Part 6

His gait is distinctly a walk, his motions gliding and graceful. Upon alighting in the branches, after being flushed from the ground, he assumes a statuesque attitude, like that of a startled Thrush. While singing he takes an easier posture, but rarely moves on his perch. If desirous of changing his position he flies from branch to branch instead of hopping through the twigs in the manner of most Warblers. Under the influence of excitement or jealousy he sometimes jets his tail, droops his wings, and raises the feathers of the crown in a loose crest, but the tail is never jerked like that of a _Geothlypis_, or wagged like that of a _Siurus_. On the contrary, his movements are all deliberate and composed, his disposition sedentary and phlegmatic.

_Voice._--The bird student who hears the song of Swainson's warbler as he sings in his wooded retreat is fortunate, for it is one of the outstanding warbler songs and, once heard, leaves a lasting impression upon the listener. At a distance it bears much resemblance to the songs of the hooded warbler and the Louisiana water-thrush. Close up, however, the appealing quality, lacking in the other two, impresses the listener strongly. The song has, in the majority of individuals, a highly ventriloquial effect, but the writer has listened to birds whose notes did not in the slightest degree possess this quality.

The song varies in length and number of notes but can be separated into two distinct parts; the first few notes are uttered rather slowly, the last ones more rapidly and on a descending scale. The second part closely follows the first, with no apparent separation. Brooks and Legg (1942) write: "It might be translated as _whee, whee, whee, whip-poor-will_, the first two (or three) introductory notes on an even pitch, the last _whee_ a half-tone lower, and the slurred phrase with _will_ separated into two syllables, and accented on the _whip_ and on the _wi_-part of the _will_. The last phrase sounded at times remarkably like one of the songs of the White-eyed Vireo."

When the singer begins his performance, the bill is pointed directly up, and he seems entirely unconscious of anything but his own musical efforts. "During his intervals of silence," says N. C. Brown (1878), "he remains motionless, with plumage ruffled, as if completely lost in musical reverie." Brewster (1885a) adds:

It is very loud, very rich, very beautiful, while it has an indescribably tender quality that thrills the senses after the sound has ceased. * * * Although a rarely fervent and ecstatic songster, our little friend is also a fitful and uncertain one. You may wait for hours near his retreat, even in early morning, or late afternoon, without hearing a note. But when the inspiration comes he floods the woods with music, one song often following another so quickly that there is scarce a pause for breath between. In this manner I have known him to sing for fully twenty minutes, although ordinarily the entire performance occupies less than half that time. Such outbursts may occur at almost any hour, even at noontide, and I have heard them in the gloomiest weather, when the woods were shrouded in mist and rain.

Several times the writer has seen males when the inspiration had not quite come to them; the bird would throw back its head but utter only one or two opening notes of his song.

The call note is a chip, which Brewster calls "a soft _tchip_ indistinguishable from that of _Parula americana_." But Murray (1935) writes that it is "more throaty and full-bodied than that of most Warblers." Brooks and Legg (1942) describe it as "clear, penetrating chirps, having (to our ears) much the same quality as do the chirps of the Mourning Warbler. They are not quite so loud, but have a more ringing quality than those of the Hooded Warbler."

_Field marks._--[AUTHOR'S NOTE: Swainson's warbler is a plainly colored bird, with no conspicuous field marks. It is brownish olive above and whitish below, with no white in either wings or tail; there is a whitish line over the eye and a dusky streak through it; but the bill is long and sharply pointed.]

DISTRIBUTION

_Range._--Southeastern United States to southern Mexico.

