Contributed by Winsor Marrett Tyler
[Published in 1942: Smithsonian Institution United States National Museum Bulletin 179: 266-279]
Spring.--The long spring migration is drawing to a close. The hardy adventurers of March have settled here in New England for the summer or have passed farther northward. In April the hordes of sparrows swept through the country, and early in May the orioles came back to us from South America. The rush of warblers has mainly passed now, but the last of the blackpolls are marching through, and the northern thrushes, the olive back and the gray cheek, the rear guard of the migration, are hiding in the shadows.
It is at this time of the year, when spring is in full bloom, when the countryside is brilliant green and the forest leaves are almost summer size, that the wood pewee calmly takes his place among the big trees of our woodlands, the shade trees of our streets, and, if the trees be tall, even in our gardens. His slow, sweet, quiet, three-note song tells us that he is here, hidden among the leaves, although the bird remains for the most part so high up in the thick foliage that we may not catch a glimpse of him for weeks unless we look sharply--not perhaps until the young are fledged and descend from their lofty nest and begin to wander about with their parents.
All the way on its journey from the south, the wood pewee has loitered behind the hurrying migrants, leisurely delaying its homecoming, and now, at last on its breeding ground, it finds many of its neighbors with broods already hatched, engaged with the turmoils of parenthood.
Courtship.--The wood pewee seems to have no well-marked ritual in its courtship behavior. He does indeed break away from his characteristic calm and becomes more animated during the short nuptial season, flying about more rapidly than usual and engaging in lively, weaving chases among the branches. Such pursuits, however, apparently constitute, as is the case with many of the smaller birds, the only courtship display. Audubon (1840) says: "During the love season, it often flies, with a vibratory motion of the wings, so very slowly that one might suppose it about to poise itself in the air. On such occasions its notes are guttural, and are continued for several seconds as a low twitter."
Dr. Samuel S. Dickey has contributed to Mr. Bent, in careful, extensive notes, the result of his long study of the wood pewee. These notes will be quoted repeatedly hereinafter. Of courtship he writes: "During the mating period they are unusually vivacious. They tweek their wings and agitate their tails and spring prettily forward. It is no uncommon sight to see two males in combat. They draw up to each other, hover an instant in a clearing, and then in close contact they fall downward together, but before they reach the ground they usually swerve to one side. With squeaking outcries they continue the chase until one bird, tiring of the contest, takes shelter in some distant tree. When a male has found a female to his liking, he pursues her in and out of the avenues between the trees. She will then sometimes disappear into the midst of the body of a tree and leave him hovering in bewilderment close by."
Speaking of the period of courtship, Dr. Thomas S. Roberts (1932) says: "The male Wood Pewee has, besides the usual pee-a-wee, a rapid chattering utterance, delivered as he pursues the female among and over the tree-tops; also, at such times, a few full, sweet notes, almost as though he were about to warble a song and suggesting a phrase from that of the Ruby-crowned Kinglet. This was heard on one occasion (June 20) just at sundown as a pair of Pewees that had a nest near by were indulging in most ardent expressions of devotion, accompanied by aerial evolutions so rapid as to make it difficult to follow them with the eye."
Nesting.--The nest of the wood pewee is a dainty little structure, harmonizing so closely with the surroundings that our eye may easily pass along the limb to which the nest is bound without detecting it. The nest seems tiny for the size of the bird, sits close to the branch--the bottom thin, the walls low and thick--and the outside is sheathed with bits of lichen.
The site of the nest is generally on a small limb, often dead and patched with lichens, commonly at a height of about 20 feet, in or near a level fork well out from the trunk of the tree.
Bendire (1895) states that the bird "shows a decided preference for open, mixed woods, free from underbrush, and frequents the edge of such as border on fields, clearings, etc., either in dry or moist situations," and that "an average and typical nest of the Wood Pewee measures 2 3/4 inches in outer diameter by 1 3/4 inches in depth; the inner cup is about 1 3/4 inches wide by 1 1/4 inches deep."
Arthur C. Bent writes in his notes: "Most of the nests that I have seen have been on horizontal, lichen-covered limbs of old apple trees in orchards, or on dead limbs of pitch pines in the Plymouth woods." The Plymouth woods is a dry, tangled wilderness, extending over many square miles in southeastern Massachusetts, overgrown with pitch pines and scrub oak and interspersed with small ponds.
