Contributed by Alfred Otto Gross
[Published in 1953: Smithsonian Institution United States National Museum Bulletin 203: 542-565]
While the following account applies primarily to the northern yellowthroat Geothlypsis trichas brachidactyla, for practical reasons it also includes the Maryland yellowthroat Geothlypsis trichas trichas, as the breeding and winter ranges overlap and the literature pertaining to these two forms is so intermixed that they are not easily separated.
The species of Geothlypis respond more readily to the influences of the environment than do other American warblers. As a result 12 subspecies of trichas have been recognized by the 1931 A. 0. U. Check List and subsequent supplements. Of these, 4, trichas, brachidactyla, ignota, and typhicola are in eastern United States and the other 8, occidentalis, campicola, sinuosa, chryseola, scirpicola, arizela, insperata, and modesta are represented in the western part of the country.
The color pattern of the 12 subspecies is similar; and they vary chiefly in minor differences of size and intensity of color. In a number of instances, the great individual variation which characterizes these birds so obscures their subspecific differences that determination of skins is often difficult and positive identification in the field, especially where the ranges overlap, is impossible.
Of the two forms included in this life history, the northern yellowthroat differs from the Maryland yellowthroat, in the male, in its larger size, and by reason of its more greenish upper surface, more whitish frontal band of grays, more extensively yellow posterior parts, and its usually brownish flanks. The female of the northern is similar to the Maryland but is larger, more greenish above, and slightly paler.
The breeding range of the northern yellowthroat extends from Newfoundland, Labrador and Quebec south to New Jersey, northern Pennsylvania and West Virginia, while that of the Maryland extends from southern Pennsylvania south to eastern Texas and northern parts of Georgia and Alabama.
Throughout most of its breeding range the yellowthroat ranks as one of the abundant warblers. Because of the striking and easily recognized plumage of the male, especially the bright yellow throat and contrasting black mask, and its characteristic syllabic and easily memorized song it is one of our best-known birds. The modestly colored female is more difficult to identify, as it may be confused, by the beginner, with other similarly colored warblers. The yellowthroat seldom visits the habitation of man; it prefers wild lands, especially those grown up with briers and low brush. Its favorite nesting haunts are in the tangled vegetation of brooksides or margins of swamp woodlands or among the grass and sedges of the marshes, where it frequently shares the company of such birds as the swamp sparrow and the marsh wrens.
When invading its haunts one is impressed with the vigorous personality of the male. He nervously raises his alarm with a variety of scolding, interrogative chirps and chattering notes and his dark inquisitive eyes sparkle with excitement through the black masks.
He darts with nervous animation from place to place, then disappears in the dense cover only to appear again to denounce the intrusion. He displays many wrenlike characteristics, suggesting to Bartram the name olive-colored wren.
Although seemingly secretive and shy, they are unsuspecting and will often allow an approach to within a few feet of them. When finally convinced that no harm is meant, the male may even pour out his song from an elevated perch above his retreat, well-exposed to view. At times he will sing as he proceeds with his serious search for insects among the grass and shrubs.
Spring.--It is impossible to separate the records on the migration of the subspecies of the yellowthroat occurring on the Atlantic coast. The earliest spring migrants appearing in Florida are said to be the Florida yellowthroat (ignota) whereas the northern (brachidactyla) follows at later dates. The earliest records for North Carolina have been reported as the Maryland yellowthroat (trichas). The matter is further complicated by the fact that southern representatives of the yellowthroat are almost non-migratory, being more or less permanent residents in Florida, whereas the northern yellowthroats which breed as far north as Newfoundland and Labrador pass over southern United States, going directly over the home of their southern relatives to spend the winter in the West Indies.
The earliest dates of its appearance at the Florida lighthouses occur during the first week in March, the numbers increase during April, and it is one of the few warblers that are common migrants in southern Florida during the month of May. The migration of the yellowthroat is thus one of the most extended.
The first yellowthroats arrive in North Carolina during the last week of March, by the middle of April they arrive in New Jersey and Maryland, and late in April they are in New York state. The first arrivals appear in southern New England during the first week of May, and the vanguard of northern yellowthroats can be expected in Maine before the middle of the month, although the bulk of the birds do not appear until a week or so later. They reach the northern limits of their nesting range in Newfoundland by the last week of May.
The subspecies brachidactyla, according to E. C. Oberholser (1938), is a winter resident in Louisiana from October 8 to April 1. Records, presumably of the northern yellowthroat, reach Arkansas and Kentucky about the middle of April, and St. Louis, Mo., a few days later. They arrive in Ohio during the last week of April, Minnesota the first week of May, and by the middle of the month they are on their breeding grounds in North Dakota and Ontario. The progress of the birds on the Atlantic and Mississippi flyways during the spring migration is at approximately the same rate.
Nesting.--Unlike many of our warbiers, the yellowthroat does not nest in the interior of our dense forests and is seldom seen in the upper branches of tall trees, being more or less restricted to low growths of vegetation. However, it is not strictly terrestrial in its habits, as in the ovenbird. It is partial to wet situations but these need not be great in extent. While it may be found on the borders of large marshes and especially on little islands in marshes and swamps it is also met with near springs and small brooks. An extreme-wet situation for a nesting site of the Maryland yellowthroat is described by W. I. Whitehill (1897) as follows: "While collecting in a large slough in Jackson County, Minnesota, on June 9, 1897, amid the green rushes where Long- and Short-billed Marsh Wrens were breeding, I ran across a pair of Yellowthroats. . .in some high rushes in about four feet of water, and upon investigating I found the nest placed almost level with the water in a thick clump of cat-tails, over fifty feet from shore, and right in the midst of a colony of Marsh Wrens."
