MacGillivray’s Warbler

The MacGillivray’s Warbler has greenish upperparts, a gray head and throat, and yellow underparts.  It has a white arc above and below each eye.

Males have a black bib between the gray throat and yellow underparts.  Length: 5 in.  Wingspan: 7.5 in.

Females have a paler gray head and throat.

Fall birds are similar to spring birds

Fall immatures are paler gray on the head and washed with greenish.

MacGillivray’s Warblers inhabit willow thickets and dense undergrowth.

MacGillivray’s Warblers eat insects.

MacGillivray’s Warblers forage on or near the ground, hopping in search in insects.

MacGillivray’s Warblers breed across much of western Canada and the western U.S. They winter in Mexico and Central America. The population is stable.

More information:

Bent Life History

Visit the Bent Life History for extensive additional information on the MacGillivray’s Warbler.

The MacGillivray’s Warbler is closely related to the Mourning Warbler, which occurs in the eastern U.S. and Canada.

The common name of MacGillivray’s Warbler honors a Scottish ornithologist named William MacGillivray, while the scientific name tolmiei honors the naturalist William Tolmie who first collected the species.

The song is a series of churring notes.  A hard “chik” call is also given.

The MacGillivray’s Warbler’s nest is a cup of leaves, grasses, and weeds and is lined with finer materials. It is placed low in a dense thicket.

Number: Usually lay 4 eggs.
Color: Whitish with darker markings.

Incubation and fledging:
The young hatch at about 11-13 days and fledge at about 8-9 days, though remaining dependent on the adults for some time.

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 MacGillivray’s Warbler – the common name and sub-species reflect the nomenclature in use at the time the description was written.

Westerners seem to prefer to call this bird the Tolmie warbler, a most appropriate name, on which W. L. Dawson (1923) makes the following pertinent comment:

J. K. Townsend discovered the bird and really puplished it first, saying, “I dedicate the species to my friend, VI. T. Tolmie, Esq., of Fort Vancouver.” Audubon, being entrusted with Townsend’s specimens, but disregarding the owner’s prior rights, published the bird independently, and tardily, as It happened, as Sylvia macgillivrayi, by which specific name it was long known to ornithologists. Macgillivray was a Scotch naturalist who never saw America, but Tolmie was at that time a surgeon and later a factor of ‘the Honorable the Hudson Bay Company,” and he clearly deserves remembrance at our hands for friendly hospitality and cooperation which he invariably extended to men of science.”

This pretty warbler closely resembles the eastern mourning warbler in general appearance; it frequents similar haunts and is much like it in all its habits. Its breeding range covers a large part of western North America from southeastern Alaska to central California and New Mexico, including the Rocky Mountains and their foothills. Over most of this region it seems to be more abundant than is the mourning warbler in the East.

Samuel F. Rathbun, of Seattle, Wash., says in his notes that MacGillivray’s is “a rather common warbler throughout the region, but of unusual distribution. It is partial to localities more or less covered with new growth, particularly if this happens to be scattered among a confusion of dead and fallen trees, through which a fire has swept at some little time previously, and over which nature is beginning to throw a covering of young growth, this having a somewhat open exposure. If such spots are contiguous to low ground, they seem more apt to be frequented by this warbler; but at times it will be found in dry sections of this same rough nature.

In Montana, according to Aretas A. Saunders (1921), it is “a common summer resident of the western half of the state, ranging east to the easternmost mountains, and occurring occasionally in migrations to the more eastern parts of the state. Breeds in the Transition zone in clumps of willow and alder, wild rose or other shrubs, mainly in moist situations along the foothills or lower mountain canyons.

Gabrielson and Jewett (1940) say: “In western Oregon, it frequents the blackberry patches and dense thickets of Spiraea or Salal , and in the eastern part of the State, it is equally at home in the dense growth of willow about the springs and along the stream bottoms.”