Dickey, whose investigations were largely conducted in Pennsylvania, gives a long list of trees in which he has found wood pewees' nests. It includes oaks (white, red, and black), sugar maple, black walnut, yellow locust, elm, apple, and pear, generally in specimens of large growth. He has found a nest in a flowering dogwood tree only 8 feet above ground. He says that willows are used rarely, but he speaks of one nest in a partly dead willow tree five feet out from the main stem. Another nest was "in a stalwart sycamore, six feet through at the butt, in a horizontal fork 45 feet aloft and 18 feet out from the main bole."
Ira N. Gabrielson (1922) describes a nest "saddled on a long straight limb of an elm perhaps fifteen feet from the ground and about the same distance from the trunk of the tree. The only foliage on this branch was a spreading spray of leaves several feet beyond the nest. One would think that a nest so located would be easily discovered but such was not the case. While conspicuously located it was cunningly woven onto the branch and so thoroughly covered with lichens that I could scarcely believe it was a nest even after seeing the bird alight upon it. From below it looked to be simply a lichen-covered knot or a small fungus growth upon the limb and only after we were on a level with it did it seem at all conspicuous."
A. Dawes DuBois, describing in his notes a deserted nest, says: "Its inner lining consisted chiefly of stiff, curved, two-branched, wirelike stems resembling the fruit stems of the basswood. tree--some of them 2 inches long. There were about 70 of these. There were also long, hairlike stems of plant fibers, other coarser stems, shreds of weed bark, some 9 inches long, a piece of spider cocoon, and a 3-inch piece of string. At one spot, near the center, the branch itself served as the bottom of the nest. The body of the structure was built of similar but coarser materials. No hair was used in this nest. The outside was well covered with lichens, firmly held in place by cocoon silk."
DuBois also stresses the point that, owing to the situation of the wood pewee's nest--i. e., directly on the bark of a horizontal limb and often not supported in a crotch--the nest must be fastened to the bark. This necessary anchorage is secured by the bird while building who "repeatedly wipes her bill from side to side along the limb, making the materials adhere to the bark."
Bendire (1895) says: "The inner cup of the nest is usually lined with finer materials of the same kind, and occasionally with a little wool, down of plants, a few horse hairs, and bits of thread," and he examined "a unique nest of this species, taken. . .from a horizontal limb of an apple tree, about 8 feet from the ground. . . . This nest, which is well preserved, is exteriorly composed entirely of wool. . . . It is very sparingly lined with fine grass tops and a few horse hairs, while a single well-preserved apple leaf lies perfectly flat and exactly in the center and bottom of the nest."
Ora W. Knight (1908) reports that the male "does not seem to do any active work, either at nest building or assisting in incubation, but I have however seen him feed the female more or less frequently while she was sitting."
The wood pewee appears to become attached to a group of trees and returns sometimes year after year to build its nest on the same branch. Katie Myra Roads (1931) gives an instance of this habit when she reports: "For thirty-five years a Wood Pewee's. . .nest has been placed in the same fork of an elm tree about forty feet from the ground.
The eggs of the Wood Pewee vary in shape from ovate to short or rounded ovate; the shell is close-grained and without gloss. The ground color varies from a pale milky white to a rich cream color, and the markings, which vary considerably in size and number in different sets, are usually disposed in the shape of an irregular wreath around the larger end of the egg, and consist of blotches and minute specks of claret brown, chestnut, vinaceous rufous, heliotrope, purple, and lavender. In some specimens the darker, in others the lighter shades predominate. In very rare instances only are the markings found on the smaller end of the egg.
The average measurements of seventy-two eggs in the United States National Museum collection is 18.24 by 13.65 millimeters, or about 0.72 by 0.54 inch. The largest egg of the series measures 20.07 by 13.97 millimeters, or 0.79 by 0.55 inch; the smallest, 16.51 by 12.95 millimeters, or 0.65 by 0.51 inch.
Young.--The young pewees, generally three in a brood, grow rapidly and soon overfill their little nest. However, in color they match the surrounding bark and lichens so closely that they remain inconspicuous even when, almost ready to fly, the three of them are in plain sight from below, crowded together on a nest that was none too big to accommodate their parent.