Often individuals take up their residence in dry upland situations remote from water. They may be found along old fence rows grown up with weeds and tangles of briers and shrubbery, in huckleberry or raspberry or blackberry patches, and along the margins of woodlands and neglected country roadsides. Maurice Brooks (1940) reports that in the central Allegheny Mountain region where the spruces have been cut, the northern yellowthroats have invaded the highest mountains and are now abundant at all altitudes.
I have found it a very common nesting bird on many of the small outer islands off the coast of Maine. Some of these islands are without any source of fresh water and the only apparent attraction is a growth of rank grass and weeds and briers, and the extreme isolation from enemies, that such sites provide. For example, on Outer Green, a tiny islet of a few acres, there is a bit of tall grass and weeds only a few square yards in area, but it is sufficient to serve each year as the home of a pair of northern yellowthroats. On some of the larger islands where there is no fresh water other than rain I have seen as many as four pairs, all of which apparently were nesting.
The nest of the yellowthroat is frequently placed on or a few inches above the ground and is securely lodged in tussocks of grass, reeds, cattails, briers, and sometimes in herbaceous plants such as skunk cabbage and similar vegetation. Quite often the grass in which the nest is built is backed by a shrub or small tree. The nest is always well concealed from view until the grass or shrubs are parted. This in addition to the secretive habits of the birds makes the task of locating the nest most difficult. All I have seen were accidently found by flushing the bird from the nest when scouting through masses of vegetation in search of other birds.
Although the yellowthroat's nest is commonly located on or within a few inches of the ground there are numerous instances in which the nest is secured to tall weed stalks or shrubs well above the ground. I. D. Campbell (1917) describes a nest of the Maryland yellowthroat that he found at Bernardsville, N. J., which was located in an alder, 3 feet above the ground. R. B. Simpson (1920) found a nest in the top of a cluster of laurels that was growing among a growth of hemlock trees. Mr. Simpson states that this nest was more like that of a mourning warbler than of a Maryland yellowthroat. William Brewster (1906) writes: "I have twice found it nesting in ground junipers in perfectly dry upland pastures near Arlington Heights" [Massachusetts]. Others have found nests in a diversity of situations indicating a great deal of individual variation as far as the selection of the nesting site is concerned.
One most unusual situation for a nest is described by A. W. Brockway (1899) of Old Lyme, Conn., as follows:
The locality chosen was near a back entrance to a house situated on the main street of town. A pair of shoes, which were the property of my friend, were placed outside of the door on the under pinning which projected out from the side of the house about two feet. One day he had occasion to wear them and went out and brought them into the house; . . . he discovered something in one of them, and upon examination found it to be a nest. The other shoe contained a few dry grasses and other fine material but for some reason the bird gave up the idea of building in that, and took up housekeeping in shoe No. 2. My friend immediately put the shoes back, thinking that she would return, and upon glancing into the shoe the next day was surprised to see that it contained an egg.
The yellowthroat continued laying until she had deposited five eggs.
P. G. Howes (1919) found a nest of the Maryland yellowthroat near his house in Stamford, Conn., which was effectively guarded by a nest of large hornets. According to Mr. Howes, the birds did not bother the wasps and the wasps respected the birds; a case of symbiosis.
The nests of the yellowthroat are not always isolated from others of their kind. For example Isaac E. Hess (1910) found 17 nests in a half-acre swamp in central Illinois. This small swamp was in an extensively cultivated agricultural area, a region where suitable nesting sites are few in number. This unusual concentration of nesting birds was probably due to necessity rather than to choice.
The nest is a rather large, bulky structure composed of dead grass, weed stems, dead leaves, grape vine bark, dead ferns, etc. all loosely put together. The lining consists of fine grasses, tendrils, delicate fibers of bark, and often a quantity of hair.
The external parts of a nest, located in a meadow, was made up of wide blades of fresh grass lined with moss. Nests in cattail marshes had a foundation of cattail shreds, dried leaves, and grass stems and were lined with fine grasses only.
The nest is cup-shaped but in some instances loosely attached material extends above the main rim and may partially roof over the top of the structure. The average measurements of several typical nests, not including protruding materials, are outside diameter 3 1/4 inches, outside depth 3 1/2 inches, inside diameter of the cup 1 3/4 inches, and its depth 1 1/2 inches.
All nests that I have seen were completed when found, and I have no information as to the time required or the manner in which the nest is built. The female apparently builds the nest, but on one occasion I saw a male bird carrying nesting material and it is probable that he sometimes assists his mate in its construction.
Eggs.--The usual set of the northern yellowthroat is four eggs but complete sets vary from three to five, and as many as six eggs have been reported. The eggs have a ground color of white or creamy white specked chiefly at the larger end with reddish brown, umber and black and with shell markings of stone gray. As in any large series of eggs of a species there is more or less variation from the typical. In some eggs the markings are in a distinct wreath near the larger end, in a few, some of the marks are in the form of small streaks and in still others the marks are faint and much reduced. The average size of two sets of four eggs each is .69 by .52 inch.
