarcely begun to grow out, and the under wing coverts were likewise undeveloped, although the bird was otherwise nearly fledged. The bird's first need is for feathers to sustain flight; less important or accessory portions of the plumage make their appearance later on.

Observation along the bank of the Tuolumne River below Lagrange on May 7, 1919, disclosed the fact that the Bi-colored Red-winged Black birds in that vicinity were using the river as a fly-way between their nests and some rich forage ground up the river. Thus, in fifteen minutes (2:15 to 2:30 P.M.), 49 birds, all females, were seen to fly up the river past a selected post of observation. Fifteen went singly, and 12 in two's, while there were 2 groups of 4 and one each of 3 and 11. So far as could be seen none going in this direction had anything in the bill. In the same interval of time 38 birds, all females, were counted going down stream. All the latter seen closely were carrying what looked like cutworms. The grouping of these birds was as follows: 25 singles, 5 in groups of 2 each, and one of 3. The fact that fewer were seen going down the river than up was probably accounted for by the fact that some individuals on the return journey cut across a gravelly bench beside the river at this point and went down overland behind a line of willows in a more direct course to their nests; 2 or 3 were glimpsed in such a course. These observations prompted the following conclusions: (1) Somewhere down the river there was a breeding colony of Red-wings; (2) many young in this colony were already hatched and being fed; (3) up-stream was a forage ground, rich enough to warrant a flight of a least a half-mile in each direction; (4) only females forage for food for the young; (5) the flocking tendency manifests itself even in nesting time; (6) there is less tendency to flock on the return journey, when each bird may be assumed to have gathered its quota of food after unequal periods of search and also may be prompted by the then more urgent instinct to return to her brood; (7) males stay continually near the nest, on guard, and do not assist in feeding the young.