_Breeding range._--Until about 1935 Swainson's warbler was considered to be confined in summer to the southern canebrakes and coastal marshes. It is now known to breed =north= to extreme southern Illinois, probably (seen in breeding season to Olive Branch, Duquoin, and Mount Carmel); southeastern Kentucky (Big Black Mountain); central to northern West Virginia (Charleston, Mount Lookout, Sutton, and Buzzard Rocks, Monongalia County); and southeastern Maryland (Pocomoke River Swamp). =East= to eastern Maryland (Pocomoke River Swamp); eastern Virginia (Warwick County and Dismal Swamp); eastern North Carolina (New Bern, Lake Ellis, and Red Springs); eastern South Carolina (Summerton, Charleston, and Yemassee); eastern Georgia (Savannah and Okefinokee Swamp); and northeastern Florida (Jacksonville). =South= to northern Florida (Jacksonville, Oldtown, Whitfield, and Pensacola) and southern Louisiana (Mandeville, New Orleans, and Baton Rouge). =West= to eastern Louisiana (Baton Rouge, Bayou Sara, and Jena); central Arkansas (Camden and Conway); extreme northeastern Oklahoma (Copan); and central Missouri (Concordia).

Within this large breeding area are two almost discontinuous breeding ranges: the coastal and swamp range long considered the only home of the species; and the more recently discovered mountain home along the slopes of the Allegheny Mountains from northern West Virginia nearly to the Georgia line where it has been found to an altitude of nearly 3,000 feet.

_Winter range._--The winter home of the Swainson's warbler is very imperfectly known from a dozen or more specimens, most of which are from Jamaica where it has been listed as a rare winter resident. There are records also from the Swan Islands (March 1); Santa Lucia, Quintana Roo; Pacaytain, Campeche; and the city of Veracruz. Two specimens have been taken near Habana, Cuba; one on September 25, the other in April; and one near Guantánamo on January 18, 1914.

_Migration._--Dates of spring departure are: Jamaica, April 8. Cuba--Habana, April 14.

Early dates of spring arrival are: Florida--St. Petersburg, March 25. Alabama--Autaugaville, April 3. Georgia--Savannah, March 25. South Carolina, April 1. Louisiana--New Orleans, March 30. Mississippi--Biloxi, March 31. Tennessee--Memphis, April 20. Texas--Point Bolivar, April 17.

Late dates of fall departure are: Texas--Kemah, September 27. Tennessee--Sulphur Springs, September 9. Mississippi--Gulfport, October 6. South Carolina--Charleston, October 10. Georgia--Savannah, October 18. Alabama--Greensboro, September 6. Florida--Pensacola, October 2; Sombrero Key (4 struck lighthouse November 10).

Dates of fall arrival are: Tamaulipas--Matamoros, August 29. Jamaica, October 1.

_Casual records._--A specimen was recorded near Corsicana, Tex., on August 24, 1880; another was collected at Kearney, Nebr., on April 9, 1905; and one near Holly, Prowers County, Colo., on May 12, 1913.

_Egg dates._--Florida: 3 records, May 7. Georgia: 35 records, May 4 to July 13; 19 records, May 29 to June 17, indicating the height of the season. South Carolina: 28 records, May 2 to June 30; 14 records. May 12 to June 12 (Harris).

HELMITHEROS VERMIVOROS (Gmelin)

WORM-EATING WARBLER

PLATE 10

HABITS

The breeding range of the worm-eating warbler covers much of the central portion of the United States east of the prairie regions. Its center of abundance seems to be in the vicinity of Pennsylvania, but it breeds less abundantly northward to southern Iowa, New York, and New England and southward to Missouri and to northern Alabama and Georgia, as well as in much of the intervening wooded region, where it is essentially a woodland bird.

The distribution, migration, and habits of this warbler were but poorly understood by the early writers on American birds, and neither Wilson nor Audubon ever saw its nest; the latter's description of the nest, probably from hearsay, is entirely wrong. Frank L. Burns writes to me: "Bartram neglected to list this species, although he had furnished the type to Edwards 35 years earlier, and from the information furnished by the youthful Bartram it doubtless received its name, which is a misnomer perpetuated by Gmelin in his _Motacilla vermivora."_ Mr. Burns says further on in his notes: "I searched for 10 seasons before I found my first nest, and oddly enough it was through the parent bird carrying a 'worm' to its young; nevertheless I have since thought that a more fitting name for the species would have been hillside or laurel warbler."