Dawson (1923) says of its California haunts: “Brushy hillsides not too remote from water, or dense shrubbery partially shaded by trees, afford ideal cover for this handsome warbler and his all but invisible spouse. Mere chaparral will not do either, for the bird loves moisture, and a certain tang in the atmosphere, found in California in the humid coastal counties and on the middle levels of the northern Sierras. Variety, also, is his delight; and after temperature, variety in cover seems to be the bird’s requirement; and a great confusion of shrubs, willow, alder, ceanothus, chokecherry, serviceberry, chinquapin, or mountain mahogany suits him best.”

Mrs. Amelia S. Allen writes to me: “About 500 feet beyond our house in Strawberry Canyon in Berkeley, Calif., there is a little draw, running down an oak-covered north slope, in which are many thimbleberries, trilliums, ferns, and brakes. It is occupied each summer by a pair of Tolmie warblers, and I hear their notes from my bedroom window. I always expect to hear it on the seventh of April. In 1940, it was singing on April 2, and I have a few firsts on the fourth, sixth, and eighth. A walk up the canyon the second week of April usually shows four or five singing males, each one in its regular location year after year.”

Nesting: Rathbun has sent me his notes on several nests of MacGillivray’s warbler found near Seattle, Wash., all of which were built in salal bushes at heights varying from 2 to 3 feet above the ground. One was “on a somewhat open side-hill not far from an old path. It x~ as very much concealed, and found only by carefully examining each bit of growth thoroughly.” Another was “near an old path running through a somewhat open spot in a forest, overgrown with salal shrubs, the ground being littered with old logs above which many of these shrubs thrust their tops”; it was quite plainly seen as he stood on one of the logs. He describes a third as follows: “The location of this nest was in a small clearing on a rather open hillside with scattered second growth, mostly of small firs, with stunted salal shrubs growing about. In one of these latter the nest was built about a foot above the ground and quite plainly to be seen, having the appearance of an old nest, apparently because it was so carelessly constructed. It was outwardly composed of dry weed-stalks, next to which were finer weed-stalks and straws; the lining was of soft dry grasses, fine rootlets, and a few horsehairs. On the top of the nest, effectually concealing the eggs from view, was placed a dead salal leaf, its point and the end of its stem being lightly caught just under the inside edge of the nest, this being, in our opinion, done by the bird with the intent of concealing the eggs on account of the exposure of the nest; it could not have fallen and assumed any such position.”

He refers to another nest in which some fine twigs were used. He gives the measurements of two nests in inches; the outside diameters, respectively, were ~½ and 4′,4, outside height 214 and 3, inside diameter 21/2 and 2, and inside depth 11/s and 1½. Three other nests were in Spiraca bushes, and one was in a little fir.

A. D. Du Bois has sent me the data for three nests found in Flathead County, Mont.; one of these was 2 feet from the ground in a yew bush at the side of a tie-hauling road, in the edge of some woods at the base of a foothill; another was ~’/2 feet from the ground in a balsam fir sapling at the side of a trail.

J. Stuart Rowley writes to me: “On June 16, 1938, while trout fishing along Mammoth Creek, Mono County, Calif., I found two nests of this warbler located in the same general situation and each contained four fresh eggs. The nests were well concealed in thick shrubs along the wet creek bottom and were placed about a foot from the ground. Both females scolded when flushed from the eggs, whereupon the respective males immediately joined in the chirping. It is my firm belief that one will find more warbler eggs while trout fishing than while actually looking for nests.”

In the Yosemite region, Miss Margaret IV. Wythe (1916) found a nest of the Tolmie warbler, nine inches above the ground in a clump of blossoming chokecherry.

The structure was placed between four stalks of the chokecherry, and was supported below by several short twigs growing from the root stock. The materials were not woven around the four upright stalks, although several grass blades passed behind one of them. Materials of which the nest was composed were fine dry grass blades and stems, and several shreds of bark about three-eighths of an inch wide. These latter were woven into the outer part of the structure, where a single oak leaf also lay embedded, whether purposely or by accident, I cannot say. The lining was of fine grasses and a few black horsehairs. Some loose grass arched over the top, attached to the nest a little on one side. Later on the two openings thus made by these arching grasses made a sort of entrance and exit, the bird invariably entering on one side and leaving on the other.