Dickey indicates how the young birds prevent themselves from falling out of the nest. "When I attempted to take them from the nest," he says, "they resisted with more strength than one would have supposed they possessed. They grasped the lining of the nest with their claws and pulled it out as I lifted them up."
Burns (1915) gives the incubation period as 12 to 13 days, Bendire (1895) as "about twelve days," and Dickey says: "The eggs were incubated for a period of exactly thirteen days in six nests I had under observation."
A. Dawes DuBois gives in his notes an account of the nest life in a family he watched closely. He says: "On the day of hatching, the single nestling was only a bit of animated fuzz, but by the evening of the next day it had apparently grown to twice its original size--an odd little creature with tufts of whitish gray down on its back and head. When the nestling was four or five days old it was brooded only part of the time. The feeding was done very quickly. The parent brought what appeared to be a small moth; the nestling's head went up, instantly the food went in, the head dropped back, and the parent brooded, all in a second or two without any ceremony. Two days later the nestling was well feathered. Occasionally it stretched and flapped its wings. While being fed it never uttered any sound that was audible to me. The feeding continued to be a very matter-of-fact, well-regulated business; the young one opened its mouth only at the auspicious moment, and the food was quickly gulped down. Excreta were swallowed until the nestling was four or five days old; later they were carried away and discarded.
"During its thirteenth and fourteenth day the nestling was occupied chiefly in stretching up on the edge of the nest, flapping its wings, looking down at the ground or out through the trees, or watching a butterfly if one came near. It fluttered, stretched, dozed, and took nourishment by turns. Occasionally it almost toppled from the edge of the nest but seemed to have no thought of taking a walk on the branch. But the next morning the youngster ventured out to a distance of about 2 feet, and later, purposely dislodged by a parent, I thought, it fluttered to the ground. From here it struck out on its own account, almost reaching the eaves of a low building 30 yards down the slope before again fluttering to the ground."
Bendire (1895) says: "The young leave the nest in about sixteen days, and are cared for by both parents." Knight (1908) gives the period of nest life as "about eighteen days after hatching." Mr. DuBois's bird left on its fifteenth day.
Dr. Thomas S. Roberts (1932) states: "The young, when first out of the nest, sit huddled together in a row, waiting to be fed and voicing their impatience in a plaintive squeak, like a mouse in distress."
Plumages.--[AUTHOR'S NOTE: In the early stages of the juvenal plumage the feathers are soft, fluffy, and blended, but they appear firmer in September with the beginning of the postjuvenal molt. In the juvenal plumage the upper parts are "olive-brown" but much darker on the pileum, the feathers of the crown and rump being narrowly edged with buffy brown; sometimes the entire upper parts have these faint edgings, and sometimes the feathers of the nape are faintly edged with ashy gray; the median and greater wing coverts are tipped with "light ochraceous-buff," forming two distinct wing bands; the central and posterior under parts are "pale primrose yellow," abruptly defined against the "olive-gray" sides of the throat and flanks, with an indistinct pectoral band of olive-gray.
A postjuvenal molt, probably incomplete, begins early in September and evidently is not wholly finished before the birds go south. Whether the wings and tail are molted at this time or later in fall or winter does not seem to be known. Dr. Dwight (1900) says that the first winter plumage "resembles closely the previous dress, but grayish instead of brownish tinged above, the edgings and collar lost and the new wing-bands grayish."
Apparently young birds become practically adult during their first winter or the following spring, perhaps by a complete or partial prenuptial molt.
Adults have a complete postnuptial molt, beginning late in August or in September but chiefly accomplished after the birds have migrated. They may have a partial prenuptial molt before they come north, but we have no specimens to show it.]
The food of the Wood Pewee is almost exclusively derived from the animal kingdom, only a little more than one per cent of it being vegetable. This consists almost entirely of wild fruits such as those of elder, blackberry, dogwood and pokeberry. Spiders and millipeds are eaten regularly but in small quantities, comprising only a little over two per cent of the whole subsistence. Besides the items mentioned the remainder of the food of the Wood Pewee consists entirely of insects. The more important groups are flies (about 30 per cent of the total food), hymenoptera (28 per cent), beetles (14 per cent), lepidoptera (12 per cent), bugs (6 per cent), and grasshoppers (3 per cent). Among forest pests consumed by the Wood Pewee are carpenter ants, tussock and gipsy moths, and cankerworms, click beetles, leaf chafers, adults of both flat-headed and round-headed wood borers, leaf beetles, nut weevils, bark beetles, and tree hoppers. . . . The Wood Pewee consumes also various useful insects, as parasitic wasps, ladybird beetles, and certain others, but on the whole is a very good friend of the wood lot.