Hillside warbler would not be a bad name for this bird, which shows a decided preference for wooded hillsides covered with medium-sized deciduous trees and an undergrowth of saplings and small shrubbery. Often a running stream with numerous swampy places, overgrown with brier tangles and alders, bounds the base of the hill as an additional attraction. It is seldom seen outside of its favorite woods and returns year after year to the same chosen haunts.

W. E. Clyde Todd (1940) says that in western Pennsylvania "wooded slopes are its chosen abodes, the shadier and cooler the better. * * * Deep ravines, down which trickle little streams, and the slopes of which support good stands of deciduous trees, with plenty of shrubbery and bushes for cover, are favorite resorts." In Ritchie County, W. Va., William Brewster (1875) found it "most partial to the retired thickets in the woods along water courses, and seldom or never found in the high open groves."

_Spring._--The northward movement of the worm-eating warbler evidently begins in March, as the earliest arrivals from the Bahamas, the West Indies, and Cuba reach southern Florida during the first week in April. From its main winter resorts in Central America the flight seems to be partially across the Gulf of Mexico. Professor Cooke (1904) says in part: "The time of arrival on the coasts of Louisiana and Texas is about the same as in southern Florida. * * * Houston is the southernmost point in Texas from which it has been recorded to date, and Alta Mira is the northernmost point of record in Mexico. Since the species is apparently not common west of Louisiana or north of Vera Cruz, it is probable that the principal line of migration is from Yucatan and the coast immediately west of Yucatan directly north to the northern coast of the Gulf of Mexico." According to Williams (1945) the species is common on the coast of Texas in spring, and it probably migrates along the coast. Thence the migration proceeds northward through the Mississippi Valley and through the Atlantic Coast States east of the Alleghenies, the warblers reaching the more northern breeding grounds by the middle of May, where nesting activities begin as soon as mates have been selected.

_Nesting._--Evidently Thomas H. Jackson, of West Chester, Pa., was the first to report the discovery of the nest of the worm-eating warbler; he published an account of it in the American Naturalist for December 1869, from which Baird, Brewer, and Ridgway (1874) quote as follows: "On the 6th of June, 1869, I found a nest of this species containing five eggs. It was placed in a hollow on the ground, much like the nests of the Oven-Bird (_Seiurus aurocapillus_), and was well hidden from sight by the dry leaves that lay thickly around. The nest was composed externally of dead leaves, mostly those of the beech, while the interior was prettily lined with the fine, thread-like stalks of the hair-moss (_Polytrichium_). * * * So close did the female sit that I captured her without difficulty by placing my hat over the nest."

This nest was quite characteristic of the species. Mr. Burns writes to me: "The nest, well hidden under a drift of dead forest leaves, never varied in composition in over a hundred examples examined by me, in partly skeletonized leaves and the characteristic reddish-brown lining of the flower stem of the hair moss." Every one of 50 nests found by Mr. Jackson was lined with these flower stems, and out of 34 nests reported by Dr. Samuel S. Dickey (1934) only one failed to contain this material, being lined with "black and gray horsehair." Samuel B. Ladd (1887) says that "sometimes fine grass and horse-hair are used as part of the lining." Dr. Chapman (1907) writes: "Nests taken by J. N. Clark at Saybrook, Connecticut (C. W. C.) are composed of decayed leaves and lined with stems of maple seeds." And there are probably a few other exceptions to the rule.

Most observers agree that the worm-eating warbler prefers to nest on hillsides, either sloping or steep, but a number of nests have been found on the sides of deep, shady ravines, or on steep banks. Mr. Ladd (1887), however, states: "I have observed that these birds are not confined necessarily to hill-sides, as was heretofore supposed, as I have taken three sets on level ground and in rather open places, with little shade. The experience of Mr. Thomas H. Jackson of this place, who has taken ten nests this year, corroborates this fact."

The nests are generally well concealed under a canopy of dead leaves, drifted by the wind and lodged against a maple, beech, dogwood, or ash sapling, or under hydrangea, laurel, or rhododendron bushes, or under some bunch of weeds or other obstruction. They are sometimes concealed under the roots of a tree or in a cavity in a bank where they are protected somewhat by fallen leaves.