[AUTHOR'S NOTE: The measurements of 50 eggs of the northern yellowthroat average 17.5 by 13.3 millimeters; the eggs showing the four extremes measure19.4 by 14.5, and 14.2 by 11.7 millimeters. The measurements of 26 eggs of the Maryland yellowthroat average 16.7 by 13.2 millimeters; the eggs showing the four extremes measure 18.3 by 13.8, 17.5 by 14.0, and 15.4 by 12.1 millimeters.]
Incubation.--The incubation of the eggs requires 12 days and is performed entirely by the female. The male sings throughout the incubation period and is ever alert in defending his territory. He sometimes delivers foods to the female while she is incubating the eggs.
H. Mousley (1917) has found that although the eggs of different individual northern yellowthroats are subject to great variation, the successive sets of any one bird are strikingly alike in shape, size, and markings. Mr. Mousley did not succeed in getting the yellowthroat to lay a third set of eggs after the first two sets had been taken. It is doubtful if the yellowthroat rears more than two broods a year, Although Aretas A. Saunders (1938) believes that some of them do, since he has found the last birds leaving the nest in August. Usually an egg is laid each day until the set is completed but L. H. Porter (1908) reports finding a nest on June 4 in which the set of four eggs was not completed until June 12, a case, according to Porter, in which the deposit of the eggs was greatly prolonged by cold weather.
Unlike many birds, the northern yellowthroat usually leaves the nest unobtrusively when a human intruder comes near and does not betray its location by scolding. In the case of one nest the female sat very closely, and by exercising care I was able to almost touch her before she slipped off, mouse-fashion. She crept silently through the grass to the shelter of the neighboring vegetation and from there watched me intently. On another occasion the reaction of a yellowthroat was very different in respect to a small dog. Both birds made a wild demonstration, calling and scolding loudly and even making passes at the intruder in their efforts to drive him away from the vicinity of the nest.
The birds readily adapt themselves to a blind placed close to the nest, although their suspicions may be aroused at first. A day after the blind is in place they pay little attention to it, and I have had the bird return within 20 minutes after I had entered the structure.
Young.--The young at the time of hatching are nearly naked, having only scant tufts of grayish or mouse-colored down on the crown and dorsal tracts of the body and wings. The eyes are sealed shut. Soon after emerging from the eggs the young are active and open wide their mouths in anticipation of food, which arrives before many minutes have elapsed. In one nest under observation the male delivered the first food in the form of a small, green insect larva. During the first day the male did the major part of the feeding, since the female remained at the nest much of the time to brood the delicate young. She was seen to leave the nest but twice during the first day, probably in search of food. During the first few days the male frequently delivered food to the female at the nest, and she in turn fed it to the young.
By the third day the papillae of the developing feathers of the primaries, secondaries, and tertials, and to a minor degree those of the dorsal tract, have pierced the integument The remainder of the body remains naked except for the persisting tufts of down.
On the fourth day the eyes are open for the first time. The response of the young to the presence of the adults is much more marked than during the first days. Both male and female now share about equally in the arduous task of feeding the young, the food still consisting chiefly of insect larvae or soft-bodied adult insects. In feeding, at one nest I had under observation, the adult birds approached the nest silently, except for low twitters. They sneaked through the grass, selecting definite pathways more or less hidden by the vegetation, thus giving an observer little warning of their approach. The female did all of the brooding, but by the fourth day she spent less time at the nest and took more excursions in search of food.
The young usually emit a fecal sac after they are fed, and this is immediately seized by the parent that chances to be present. During the first few days the fecal sacs are usually eaten, but in later nest life they are more often carried away some distance from the nest and dropped. I have seen the female eagerly keep watch for fully 5 minutes in anticipation of the fecal sac, even stimulating the youngsters with the tip of her bill to make them respond. The birds also removed all other foreign material such as a pellet of gum, small wads of paper, or rolled-up leaves purposely dropped into the nest as an experiment. The eggshells were removed at the time of hatching by the female. Nelle E. Shaver (1918) gives an interesting account of the removal of an addled egg as follows:
The nestlings had crept to one side of the nest to escape the rays of the sun, so that the addled egg remained alone and in plain view. The male Yellow-throat came first to the nest with food. Seeing the addled egg he picked it up between the mandibles and carried it away, without breaking it and with no slips or unsuccessful trials. The bird, carrying the egg, disappeared in the foliage of the trees at a distance of about twenty-five feet from the nest. It is possible that the ridge formed by the shell fragment may have furnished a "grip" by which the egg was firmly held in the mandibles. On the other hand, the mandibles are capable of opening to a surprising degree, and the whole behavior of the bird in this act seemed to proceed without uncertainty or experimentation.
This behavior is probably unusual, as in nests that I have had under observation the infertile egg remained until after the young normally left the nest.
By the fifth day the papillae of the larger feathers are bursting from their tips and this process is considerably advanced by the following day. At times the adult birds peck at the feathers apparently to facilitate the process of unsheathing. On the sixth day the young exhibit evidence of fear when a human observer examines the nest. The food delivered at this time consists of many adult insects such as small moths, spiders, beetles, and grasshoppers. A. C. Redfleld (1911) made a unique observation concerning the order in which the young are fed, as follows: "On one occasion the male fed two of the young. Before he had left the female arrived with an insect. He held his bill toward her as though wishing to take the food from her. Not heeding him she proceeded to feed the young one last favored by the male. Quickly her mate removed the food from the young one's mouth and thrust it into the bill of the third young one, which had received nothing. This would make it appear that the parent birds do actually keep account of which young they have last fed." Mr. Redfield's interpretation may be correct, but it is rare for birds to exhibit such intelligence or to detect the sequence in which the young are fed.