Although, most of the nests of MacGillivray’s warbler are placed near the ground, some of them practically on the ground, a few have been found from 3 to 5 feet up in bushes, scrub oaks and alders.

Eggs: MacGillivray’s warbler lays from 3 to 5 eggs in a set, most often 4 and very rarely 6. The eggs are ovate and slightly glossy. The white, or creamy white, ground color is speckled, spotted or blotched with “auburn,” “chestnut,” “bay,” or “cinnamon,” with spots or undertones of “light brownish drab,” “pale vinaceous-drab,” or “Quaker drab.” Some eggs are delicately marked, while others maybe clouded. On many, even the delicately marked types, are often scattered a few spots, or small scrawls, of very dark brown or even black. Occasionally, these scattered dark spots or scrawls are the only apparent markings, the lighter browns lacking and the undertones almost imperceptible. While the markings are generally concentrated at the large end, there is not as great a tendency to form a wreath as in many of the warblers’ eggs. The measurements of 50 eggs average 17.8 by 18.6 millimeters; the eggs showing the four extremes measure 19.4 by 15.1, and 16.4 by 12.7 millimeters (Harris).

Young: The nest watched by Miss Wythe (1916) held four eggs on June 13, on which the female had been incubating for an unknown period; on the twenty-third two of the eggs had hatched, and the third egg hatched the following day; the incubation period was, therefore, at least ten days. When first hatched, the nestlings had “scarcely a trace of down on them.” One the following day, they “were now scantily covered with down, a patch showing on top of the head, a line down the middle of the back, and a tuft on the wings. * * * On June 27 I spent an hour during the morning timing the feeding of the three young birds, from a point about twelve feet distant. I found that the female warbler came with food at intervals of from three to five minutes throughout the hour. On the fourth day after hatching, “juvenal feathers had appeared over most of the head, down the center of the back, and on the wings. The eyes of one bird were open. On the following day the eyes of the second bird were open. * * * The sixth day showed juvenal feathers appearing on the lateral tracts, and tail feathers just beginning to grow out. On the seventh day, June 30, the wing feathers had broken through the sheaths for about one-half an inch. The birds’ heads were well covered with feathers, but the sheaths still adhered to the bases. The contour feathers were in a similar condition. The tail feathers did not show any further development. On July 2, the ninth day after hatching, the two older birds left the nest, followed later the same day by the third bird, the latter having been in the nest only eight days.

Based on the findings at four nests, Grinnell and Storer (1924) state that “eggs are laid on successive days, incubation begins immediately upon the laying of the last egg or possibly before, and is completed in 13 days, the young hatch on the same day, or on two successive days, and leave the nest S or 9 days after hatching. The male seems to participate but little in caring for the brood.”

Plumages: The molts and plumages of MacGil]ivray’s warbler parallel those of the mourning warbler and need not be repeated here. In the juvenal plumages the two species are practically indistinguishable, except that the former has a longer tail. The differences in later plumages are referred to under field marks. Dickey and van Rossem (1938) have this to say about the prenuptial molt: “In February and March there is a body molt, apparently much more extensive in the young than in adults. The former at this time take on the bluish head and chest of maturity. There is some individual variation, but in general it may be said that the extreme richness of coloration is not attained until the second year. The spring plumage of older birds is the result of a limited renewal plus the wearing away of the paler colored tips of the fall plumage. It takes place in February and March at the same time as that of the younger birds.”

Food: Mrs. Bailey (1928) lists in the food of this warbler “insects, including the click beetle, dung beetle, flea beetle, caterpillars, and the alfalfa weevil.” No comprehensive study of its food seems to have been made.

Behavior: MacGi]livray’s is the same timid, shy, and elusive little bird as its eastern counterpart, the mourning warbler. Gabrielson and Jewett (1940) write: “The birds are much in evidence in their chosen haunts in late April and early May while the courtship is in progress, but when household cares occupy the daylight hours they become as elusive as field mice, slipping about through the thickets like shadows, only the sharp alarm note betraying their presence to an intruder.”

