Willow Flycatcher

Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.

Bent Life History for the Willow Flycatcher – the common name and sub-species reflect the nomenclature in use at the time the description was written.

The western race of Traill’s flycatcher, for which the above name is now accepted, is widely distributed in western North America.

The 1931 Check-list states that it “breeds from extreme southwestern British Columbia, northern Washington, central Idaho, and central Wyoming south to northern Lower California, southern New Mexico, central Texas, and Durango.” It is an abundant summer resident in all suitable localities, “its favorite haunts being the willowcovered islands and the shubbery along water courses, beaver meadows, and the borders of the more open mountain parks; in such places it sometimes reaches an altitude of 8,000 feet in summer, especially in California, Colorado, and Utah,” according to Major Bendire (1895).

S. F. Rathbun writes to me that the little flycatcher is a common summer resident in western Washington and has a very uniform distribution. “It is a bird of the lowlands, seldom met with at any considerable elevation; and it appears to prefer quite open places more or less overgrown with shrubs or bracken or both, the location of which is along the margin of a mixed growth of trees, mostly deciduous, with water or low ground not far away. And should any locality of this kind remain more or less unchanged, it is very apt to have a pair of these flycatchers resort to it year after year.”

W. L. D.awson (1923) says that, in California, it “is a lover of the half-open situations, bushy rather than timbered, of clearings, low thickets, and river-banks. Above all, it is wedded to the lesser willows, Salix flavescens, S. lasiolepis, S. sesailifoZia, and the rest. TJnlike its congeners, it will follow a stream out into the desert, if only a few willows or cottonwoods will keep it company.” He also found it in the heart of the Sierras, “though not often to altitudes above 6,000 or 7,000 feet. * * * The highest elevation at which I have ever found this species breeding is at Mammoth Camp, in southern Mono County, at an elevation of 8,000 feet.”

Grinnell and Storer (1924) say: “The Traill adheres closely to the cover of thickets; it must be looked for beneath the level of the willow tops. It is thus very different in perch predilection from most of the other Empidonaces.”

Nesting: Mr. Rathbun says (MS.) that in the vicinity of Seattle, Wash., this flycatcher does not appear to arrive until about the middle of May or later. “The many records we have indicate its nesting period to be from about the middle of June until well into July. Ususally the nest is placed at a height of only a few feet in some small bush, and often in a large bracken, if any such are in the bird’s territory, for this growth seems to be favored by this flycatcher. Once I found a nest in a small clump of willows standing in quite a depth of water, my attention being attracted to the nest by its size and the many dry, long grasses dangling from it. This flycatcher’s nest is a neat affair, somewhat loosely made of various kinds of dried plant material, such as bracken, fibers of weed stems, coarse grasses, and bits of moss; sometimes vertically woven into the structure are a few stiff straws or weed stalks, as if for strength; next is a thin layer of soft material, which is lined very often with the reddish flower stalks from ground mosses.”

L. B. Howsley, of Seattle, Wash., has sent me some elaborate notes on the nesting of the little flycateher, from which I quote as follows: “The nesting site selected is usually the forks of the large field fern [presumably the western bracken, Pterid~um aguilinasm var. pube.8censl, so common in this section of the country. In some portions of the western part of the State, this fern grows over 6 and 7 feet high, and the plants are so thick that they constitute miniature forests. Wherever they are available, usually in an open parklike site, the little flycatcher seems to prefer it, possibly for concealment or protection, as the fronds afford both. This flycatcher is one of the commonest birds in this area, and scarcely a fern patch is without a summer resident. The height of the nest averages 3 feet, my records showing the lowest as 30 inches and the highest as 5½ feet up. The fork of the fern is always used, preference being given to a 3-. or 4-way fork: this, undoubtedly, for the extra support. To the surrounding stems, the nest is securely tied with shreds of weed bark.”

The building program, based on four observations, but perhaps not the invariable rule, he divides into the following operations:

“(1) The placing of a bunch of semidecayed weed bark, lint, and bleached, dead grass. This platform is used by the bird in the future construction work. (2) The bird then ties the framework of the nest to each support, starting at the bottom until halfway up. Then the top support, which will eventually be the upper edge of the outside dimension, is next tied before the balance is tied in. (3) After the skeleton has been completed, more miscellaneous foundation material is piled in the bottom, rather loosely, no special attention being paid to the ragged ends and somewhat unshapely contour. (4) When the construction has reached the proper height, the filling in of the nesting cup begins, weaving and tying in vegetable fibers until the inner cup frame has been reached! (5) At this point the rather haphazard actions of the builder lose all carelessness, and the final touches are affixed with a great deal of care and much attention to detail. The completion of the cup consumes about one-third of the total time necessary to finish a nest.