_Eggs._--The number of eggs laid by the worm-eating warbler varies from 3 to 6, but the set usually consists of 4 or 5. The eggs are ovate or short ovate, sometimes rather pointed, and only slightly glossy. The white ground color is speckled and spotted with shades of "russet," "vinaceous russet," and "auburn," intermingled with "light brownish drab" and "light vinaceous-drab." The markings, usually more thickly grouped at the large end, vary considerably, some eggs being boldly marked, while others are almost immaculate, or have just a few pale freckles of "light brownish drab" and "fawn." The measurements of 50 eggs average 17.4 by 13.6 millimeters; the eggs showing the four extremes measure =20.8= by =14.5=, and =15.5= by =12.7= millimeters (Harris).

_Incubation._--Frank L. Burns (1905) writes:

Incubation does not always commence immediately after completion of set, particularly if the season be young. It is probable that the second night witnesses the beginning of that period and, as far as my experience goes, I believe it is performed by the female alone. The male feeds her when covering newly hatched young.

The home-coming of a brooding bird, after a brief airing and feeding, is heralded several hundred yards distant by frequent _chips_ and short flights from branch to branch near the ground, in leisurely fashion and circuitous route, until at length, arriving above the nest, she runs down a sapling and is silent. The bird is a close sitter and if approached from the open front will often allow a few minutes' silent inspection, eye to eye, at arm's length, sometimes not vacating until touched, then she runs off in a sinuous trail, not always feigning lameness before the young are out. When disturbed with young in the nest she will flutter off with open wings and tail, and, failing to lead one off, will return with her mate, who is seldom far off at this period, circling about the nest or intruder, and, if the young are well feathered, she will dash at them, forcing them from the nest and to shelter. Once this brave little bird dashed at me and ran up to my knee, scratching with her sharp little claws at every step. On the return the birds always make the vicinity ring with their protests--a quickly repeated _chip_. The period of incubation in one instance was thirteen days.

_Young._--Mr. Burns continues:

Young fear man soon after their eyes are open, and a menacing finger will cause them to scamper out and away, repeated replacing in the nest proving of no avail after they became panic-stricken. At three days of age they made no outcry but opened their mouths for food, which consisted of a species of white moth, or "miller," and soft white grubs, supplied by either of the parent birds. At that period they were naked except a fluff on head and wing quills, just showing feathers at tips. In the presence of an intruder and absence of the parents, they will sit motionless if not threatened, and, but for the blinking, beady eyes, one might mistake them when well fledged, at very close range, for dead leaves. The head stripes became visible under the nestling down on the seventh day, and they left the nest ten days after leaving the shell, in the one case I have kept record of. The parents keep the young together for several days at least, just how long is impossible to say. One brood is all that is reared in a season, I think.

_Plumages._--Dr. Dwight (1900) calls the natal down "brownish mouse-gray," and describes the juvenal plumage as follows: "Whole body plumage and the wing coverts cinnamon, palest on the abdomen. Wings and tail olive-brown edged with olive-green. Two indistinct lateral crown stripes brownish mouse-gray. A transocular streak dusky." Ridgway's (1902) description is somewhat different: "Head, neck, and under parts buff, the pileum with two broad, but strongly contrasted, lateral stripes of wood brown or isabella color; a postocular streak of the same color; back, scapulars, rump, and upper tail-coverts wood brown or isabella color; wing-coverts light buffy olive, the middle and greater broadly but not sharply tipped with cinnamon-buff; remiges and rectrices grayish olive-green, as in adults." Young birds seem to vary considerably in the color of the upper parts.

A partial postjuvenal molt occurring in late June or early July involves all the contour plumage and the wing coverts but not the rest of the wings or the tail. The young bird in its first winter plumage is practically indistinguishable from the adult at that season, except for the juvenal wings, in which the tertials are lightly tipped with rusty brown.