Voice: Rathbun says in his notes: “Its song begins with three or four quickly given notes on nearly the same key, followed by several on a lower key, but this may be varied at times. It is a quite distinctive song and when once learned is not easily forgotten. Throughout there seems to be a minor key; the song lacks smoothness and when heard at a distance has somewhat of a roughness; but, like so many of the songs of birds, it is heard at its best when one is close to the singer. Should its chosen territory be infringed upon, the intruder becomes aware of its presence by hearing a rapid, harsh alarm note, which may be repeated many times.” Du Bois tells me that the song of MacGillivray’s warbler “resembles the syllables te-te-te-te-cheweet-cheweetcheweet, the first part being about a note higher than the latter part. It is uttered rapidly, the whole song requiring about a second and a half. Sometimes there are only three te’8, followed by four cheweet’s.”

Mrs. Amelia S. Allen writes to me: “The song of the Tolmie warbler is more musical than most warbler songs. The first half of the song is composed of double notes with a rising inflection; the second half with a falling inflection: Swee-e4t, swee-eet, swee-elt, pedehy, pedchy, pedehy. But I hear also: Pedehy, pedehy, pecichy, twit twit twit, the first half with a falling inflection.” Grinnell and Storer (1924) write:

At Hazel Green, on May 14, 1919, a bird was observed fully 50 feet above the ground on one of the lower branches of a large incense cedar. * * This bird sang ten times in two minutes, changing position usually after singing twice on one perch. The song was rendered by the observer sink, sir ik, sink, Upik, lipik, Uttle change being detected in successive songs. In the first three “words” the “z” sounds were strong, whereas the last two were more liquid. In singing, the bird would throw its head back, and put much bodily effort Into the process of utterance. Soon the bird dropped close to the ground and sang from within the shrubbery, changing his position frequently. The sharp isip of the female was beard at this time. After a few songs the male flew up to a perch 30 feet above the ground, sang twice, and then went below again. * * * Other Individuals studied and timed while they sang gave their songs at Intervals of 10 to 14 seconds. Song production Is not continuous, however. * * S The “z” sounds heard from the bird at Hazel Green are entirely lacking In other songs studied. Two of these clearer utterances we wrote as follows: syr-pit, syr-p’lt, syr-pit, apr-sip-sip-si p-sip (3G.), and another cheek-a, cheek-a, cheek-a, cheek-a, chee-e-e-e (T.I.S.). The first syllables are loud, clear, and set off from one another, while the shorter ones (sip) are given rapidly, faster than a person can pronounce them, and sometimes are run almost into a trilL

Field marks: MacGillivray’s warbler is quite unlike any other western warbler. Its dark gray head, neck, and upper breast, the latter almost black, its olive-green back and its bright yellow under parts are distinctive in the adult male. The female and young are similarly marked, but the gray is much paler, sometimes grayish white. Where its range approaches that of the mourning warbler, the two white spots above and below the eye of the adult male will distinguish it. The young bird is less easily recognized, but in all plumages the tail of the western species is the longer.

Enemies: This warbler is seldom bothered by the cowbird; I can find only four published records of such parasitism.

Winter: Dr. Alexander F. Skutch contributes the following: “MacGillivray’s warbler is an abundant winter resident over the whole highland area of Guatemala, from 10,000 feet down to at least 2,000 feet on the Pacific slope. Avoiding the forest, it lurks near or on the ground on bushy mountainsides and in low, dense thickets: just such habitats as, at lower altitudes in Costa Rica, are chosen by the closely similar mourning warbler. So well do these birds remain concealed, as they forage screened by the foliage, that the birdwatcher must learn to recognize their distinctive, sharp tuc, tue in order to gain a jMst motion of their abundance; were he to rely upon sight alone, he would call them everywhere rare. Like nearly all birds of similar habits, they live in solitude rather than in flocks.

“MacGillivray’s warbler arrives in Guatemala during the second half of September, and departs early in May. On the Sierra de Tecp~n, they were much more in evidence at the end of April than tiley had been earlier in the year, suggesting that the population of wintering birds had been augmented by transients from farther south, for the species winters southward to Colombia. In Costa Rica they appear to be very rare, in sharp contrast to their abundance farther northward.