“The total construction time was 5 to 7 days; and in one instance laying started before the inside cup finish was completed. A day or so is usually spent in tucking in the stray ends and binding down the outside wi~ h what appeared to be a very fine vegetable fiber or spider web. 1 have a nest neatly bound with spider web.

“The materials comprising this flycatcher’s nest can virtually be called standard. Almost invariably the outside is of weed bark and fiber, and soft, bleached grasses, well bound together. The cup consists of a thin layer of very fine grasses, horse hairs (where available), and the inevitable small bits of vegetable down. Sometimes the rim is decorated with a few small feathers, often lightly and neatly bound.

“One nest was placed 4 feet up in a dense tangle of thimbleberries at the bottom of a deep draw, one placed 3 feet up in a shittim bush, one in a small swamp maple 3 feet up on an open hillside, and one in a wild rose bush 3 feet up in dense brush, near a trail. Aside from these, all others observed were in ferns, in cleared brushlands or overgrown fields.”

Three California nests and one Arizona nest that I have seen were all placed in upright or slanting forks of willows, securely fastened between the forks or supporting twigs, at heights varying from 4 to 6 feet above ground. The materials used were essentially the same as those mentioned above, but considerable willow cotton was mixed with the other material. Dr. R. T. Congdon has sent me some photographs of a nest in a raspberry bush in an orchard, near Wenatchee, Wash. Bendire (1895) mentions a nest, found by Dr. Clinton T. Cooke, near Salem, Oreg., that was 18 feet from the ground in the upright crotch of a slender willow. Nests have also been found in alders and blackberry bushes, sometimes as low as 1 foot from the ground. Nests placed in upright crotches are usually in the shape of inverted cones, and sometimes measure as much as 5 inches in height, though usually much less; two that I measured were only about half that height and ahout 3 inches in outer diameter, and the inner cavity was about 2 inches wide and 11/2 inches deep. The nests are generally well and compactly built, but some are rather flimsy.

Eggs: The number of eggs to a set varies from two to four and is usually three or four. They are ovate to short-ovate, generally the former, and they have practically no gloss. The ground color is pure dead white, creamy white, pale huffy white, or rarely has a slight pinkish tinge. Some few eggs are immaculate, but almost always they are more or less marked with fine dots, spots, or small blotches, mainly about the larger end. The markings are in various shades of light, reddish brown, such as “vinaceous-rufous” and “ferruginous.” The measurements of 50 eggs average 17.8 by 13.3 millimeters; the eggs showing the four extremes measure 19.3 by 13.7 18.8 by 14.7, 15.5 by 12.7, and 16.3 by 12.4 millimeters.

Young: Bendire (1895) says that “only one brood is raised in a season, and incubation lasts about 12 days; the young are fed on insects of various kinds, and remain in the nest about two weeks.”

Mrs. Irene G. Wheelock (1904) writes: “Only the mother bird broods in the beautiful nest; the male simply straddling the edge in masculine helplessness when left in charge, looking very wise but really quite useless so far as keeping the eggs warm is concerned. In twelve days queer naked bits of bird life fill the cradle, and now the small brown master is full of importance. They are hungry; away he darts for food, but the demand is ever greater than the supply. To satisfy these four open mouths means a trip every two minutes or oftener. No time has he now for scrapping or bullying his little wife. From early morn he must hustle, snatching time for a hastily swallowed bug en route if he can, going hungry if he must.”

Plumages: The sexes are alike in all plumages, and the young in juvenal plumage is essentially like the adult, except that the upper parts are of a browner olive and the wing bands are buff or “cinnamon-buff.” Both young and adult birds migrate southward before molting, and the young birds retain the juvenal remiges and rectrices through the winter and have a complete prenuptial molt in April, according to Dickey and van Rossem (1938). They say of the adults: “A specimen taken September 3 has just commenced the molt, while one taken on the 29th has nearly completed the body molt and is halfway through the primary molt. One of those taken February 3 is in very fresh plumage, and it is not unlikely that brewaterz, as in the case of the allied form, sometimes drags along with the wing molt until late in the winter. In the spring there is a complete body molt, which is finished just before the northward migration in April.”

Food: The food of the little flycatcher is essentially the same as that of the alder flycatcher, due allowance being made for the difference in the ranges of the two forms. This subject is treated more fully under the eastern subspecies, to which the reader is referred. Professor Beal (1912) says: “No special differences in the food habits have been noticed, and as many of the stomachs used in this investigation were collected before the two forms had been clearly distinguished, it is not practicable to separate them now. * * * It is evident from the nesting habits of this species that it is not likely to injure any product of industry, and the contents of the stomachs examined corroborate this observation.”