By the eighth day the feathers have proceeded in the unsheathing process to such an extent that the young present a smooth and pleasing contour. A few tufts of down, however, still cling to the ends of some of the contour feathers. Now that the young have a substantial protective covering and have acquired a temperature control, continuous brooding is not essential, but during extreme weather conditions, such as a cold rain or when the nest is exposed to the direct rays of the sun, the female protects the young by shielding them with her half-spread wings.
On the ninth day the young are ready to leave the nest and the least disturbance at the nest is a signal for them to leave. Under normal conditions they remain at the nest until the tenth day.
On June 10, 1945, I flushed a juvenal northern yellowthroat from the tall grass on Cone Island, off the coast of Maine. It flew but a few yards and alighted on a limb of a small dead shrub. The bird then allowed me to approach very near and exhibited not the least fear of my presence or that of the three other observers who stood nearby staring at the little creature. When we continued on our way the bird persisted in following us alighting again and again within a few feet of us. The youngster followed us in this manner for nearly a mile, until finally it joined company with an adult male, possibly its parent, and together they disappeared in the dense vegetation.
A. D. DuBois sends notes of his observations of a northern yellowthroat caring for a young cowbird and of its own young at Lincoln, Illinois, on June 21, 1913: "Found a female yellowthroat caring for a young cowbird which could fly very well and was about twice her own size. The cowbird flew to a bush near me. Its foster mother was nearby with food in her bill but she became agitated at my presence and flitted about, chirping. I suddenly clapped my hand over the young cowbird and thus caught it. The cowbird cried out with its squeaky voice and both male and female yellowthroats were immediately on the scene of the disturbance, fully as much concerned as though this young rascal were their own flesh and blood. The male, particularly, spread and fluttered his wings in a little bush 10 or 15 feet away, exhibiting great excitement, while the female chirped nervously from beneath a bush on the other side. They did not flutter along the ground as many birds do but remained in the weeds and bushes while doing all in their power to attract my attention. Sometimes the male held up his wings in a very pretty fashion. When I released the young cowbird it flew probably 100 feet, the foster mother following after it.
"Later, in the same bushy, weedy pasture, I caught a young yellowthroat, with much difficulty--a pretty little fellow much like the adult female, but with its tail just sprouting. I think this belonged to other parents. They made much less fuss about their own offspring than did the other pair about the young cowbird."
The young are cared for by the adults for an unusually long period after they leave the nest, this being especially true of the second brood of the season, when parent birds may be seen feeding young that are able to fly as well as the adults, and apparently long after the young are capable of caring for themselves; in fact, they have been seen feeding their young up to the time of the fall migration. It is possible that the fall migration starts as a family group.
Plumages.--The juvenal plumage which is acquired by a complete molt of the natal down is described by Dr. Dwight (1900) as follows: "Above, pale olive-brown of variable depth, greenish on the upper tail coverts. Wings olive-brown edged with olive-green, the median and greater coverts faintly tipped with cinnamon. Tail bright olive green. Below, tawny wood-brown, Naples-yellow on the abdomen and olive-yellow on the crissum. Inconspicuous orbital ring pale buff. Bill and feet pinkish buff becoming deep sepia with age."
The following plumages of the Maryland yellowthroat are also described by Dr. Dwight: The first winter plumage is acquired "by a partial postjuvenal molt, beginning about the middle of July, which involves the body plumage and the wing coverts, but not the rest of the wings nor the tail." It is unlike the previous plumage in being "above, deep olive-brown, greener on the upper tail coverts, the crown and forehead tinged with Mars-brown, the forehead frequently with a very few feathers black basally. The wing coverts chiefly olive-green. Below, bright lemon on the chin, throat and crissum, pale straw-yellow on the abdomen, the flanks washed with olive-brown, and a very faint buffy pectoral band." Dr. Dwight notes that "the malar and auricular regions show traces of the black mask varying from a few black feathers to a considerable area always veiled by ashy edgings. The black seldom invades the lores and forehead and never the orbital ring as in the adult. The orbital ring is buffy white."
The first nuptial plumage, he says, is acquired "by a partial prenuptial moult which involves chiefly the forehead, crown, sides of head and chin and not the rest of the plumage. These areas are somewhat worn, as a rule, when the birds reach NewYork in May, but specimens from Jamaica, West Indies, taken December 2nd, January 9th, 22d and 24th and February 4th show actual moult in progress. It is not surprising that the feathers assumed should show considerable wear before May. The black feathers of the 'mask' are acquired."
He says that those of the upper margin of this area are broadly tipped with pearl-gray, which becomes ashy with wear. "This gray band, posteriorly on the crown, has its feathers tipped with Mars-brown and the basal black gradually diminishes more posteriorly as the extent of brown on each feather increases. There is a yellow tinge in some of the feathers. The width of the band varies greatly. The bright yellow chin is also acquired and young birds and old become indistinguishable."
The adult winter plumage is acquired "by a complete post-nuptial moult in July and August. It differs from the first winter dress in possessing a complete black 'mask', which includes the forehead, lores, orbital ring and auriculars, only the forehead and the auriculars being slightly veiled. The 'mask' has a distinct cinereous posterior border veiled on the crown with Vandyke-brown. The yellow below is deeper and the brown wash on the flanks darker in most cases." He reports that 6 specimens out of 22 in this plumage show a few white feathers in the orbital ring, usually confined to the lower eyelid, and 3 out of 23 spring males show the same peculiarity, which seems to be purely individual and possibly peculiar to the younger birds.