There is apparently no spring molt, but a complete postnuptial molt occurs in July. Spring birds are slightly paler, grayer and less buffy than in the fall. The sexes are practically alike in all plumages.

_Food._--As I have said, the name worm-eating warbler seems to be somewhat of a misnomer for this bird. Edward H. Forbush (1929) writes: "I find no records of any consumption of earthworms by this species, which although a typical ground warbler spends some of its time hunting among the branches of trees, where it finds span-worms. It also hunts on the ground in damp places frequented by army-worms. Nevertheless these are not worms but caterpillars. Probably, however, in its perambulations and peregrinations upon the surface of the earth the bird now and then does pick up a small earthworm, for earthworms form a staple food for many birds when the ground is moist."

Arthur H. Howell (1924) says: "Little is known of the food of this species, but it seems doubtful whether it lives up to its name of worm-eater.' Two stomachs of this bird from Alabama contained remains of weevils, beetles, bugs, caterpillars, and Hymenoptera." Howell (1932) further reports: "The stomachs of three individuals taken in Florida in April contained small grasshoppers, caterpillars, sawfly larvae, beetles, and spiders. One dragon-fly, one bumblebee, and one 'walking stick' were also included in the contents." Professor Aughey (1878) included the worm-eating warbler among the birds seen catching locusts in Nebraska.

_Behavior._--Brewster (1875) gives the best account of the activities of the worm-eating warbler as follows:

They keep much on the ground, where they _walk_ about rather slowly, searching for their food among the dried leaves. In general appearance they are quite unique, and I rarely failed to identify one with an instant's glance, so very peculiar are all their attitudes and motions. The tail is habitually carried at an elevation considerably above the line of the back, which gives them a smart, jaunty air, and if the dorsal aspect be exposed, in a clear light, the peculiar marking of the crown is quite conspicuous. Seen as they usually are, however, dimly flitting ahead through the gloom and shadow of the thickets, the impression received is that of a dark little bird which vanishes unaccountably before your very eyes, leaving you quite uncertain where to look for it next; indeed, I hardly know a more difficult bird to procure, for the slightest noise sends it darting off through the woods at once. Occasionally you will come upon one winding around the trunk of some small tree exactly in the manner of _Mniotilta varia_, moving out along the branches with nimble motion, peering alternately under the bark on either side, and anon returning to the main stem, perhaps in the next instant to hop back to the ground again. On such occasions they rarely ascend to the height of more than eight or ten feet. The males are very quarrelsome, chasing one another through the woods with loud, sharp chirpings, careering with almost inconceivable velocity up among the tops of the highest oaks, or darting among the thickets with interminable doublings until the pursuer, growing tired of the chase, alights on some low twig or old mossy log, and in token of his victory, utters a warble so feeble that you must be very near to catch it at all, a sound like that produced by striking two pebbles very quickly and gently together, or the song of _Spizella socialis_ heard at a distance, and altogether a very indifferent performance.

_Voice._--Aretas A. Saunders has contributed the following study of the song of this warbler:

The song of the worm-eating warbler is a simple trill, varying from 1-2/5 to 2-1/5 seconds in length. It is usually all on the same pitch, but a few songs rise or fall a half tone, and one record I have rises a full tone and then drops a half tone at the end. The quality is not musical, but rather closely resembles some forms of the chipping sparrow's song. The pitch varies from G sharp´´´ to F sharp´´´´, one tone less than an octave.

The majority of songs are a continuous trill, that is, the notes are too fast to be separated and counted by ear. I have three examples that are broken into short, very rapid notes. Two of these were of 18 notes and one was of 28. Most of the songs vary in loudness, becoming loudest in the middle, or beginning loud and fading away toward the end. One record becomes louder toward the end and ends abruptly.

Francis H. Allen describes in his notes a song "remarkably like that of the chipping sparrow, but more rapid than is usual with that species, I think, and perhaps shorter, though not so short as the chippy's early-morning song. The bill quivers with the song, but does not close between the _chips_. The bird sang constantly as it flitted about, usually 10 or 20 feet from the ground, seeming to prefer dead branches and twigs."