Behavior: Mrs. Wheelock (1904) has this to say about the behavior of the little flycatcher:

It Is restless and energetic, flitting about among the bushes but keeping out of sfght except when a too enthusiastic sally after a passing Insect betrays Its whereabouts. But for this and a habit It has of calling out In a fretful tone at the approach of any person, it would never be noticed, so small is it and so well concealed by the waving leaves. S * * Although so busy, this Flycatcher is never so occupied as to miss a chance of driving another bird, great or small, away from the special clump of alders which the pugnacious mite has pre~mpted for his own. When there is no one else within scrapping distance, he contents himself with scolding his mate on the nest. Apparently nothing suits him from the time the nest site is chosen until the brood is reared.

Major Bendire (1895) says: “They never remain long in one place, but move from perch to perch, snapping up insects as they fly; they are pugnacious, quarrelsome little creatures, making up in courage and determination what they lack in size. I have seen one drive a Red-shouldered Blackbird away from the vicinity of its nest, pitching down on it angrily and pecking at its head and neck in the manner of its larger relatives when chasing Crows or Hawks.”

Voice: Ralph Hoffmann (1927) gives the song as “an explosive weeps-a-pid4ea” and says: “The vigorous four or five syllabled song, given in one utterance, with the characteristic emphasis at its close, is quite unlike that of any of the other small flycatchers. The song is occasionally shortened to the last two syllables, pi-d~ea and is often preceded by an explosive jin’rit. Besides the song the Trail Flycatcher utters constantly a sharp whit and, when two birds quarrel, a grating twitter.”

Dawson (Dawson and Bowles, 1909) evidently thought that the notes are “not always distinctive. Particularly, there is one style which cannot be distinguished from the commonest note of the Hammond Flycatcher, switchoo, 8weechew, or unblushingly, zwe~lew, zw~bew, zzweet. Other notes, delivered sometimes singly and sometimes in groups, are piso6; swit’oo, 8weet, 8w~t’oo; Si~ee, kutip, kutip; fiwit or hooit, softly.”

Bendire (1895) gives a slightly different version: “One of their common call notes sounds like ‘queet-queet,’ and the alarm note uttered when the nest is approached is something like that of Traill’s Flycatcher, ‘whuish-whuish.’ When pursuing each other during the mating season, they sometimes give vent to a twittering note, not unlike that of the Arkansas Flycatcher, and a sharp ‘qu~t-qu6~t’ is often heard while these restless little beings flit about in the low willows, or when perched on some tall weed or coarse marsh-grass stalk.”

Mr. Rathbun says in his notes: “It is one of the earliest birds to begin to give its calls in the morning, and often these continue in a rapid way for two or three hours, then gradually grow less; and no matter whether the sun shines or it is raining, neither condition seems to have any effect on the frequency or the strength of the flycatcher’s notes.

“In midsummer, after the little flycatcher’s nesting time is over, and when many of the other birds are silent, its notes will still be heard almost each day, though more so near the close, also occasionally after sunset; and this is the case until well into August, after which they wholly cease.”

Mr. Ilowsley contributes the following notes: “During the earlier mating period, it is common for this flycatcher to give the jyre-pe-de~ call, not pre-pe-de& like the western flycatcher, but a short, snappy, dead tonal sound. Later, this note changes to z’we~-beok, just as short and snappy. This call is given altogether after mating has been completed and nesting begun, the pre-pe-de~ not being heard afterward. In the earlier stages of courtship, several birds were heard to mix the two calls, sometimes using one, sometimes the other.

Field marks: As stated in this paragraph under the other species, the four common, western Empidonaces are difficult to recognize in life by color or markings; they have no prominent field marks, though, as Dawson (Dawson and Bowles, 1909) says, “comparing colors, Traill’s gives an impression of brownness, where the Western is yellowish green, Hammond’s blackish, and Wright’s grayish dusky. These distinctions are not glaring, but they obtain roughly afield, in a group where every floating mote of difference is gladly welcomed.” The notes of the four species are quite distinctive, and they are commonly found in quite different types of habitat. None of the other three is likely to be seen in the low, dense, moist thickets frequented by the little flycatcher.

Enemies: Both subspecies of Empidon&o frailli are rather uncommon victims of the cowbirds of their respective regions, except in southern California and Colorado. Dr. Friedmann (1929) says: “Forty records have come to my attention, two from Colorado, and the rest from California.”

Winter: The fall migration must start very early in August, for Dickey and van Rossem (1938) say:

The first fall arrivals of this species appeared August 14, 1925, in the flooded forest at Lake Olomega [in El Salvador], and within a few days it became extremely common all through the undergrowth. By far the greater part were of the western subspecies, brew*teri. During the winter Tralil’s flycatchers were fuuy as abundant as during the fall, and as many as fifty were seen in one day in the willows and shrubbery along the San Miguel River. Out of four specimens taken at random in that locality on February 3, 1927, three were brew8ter~ and only one was traWii. Between April 1 and 12, 1927, during the spring migration, these flycatchers were literally swarming in the underbrush of the sandy peninsula at Barra de Santiago. Three specimens taken were all brewsteri.