The adult nuptial plumage is "acquired by wear," although he thinks there must be only a limited prenuptial molt, for he examined specimens of this species taken every month in the year, but found "only a few young birds showing actual moult in February, March and April." He adds that "the adult nuptial and winter plumages are so extremely similar that wear alone might convert the latter into the former," although even with the large series he examined positive conclusions were not possible.
In the female "the plumages and moults correspond to those of the male. In juvenal plumage the sexes are alike. In first winter plumage the female is much browner, the yellow of the lower surface is wholly replaced by buff, and there is no black about the head. The first nuptial dress is assumed by a limited prenuptial moult (sometimes suppressed) illustrated by a specimen of February 4th. Later plumages differ little, except in yellowness, from the first winter dress and no black is ever assumed about the head."
Albinistic plumages of the yellowthroat have been reported.
Food.--In the case of the yellowthroat, as of other birds which usually inhabit places remote from agricultural areas, no studies based on the stomach contents of a large and representative number of individuals has been made. However, from various field observations and the few stomachs that have been examined we know the yellowthroat is insectivorous in its food-eating habits. In its nesting haunts it has been observed feeding on beetles, grubs, larvae and adults of moths and butterflies, flies, ants, spiders, plant lice, and such insects as leafhoppers and leaf rollers which are abundant among the grass and low-growing herbage that it frequents.
E. H. Forbush (1907) writes: "I watched a Maryland yellowthroat on the low willow sprouts, and saw him pick off fifty-two gipsy moth larvae before flying away." Mr. Forbush concluded in his study of the gipsy moth infestation in Massachusetts that the yellowthroat ranked among the efficient enemies of this pest. At another time Mr. Forbush saw one eat 89 aphids during the course of one minute.
S. A. Forbes (1883), in the examination of three stomachs of the yellowthroat, found four-fifths of the food consisted of canker worms and other undetermined caterpillars, 8 percent consisted of Coleoptera (beetles), gnats amounted to 4 percent, and a small hemipteran (Piesma cinerea) was found. Others have reported yellowthroats in orchards where their chief food seemed to be cankerworms. A. W. Butler (1898) gives the summary of food eaten by 11 specimens of the yellowthroat examined by Prof. F. H. King as follows: 22 case-bearing caterpillars, 5 other larvae, 6 small dragonflies, 3 moths, 3 dipterous insects, 3 small hymenopterous insects, 3 beetles, 3 spiders, 2 small grasshoppers, 1 leafhopper, 2 hemipterous insects, and 2 insect eggs. J. Henderson (1934) quotes Aughey as having reported 8 locusts in the stomach of a single Maryland yellowthroat. C. W. Townsend (1905) found beetles, flies, and small seeds in the stomach of a Maryland yellowthroat he collected at Ipswich, Mass., on December 6, 1903.
Under ordinary conditions the yellowthroat secures its food in an environment remote from agricultural areas, orchards, and gardens; thus it may be thought to be of little economic importance. However, since many destructive insects breed in areas inhabited by these birds, and from there spread to cultivated areas, the yellowthroat can be considered a useful insectivorous bird in its food-eating habits.
Nelle E. Shaver (1918) who made a nest study of the Maryland yellowthroat at the Iowa Lakeside Laboratory on Lake Okoboji has presented detailed and painstaking observations on the food delivered to the young by the adult birds. Miss Shaver summarized the results of 1,694 observations made over the entire nesting period from the time the young hatched until they left the nest. The food delivered was as follows: Unidentified insects 376, moths 347, various larvae 290, spiders 280, mayflies 116, flies 61, unrecognized material 92, caterpillars 20, damselflies 54, beetles 13, chrysalids 13, butterifies 11, seeds 10, caddisflies 3, grasshoppers 6. Miss Shaver states further:
The birds gleaned their food from the ground and the shrubbery close to the ground. The greater amount of the food for the young was such as must have been picked from low bushes around the nest. The small moths which were so numerous in the grass, seemed to afford an unfailing source of supply. . . . The "worms" were the usual miscellaneous assortment, mostly with a greenish color. These were, of course, gleaned from the foliage. The number of spiders taken by these birds was an interesting fact. . . . Sometimes the food morsel was large, and the time required by the young in swallowing made identification possible. At other times the food was small and the feeding process was so rapid that identification was impossible. Much of the small stuff may have consisted of plant lice, etc.
Voice.--The northern yellowthroat may be heard in full song soon after the arrival of the males in spring. Although the song is subject to great individualistic and local variations its characteristic rhythm and the loud, clear, and strongly accented syllables make it distinctive and easily identifiable. But while the song of the yellowthroat lends itself readily to syllabification, few interpreters agree as to what the bird seems to say. Its utterances have been rendered as: I beseech you, I beseech you, I beseech you; witchity, wichity, wichity; witch-a-wee-o, witch-a-wee-o, witch-a-wee-o; peachity, peachity, peachity, etc. Witmer Stone (1937) in his study of the Maryland yellowthroat at Cape May, N. J., emphasizes the idividual variation of the song. He states that no two appeared alike, although each carries a similar phrase that is characteristic and gives to all songs an impression of identity. He offers 13 interpretations of songs he recorded and claims that it was very easy to identify individual birds after their songs were memorized.