F. E. L. Beal (1912), basing his conclusions "upon the examination of 359 stomachs taken in 20 States of the Union, the District of Columbia, Ontario, New Brunswick, and Nova Scotia," says in his summary:
The one point most open for criticism in the food of the wood pewee is that it eats too many parasitic Hymenoptera. There is no doubt that all birds which prey upon Hymenoptera at all destroy some of the useful species, but the proportion in the food of this bird is greater than in other birds whose food has been investigated. As these insects are for the most part smaller than the more common wasps and bees, it would seem natural that they should be preyed upon most by the smaller flycatchers, which very likely accounts for the fact that the wood pewee eats more of them than the kingbirds. But even so the bird does far more good than harm. The loss of the useful Hymenoptera can be condoned when it is remembered that with them the bird takes so many harmful or annoying species.
Walter Bradford Barrows (1912) says: "The food consists very largely of insects taken on the wing, yet it not infrequently hovers before a twig or leaf and snaps up small insects which appear to be stationary, sometimes descending to the grass for this purpose. . . . In Nebraska Professor Aughey found seven grasshoppers and many other insects in the single specimen which he examined."
As we watch a wood pewee feeding--dashing out from its perch repeatedly, often among the interstices of forest trees where the light is not over strong--we are impressed by the large number of very small insects it must capture. These are so small that we do not always catch sight of them in the air, but we may infer their number from the bird's actions, by hearing the click of its bill as it snaps them up, or attempts to do so, and sometimes by seeing more than one insect in the bird's beak after it alights. Forbush (1907) noticed this habit and remarks: "It usually perches on dead branches at some height from the ground, and flies out to some distance, taking one or many insects at each sally."
Dickey in his manuscript states that "the birds flit out from woodland margins to feed in clearings and over corn, wheat and oat fields. They are prone, too, to hover beside the webs of spiders and extract flies that have been snared, and they make repeated trips out over marsh-land and return to the woods, their beaks filled with appendages of insects."
That the food of the wood pewee is not restricted to small insects is shown by A. Dawes DuBois, who reports that he saw a parent bird come to a nest "with a good-sized butterfly, a red admiral, which the young bird swallowed, wings and all."
Bendire (1895) quotes George A. Seagle, superintendent of the Wytheville (Va.) Fish Commission station, who stated: "This little bird has frequently been seen to catch young trout from the ponds soon after they had been transferred from the hatching house."
Behavior.--The wood pewee is an obscurely marked, smallish flycatcher, only slightly larger than the little birds that make up the genus Empidonax. Wilson (1831) says: "It loves to sit on the high dead branches, amid the gloom of the woods." In such surroundings it is not easily seen, for its plumage appears in the field as brownish gray above and grayish white below, colors that harmonize with the filtered light of the forest. In fact, were it not for its voice, we should rarely notice the bird even when it is darting about, high overhead in its leafy retreat. It is a seclusive, apparently peace loving little bird, quiet, although very quick in its motions, and seldom asserts itself, being wholly free from the aggressiveness that marks the behavior of some of the larger flycatchers. We meet it almost invariably alone, or in the company of its mate or its brood of young.
Here in eastern Massachusetts the wood pewee is not a common bird; it has diminished in numbers noticeably during the past 20 years. Both Wilson and Aubudon speak of it as more common than the phoebe. At the present time the reverse is true here, in the proportion, it seems, of ten to one.
Speaking of the wood pewee's relations with other species of birds, A. Dawes DuBois says: "The pewees would not tolerate red-winged blackbirds or red-headed woodpeckers, although they were not agitated by the presence of flickers. With chipping sparrows they were on very friendly terms. The toleration of another species I once saw displayed even in the vicinity of the nest. A least flycatcher was building its deep nest about 60 feet from the ground in a tall slender tree, while a wood pewee sat unconcerned in her own flat nest about 5 feet away in the same tree."