Aretas A. Saunders has given us his interpretation of the song as follows: "The song of the yellowthroat consists of 3 or 4 repetitions of a phrase of 2 to 6 notes, with 1 note of the phrase strongly accented. The phrases vary greatly in different songs and individual birds. Some phrases are very common, while others are comparatively rare. 3- or 4-note phrases are much commoner than others. In 106 records of the song of this species, only 1 is of 2-note phrases; 7 are of 5 notes and 3 of 6. The remainder are almost equally divided between 3 and 4. In 5 of these records the phrase is sung only twice; in 67 records three times, in 32 four times, and in 2 five times.
"Probably the commonest phrase is one of three notes, the first highest in pitch, and the last lowest; the first note the one usually accented. This is commonly sung with three full phrases and the first note of a fourth, wit'ato-wit' ato-wit' ato-wit. This is sometimes varied by making it a phrase of four notes, each lower in pitch than the preceding one, making the phrase wee'titato. In the Allegany State Park this is the commonest yellowthroat song. Another common song has the second note highest, and accented, witee'to, and this is varied by two notes on the same pitch before the accented note titiway'to. There are many other variations, but they seem to be less common than these. In all these, however, the song is readily recognized, for it is much more definite and distinctive than most warbler songs.
"The pitch of songs varies from D' ' ' to D' ' ' ', or one octave. Single songs commonly have a range of one and one half to two and one half tones, a very few only one tone, and a few others up to three and one half tones. Songs vary in the rapidity of the phrases and range from 1 2/5 to 2 2/5 seconds in length. Usually about two phrases occupy 1 second of time."
The song of the northern yellowthroat may be heard throughout the nesting season but in the last weeks of July and the first week of August singing is less general and less spirited. I have never heard the song in Maine after the last week of July, but observers in other sections of its range have heard it throughout the month of August and as late as the second week of September, although this late singing is unusual. M. B. Trautman (1940) in his intensive study of the birds of Buckeye Lake, Ohio, writes: "The song period began with the first male arrivals in the spring, reached its height in mid-May, and continued undiminished until late June. There was less singing in early July, and by August it had ceased almost entirely. A few birds continued to sing throughout summer and fall, especially in the early morning. An individual on Lieb's Island sang during late October and until November 2, 1929, the last day on which it was observed." Others have reported individual birds remaining throughout the winter, as far north as Toronto, Canada, that were heard singing their characteristic song in spite of snow and severe weather conditions.
Aretas A. Saunders writes that the northern yellowthroat sings until August 1, an average based on 14 seasons in Allegany State Park. The latest date on which the song was heard was August 8, 1929. Frank L. Burns (1937) states that the approximate duration of the yellowthroat's song is 87 days, extending from May 5 to July 31. Of this time the two nesting cycles were in progress for a period of 77 days. In Arkansas W. J. Baerg (1930) writes that in a 5-year period of study the average singing period extended from April 15 to August 10, or 117 days, about a month longer than the determinations made by Burns in Pennsylvania.
The northern yellowthroat seems to exhibit some ability in imitating the song of other birds. E. M. S. Dale, of London, Ontario, writes to us: "For several days in early May 1933, we heard a chipping sparrow-like song coming from the edge of Spettique's Pond (a mile or two south of London). We were unable to catch a glimpse of the singer until the fifteenth, when we got a good look at it in the very act, and were much surprised to find that it was a northern yellowthroat. We were wondering if it had been listening to swamp sparrows and had copied them. In 1936 a similar case occurred, when we heard what we took to be a short-billed marsh wren singing, only to find that it was the yellowthroat again. I guess we would have all put it down for a wren without thinking a second time, but one of the party took the trouble to look it up. On May 14, 1937 we heard what was without doubt the same bird singing the same wren song from the same location. Here are two instances of a marsh bird whose song imitated very closely the songs of two other marsh birds, the normal songs of the three species being about as unlike as it is possible to get them."
H. Mousley (1919) has determined that the "singing tree," or the place selected by the male for singing, was near the nest; in five nests the distance varied from only 7 to 11 yards. He found this information useful in locating the nests.
H. W. Wright (1912) found that the awakening song of the Maryland yellowthroat at Jefferson Highland, in the White Mountains of New Hampshire, begins on an average at 3:51 a.m. but varied from 3:41 to 3:55 a.m.
The yellowthroat in its haunts is generally well concealed from view, and since it is readily excited and disturbed by our approach, the first indication to us of his presence is a sharp tchch, schick, or chit note which is excitedly uttered as he hops nervously about in the thicket closely scrutinizing our movements to determine whether we are friend or foe. At other times he may be heard to utter a slight chip or tip note.
In addition to the ordinary, or territory, song the yellowthroat has a so-called flight song which is more generally heard late in the season after the birds have begun nesting. The flight song is not so highly developed in the yellowthroat as it is in the true flight singers of the open grass areas, nor is it as spectacular as the performance of two other warblers, the ovenbird and the yellow-breasted chat. The flight song of the yellowthroat is merely an outburst of ecstasy consisting of short, confused, and sputtering notes, but generally including phrases of the common song. It is uttered as it gracefully flies up from the ground to a height of 15 to 20 feet. The song ends while the bird is at its highest point of the flight. He then silently drops to the place from which it started. The flight song is more often heard in the late afternoon or toward evening than it is during the early part of the day.
E. H. Forbush (1929) presents an account of a flight song of the yellowthroat, which was most unusual for the height at which the bird flew during the performance, as follows:
There is an occasional song-flight that goes far beyond the ordinary. I recall but one high-flyer, and probably a high flight is very unusual. One such is described by Miss Florence M. Pease as follows: "On May 14, 1914, I saw a Maryland yellow-throat fly very high, then spiral down and then fly off toward the church, where it was still a good distance from the ground. I was not able to estimate accurately how many feet the bird flew up, but I noted that when it began to spiral down it was far, far above the church steeple. I had always supposed that the flight-song of the Maryland yellow-throat was given from a height of a few feet."
Enemies.--The yellowthroat is subject to the usual enemies of birds that nest near or on the ground. I remember finding a nest of the yellowthroat in a grassy area near a meandering meadow brook in central Illinois where snakes were common. During a second visit to the nest, when the young were 3 days old, I saw a large water moccasin disappearing into the vegetation as I approached. Two of the young were missing and I presume, judging from the behavior of the adults, they were victims of the unwelcome visitor.
A. L. Rand (1943) cites a report from Lake Okeechobee, Fla., in October 1942, where a 3-pound large-mouthed bass was found to have a yellowthroat in its stomach. These fish often feed in shallow water among the water-hyacinth where they could easily capture a bird as they do various insects on or near the surface. Mr. Rand mentions reports of other birds captured by black bass and since yellowthroats are frequent visitors to such situations in quest of insects, it may not be a rare incident. Turtles have been known to capture small birds and may also prove to be an enemy of the yellowthroat.
However, the number of yellowthroats that fall victims to natural enemies are insignificant when compared with the appalling losses suffered by this species during the migration, especially when the great migration waves meet with severe storms and foggy weather. D. E. Culver (1916) gives an account of a large number of birds that were killed on May 21 and 22, 1915, by flying into public buildings and the City Hall in Philadelphia. On May 21 there was a heavy mist or fog prior to the storm, but this was later cleared away by falling rain. Many of the birds became exhausted from continuous fluttering about the lights and later succumbed to exposure, but the death of the majority was caused by dashing into the structures. The Maryland yellowthroat suffered the greatest mortality, Mr. Culver recovering 130 of this species of which three-fourths were females. This sex ratio was due to the lateness of the season, as the males are the first to migrate. Culver also reports that during a migratory wave, October 17 and 18, 1915, the yellowthroat was again killed in large numbers, the total being exceeded only by that of the myrtle warbler.
Robert Overing (1938) on September 12, 1937, between 10:30 p. m. and midnight identified 576 individuals of 24 species which struck the Washington Monument. There was a slight mist enveloping the top of the shaft and the wind velocity was 8 to 10 miles an hour. Mr. Overing identified 189 Maryland yellowthroats and other subspecies of Geothlypis trichas.
W. E. Saunders (1930) writes of the great loss of bird life at Long Point lighthouse, Ontario, during certain nights of September 1929. Out of 2,060 birds killed on September 7, 9, and 24 - 29, 254 of them were Maryland yellowthroats, this being the most frequent victim of the 55 species reported.
A. M. Frazar (1881) reports a great destruction of birds on April 2, 1881, during a sea trip from Texas to Mobile, Ala. Land birds including a great number of Maryland yellowthroats were seen to perish. Even those that came aboard the boat were washed into the sea again.
The yellowthroat is a frequent victim of parasitism by the cowbird. L. E. Hicks (1934) reports that out of 41 nests of the northern yellowthroat he has found 19, or 41 percent, that were parasitized by the cowbird. Dr. Friedmann (1929) states that at Ithaca, N. Y., the yellowthroat stands seventh in order of the birds most frequently imposed upon by the cowbird. There are many instances on record where the cowbird has been successful in having the yellowthroat accept its eggs and of rearing the young to maturity. However, some circumvent the intrusion by building a second nest over the first containing the egg of the cowbird, a method frequently employed by the yellow warbler. A. W. Butler (1898) writes of a 3-story nest of the yellowthroat as follows: "Mr. E. R. Quick has in his collection a three-story nest of this bird, taken near Brookville, Ind. Two additional nests were built upon the original structure, burying beneath each the egg of the cowbird (Molothrus ater). Thus it outwitted the detestable parasite, and in the third nest deposited her complement of eggs. Similar nests have been found elsewhere, showing that this is not an individual peculiarity, but others of its kind had experimented along the same line."
The northern yellowthroat is host to a number of external parasites of which Harold S. Peters (1936) has identified the louse Ricinus pallens (Kellogg) and the two flies Ornynoica confluenta Say and Ornithomyia anchineuria Speiser.
Fall.--There are so many breeding birds on the migration range of the yellowthroat that it is not easy to mark the beginning of the southward migration in the autumn. The bulk of the birds leave their northern breeding grounds in September, but even in these northern sections many birds linger well into October, a few as late as November. Indeed there are a number of records of birds seen throughout the winter months.
M. B. Trautman (1940) writes of the fall migration at Buckeye Lake, Ohio, as follows: "Upon a few occasions the chip note of night migrating birds was recognized as early as late July, and a few apparent transients were seen dropping earthward in the early mornings. Evidence of migration was always apparent by August 10. The peak of migration took place between late August and late September, and then the species was as abundant as in spring. It disappeared between October 5 and November 2." At Oneida Lake, N. Y., according to D. Stoner (1932) fall migration begins in September and by mid-October practically all of the birds have left the territory.