Beatrice Sawyer Rossell (1921) points out an exception to the bird's usual peaceful behavior. She relates: "My attention was suddenly attracted by a Wood Pewee, which flew to a dead twig, not 3 feet above my head. I called my companion's attention to it, and as I spoke the bird darted at my head, coming so close that I instinctively swerved. He flew back to his perch, and in a minute made another dart, almost brushing me with his wings. . . . For a few seconds he fluttered around me, then made a dart and pecked my finger with his sharp little bill."
Ira N. Gabrielson (1922), who had lowered a nest containing three eggs to within 3 feet of the ground, says: "We were regarded with absolute indifference as we approached to within six feet to take a photograph. . . . The brooding bird was not disturbed by my entrance into the blind but as the camera lens appeared in the opening of the blind she left the nest and dashed repeatedly at the lens, snapping her mandibles vigorously. This continued for several minutes before she finally returned to the nest. At intervals during the morning she renewed her attack on the lens but aside from this paid no attention to either the blind or my movements."
Voice.--The wood pewee has a very attractive voice--a sweet, pure, tranquil whistle delivered calmly in short, slow phrases. The leisurely notes, sliding smoothly and evenly as they change in pitch, give the impression of restfulness and peace, almost of sadness. Bradford Torrey (1901) calls the song "an elegy." All day from dawn to dusk it goes languidly on, pee-a-wee, (a pause) peea, phrase after phrase, often with long pauses between them, never hurried, always serene. The song continues well into hot, parched August, when most birds are silent. Aretas A. Saunders (1924), speaking of the uniformity of the wood pewee's singings, says: "Of a number of records made from different individuals at the same season of the year, the majority are likely to be almost, if not exactly, identical."
Perhaps, in the case of the wood pewee, the term song should be applied only to the bird's singing in the half light before dawn and in the evening long after sunset. At these times of day the bird devotes about 40 minutes in the morning and a shorter, less regular period in the evening to singing a song quite different from its daylight notes, a song so charmingly rhythmical that it has attracted the attention of musicians and excited their admiration.
I noticed it for the first time on June 3, 1911, and wrote in my notes: "At 3:40 this morning (sun rose at 4:09) a wood pewee sang over and over with perfect regularity a song of five drawling notes--pee-a-wee, pee-wee--both phrases ending on a rising inflection. The syllables and the pauses between them were so regular that I could time by my breathing. Pee-a-wee corresponded exactly with an inspiration, then, after a short pause the pee-wee finished at the end of expiration. Then a longer pause--just as long as the rest between breaths--and after this he repeated his song with my next breath. I was breathing, I suppose, 16 times a minute, and the bird slowly fell behind, but he fell behind not from any irregularity, but because his rate was slightly slower than mine."
In listening to the twilight song in more recent years I have noted that, as the song goes on and on, a bird will occasionally introduce into it, among the phrases that rise in pitch, a phrase of falling inflection. This phrase brings to the song a restful effect. Indeed, Henry Oldys (1904), taking this infrequent phrase as the final theme of a four-line song, points out "that it is constructed in the form of the ballad of human music." He explains that "the arrangement of the ordinary ballad frequently consists of a musical theme for the first line, an answering theme for the second line that leaves the musical satisfaction suspended, a repetition of the first theme for the third line, and a repetition of the second theme, either exactly or in general character, but ending with the keynote, for the fourth line." Illustrating with a verse of "Way Down upon the S'wanee River," he shows that the wood pewee's song is governed by the same principles, and that the final keynote (of the falling phrase) completely satisfies the ear.
When the bird combines his phrases in this way, as he does from time to time, he converts his long soliloquy into a song of great beauty. But we must bear in mind that it is only through the fortuitous arrangement of its parts that the singing assumes for a moment the ballad form, and that the introduction of the key phrase is purely inadvertent.
Mr. Oldys slyly remarks at the end of his interesting exposition of the twilight song: "In closing this brief account I would call attention to the remarkable fact--perhaps a joke on us--that a bird which we have classed outside the ranks of the singers proper should deliver a song that judged by our own musical standards takes higher technical rank than any other known example of bird music."