At the Florida lighthouses, where specimens have been recovered, thus making it certain that individuals of the northern yellowthroat are migrating, the first birds appear about the middle of September. They are reported to reach Cuba during the last two weeks of the month. The earliest arrivals reach Jamaica the first week of October and have been reported in Nicaragua during the last week of October.
Winter.--The winter ranges of the northern and Maryland yellowthroats overlap to a great extent. The records are confusing in certain cases, and we cannot be sure that the races are properly designated. The northern yellowthroat winters from southern United States to the Bahamas and the West Indies and through eastern Mexico to Costa Rica. The Maryland winters from North Carolina and Louisiana to Florida, the Bahamas and Haiti. An adult male was taken by Todd (1922) as far south as the Santa Marta region, Colombia.
Dickey and Van Rossem (1938) have found the northern yellowthroat a common midwinter visitant in El Salvador. They write as follows:
The northern yellowthroat was not detected in the fall, even in localities where later in the year it was present in numbers. It is safe to say that few, if any, reach El Salvador before about January 1, after which date the species is common and generally distributed in marshland, shrubbery along streams, and even in fern bracken up to 8,000 feet in the Arid Upper Tropical Zone.
The northward migration is chiefly during early April. At Lake Olomega from April 1 to 8, 1926, and at San Salvador until April 17, 1912, yellowthroats were very common, much more so than during the winter. However, some individuals remain very late in spring; indeed, locally, they are sometimes actually common in the middle of May. An instance of this is the fact that at Lake Chanmico from May 13 to 17, 1912, brachidactyla was frequently noted in the grass and mimosa scrub about the edge of the lake. A peculiarity of this occurrence was that the birds were usually in pairs. The two males taken were in breeding condition, and the single female had rapidly developing ova.
Dr. Alexander F. Skutch has sent us the following notes concerning the yellowthroat (races not designated) in Central America: "Like so many of the warblers that winter in Central America, the yellowthroats are abundant in the north but rare in the south. In Panama and Costa Rica it has been very rarely recorded; I have seen it only once during eight years in these countries. In Guatemala, it winters in fair numbers at lower elevations, on both sides of the Republic, upward to at least 3,000 feet above sea level. I saw two at Panajachel, 5,000 feet above sea level, in late October; but it is possible that at this date they had not yet settled down for the winter. This single bird I met on the Sierra de Tecpan, at 8,500 feet, on March 7, 1933, was obviously only a transient--I saw no other of the kind during the course of the year. In the lower Motagua Valley, I found the yellowthroat an abundant winter resident; and it was not rare on the great coffee plantations of the Pacific slope. It frequents low-lying pastures where the grass is tall, moist thickets, and the brakes of giant cane along the rivers. Always solitary, it shows no tendency to flock.
"The yellowthroat arrives late and apparently has not been recorded before October. In April, when the migratory movements begin, these birds become exceedingly abundant in the Motagua Valley of Guatemala. They linger into May, rarely past the middle of the month; and I have recorded males as late as females. On May 7,1932, I heard a male, the last of his kind I saw that year, sing repeatedly but rather weakly, among tall, lush grass in the Motagua Valley."
Dr. Barbour (1923) states the northern yellowthroat is a common winter visitant in Cuba, where it is found about marshes, in cane brakes and reed beds, and in lowland thickets of vines and lianas.
In the Isle of Pines, W. E. C. Todd (1916) states that the Maryland yellowthroat is a common winter resident throughout the northern part of the island where it inhabits the low, wet thickets.
In Haiti and the Dominican republic Wetmore and Swales (1931) state: "The yellow-throat is found in numbers at the proper season in weed-grown fields, and the borders of marshes in the lowlands, and also ranges widely into the higher altitudes where there is suitable cover for it. It lives near the ground concealed in the dense growths that it affects, coming out on open perches for a few seconds and then dodging quickly out of sight or flushing with tilting flight to fly for a few yards before disappearing again into its coverts. Attention often is directed to it by its harsh call note, a low chimp, as it scolds whenever disturbed."
So many individuals of yellowthroats have been found wintering well north of the usual winter range of these birds that it has become something more than an accidental occurrence. A few representative records in this connection are of interest. Baillie and Thompson (1928) report that a Maryland yellowthroat was seen December 25, 1927, in a sheltered ravine of Hyde Park, Toronto, Canada. It was a male in good plumage; it was active and uttered its characteristic song. M. B. Trautman (1933) saw a male northern yellowthroat during a severe cold snap during mid-March at Buckeye Lake, Ohio. It was wintering in the cattails which stood beside a 2-foot snow drift at the time it was seen The bird was collected and upon examination was found to be fat and in apparently good condition.
C. W. Townsend (1905) writes: "I found a Maryland
yellow-throat on December 6th, 1903, in the sand dunes just back
of Ipswich Beach, among some bayberry bushes and goldenrod stalks.
There was about an inch of snow on the ground and the thermometer
early in the morning was only 15o F. The bird proved to
be a young male, quite fat, with its stomach filled with insects,
mostly beetles and flies, and a few small seeds. Its plumage was
interesting, as it had partially assumed the first nuptial
plumage." Since Dr. Townsend's winter record there have been
numerous winter records of the northern yellowthroat in
Massachusetts as well as in other sections of New England. The
yellowthroat is a regular winter resident from North Carolina
Common Yellowthroat* Geothlypis trichas [Northern and Maryland Yellowthroats]
*Original Source: Bent, Arthur Cleveland. 1953. Smithsonian Institution United States National Museum Bulletin 203: 542-565. United States Government Printing Office