The reader is referred also to two articles by Wallace Craig (1926, 1933) analyzing the twilight song.
Taverner and Swales (1907) write of the wood pewees at Point Pelee: "Their voices can be heard any hour of the day uttering their pathetically plaintive note; and often in the night, as we have lain awake in the tent, some Pewee has aroused itself and a long drawn 'pewee' has punctuated the darkness with its soft sweetness."
Harrison F. Lewis, in a letter to Mr. Bent, writes: "On July 12, 1920, I saw a wood pewee dash out of a tree at the height of about 40 feet from the ground and fly wildly and erratically about in a small area, crying rapidly and unceasingly, in a high-pitched squeaky voice, whee-chuttle-chuttle, whee-chuttle, etc., for about half a minute."
I have heard similar notes in midsummer from a pewee perched in a tree--seven or eight short whistled syllables given as a rapid twitter which suggested a goldfinch's voice, and wholly lacked the usual drawling quality of the pewee's.
The wood pewee's call note is a soft monosyllable, lower and less sharply enunciated than the explosive chip of the phoebe.
Francis Beach White, who has studied the voice of the wood pewee for more than 20 years, calls attention to a seasonal variation in the notes. He says: "In the last week of May, prolonged singing analogous to the twilight song is heard, but this is not developed fully until June. In June the notes take on a somewhat richer tone. In July the phee-ew is heard in long series, especially at dawn and after sunset, and excited jumbles of song notes may also be heard occasionally, as well as antiphonal calling. In August, notes of more emotional tone are given, and toward the last of the month pu-ee is often heard with a strident element in the last syllable. The human reaction to the notes endues the last-mentioned call with a petulant anxiety, and the twilight song with a paradoxical mournful happiness."
Field marks.--The following excellent differential diagnosis is quoted from Ralph Hoffmann (1904): "The long-drawn song, when given, distinguishes the Wood Pewee from any of the other Flycatchers, but when the bird is silent it may be confused either with the Phoebe or with the Chebec. It may be distinguished from the former by its smaller size and by its well-marked wing-bars; moreover, it never flirts its tail after the manner of the Phoebe. It is considerably larger than the Chebec, and, when it faces an observer, the middle of its breast shows a light line separating the darker sides."
Dr. Friedmann (1929) calls the wood pewee "a not uncommon victim of the Cowbird. . . . As many as four Cowbird eggs have been reported from a single nest of this species, but such cases are extremely rare. . . . About 3 dozen records have come to my notice but these probably represent a small percentage of the cases found."
Fall.--At Point Pelee, Taverner and Swales (1907) found wood pewees "very abundant in the early days of fall. It is evident that the first fall movement of this species begins early in the season. The 24th of August, 1907, we found the woods of the Point already in possession of innumerable hosts of Wood Pewees, and through early September we have always found them the most prominent bird in the landscape."
Alfred M. Bailey and Earl G. Wright (1931), writing of southern Louisiana, says: "In November it is fairly numerous, and one of the delights of still hunting for deer along the wooded regions, is to watch the small birds working through the tree tops. Small warblers are ever on the move, but the pewee often sits motionless on twigs over the water, and then comes suddenly to life long enough to flutter into space, seize an insect, and drop back to perch."
William Brewster (1937) gives an instance of a young wood pewee caught by inclement weather in northern Maine late in the season:
1899, October 1.--A bitter day for the season with harsh
north-west wind, over clouded sky and frequent flurries of snow
melting as fast as it struck the ground in the lowlands, but
whitening the mountain crests from morning to night. Visiting our
boat-house by the river-bank in Upton this afternoon I was not a
little surprised to find a Wood Pewee there, cowering under the
lee of the building with ruffled and somewhat bedraggled plumage,
looking benumbed and disheartened. Nevertheless its eyes shone
brightly and it made occasional dashing forays among the thick
falling snowflakes apparently mistaking them for white-winged
insects or at least treating them as such. It spent most of its
time, however, on the ground, or rather on piles of chips and
pieces of boards, where it fluttered or hopped from place to place
picking up food the nature of which I failed to ascertain.
Eastern Wood-Pewee* Contopus virens
*Original Source: Bent, Arthur Cleveland. 1942. Smithsonian Institution United States National Museum Bulletin 179: 266-279. United States Government Printing Office