“Early dates of fall arrival in Central America are: Guatemala: passim (Griscom), September 23; Sierra de Tecp{in, September 26, 1933; Huehuetenango, September 19, 1934; Colomba, September 24, 1934. Costa Rica: San Jos6 (Underwood), September 25, 1898.

“Late dates of spring departure from Central America are: Guatemala: passim (Griscom), April 26; Sierra de Tecpin, May 10, 1933.”

In El Salvador, Dickey and van Rossem (1938) record MacGillivray’s warbler as a: common midwinter visitant and spring migrant to the upper foothills and mountains, from 2,300 feet on the Arid Lower Tropical Zone to 8,000 feet in the Humid Upper Tropical. * * * MacGilliv ray’s warhiers did not arrive until much later than 0. philadelphia, hut after the first week of December they were to be found everywhere in underbrush in the higher foothills and mountains. On Mt. Cacaguatique they were noted in ravine growth along watercourses; on Volchn de Conchngua among the pines in company with blackthroated green warbiers; on Volchn de San Miguel in the head-high grass of the lava gullies; and on Los Esesmiles in clearings and in natural open spaces in the cloud forest. A fairly cool temperature rather than any particular plant association seems to be the primary factor governing their choice of winter quarters.

DISTRIBUTION
Range: Southern Alaska, western Canada, and the. United States south to northwestern South America.

Breeding range: MacGillivray’s warbler breeds north to southern Alaska (Port Snettisham); central Alberta (probably Peace River Landing, Lesser Slave Lake) and Edmonton); and southwestern Saskatchewan (Cypress Hills). East to southwestern Saskatchewan (Cypress Hills) ; southwestern South Dakota (Black Hills); and through the mountains of central Colorado to New Mexico (Alto and Arroyo Hondo Canyon). South to southeastern New Mexico (Alto); central Arizona (San Francisco Mountains and White Mountains); northern and central Nevada (Galena Creek, Toyabo Mountains, and Baker Creek) ; and central California (Paicines, Placerville, Yosemite, Sequoia National Park, Kern River, White Mountains, and Berkeley). West to central California (Berkeley) ; northeastern Oregon (Powder River Mountains) ; northwestern and central British Columbia (Telegraph Creek, Doch-da-on Creek, Hazelton, Summit Lake, and Yellowstone Lake) ; and southern Alaska (Boca de Quadra, Bradfield Canal, and Port Snettisham).

Winter range: The species winters north to southern Baja California (La Paz, El Triunfo, and Cabo San Lucas) ; southern Sonora (rarely Alamos) ; and Nuevo Le4Sn (rarely Monterrey). East to Nuevo Le6n (Monterrey) ; Guatenlala (Lake Atitl~n, Cob~n, Patulul, and Duefias); Costa Rica (San Jos6, Barranca, Buenos Aires); PanamA (VolcAn de Chiriquf and Col6n) ; and northern Colombia (Antio~ quia, Santa Elena, and Bogot~). South to Colombia (BogotA); El Salvador (Volc~n de San Miguel, Volc~n de Conchagua, and Volc~n de Santa Ana); and Oaxaca (Tehuantepec). West to Oaxaca (Tehuantepec); Michoac~n (Patamben and Zamora); Colima; Sinaloa (Mazatl~n and Escuinapa); and southern Baja California (La Paz).

Casual in northeastern British Columbia (Lower Liard Crossing) southwestern Manitoba (Aweme); southwestern North Dakota (Buffalo Springs Lake); eastern South Dakota (Aberdeen); Nebraska (Stapleton, North Platte, and Hastings); Kansas (Blue Rapids); and northwestern Texas (Gainesville).

The range as outlined is for the entire species, of which two subspecies are recognized. The northern MacGillivray’s warbler (Opororn~s toimiei tolmiei) is found from southern Alaska, British Columbia, north-central Alberta, southwestern Saskatchewan, and southwestern South Dakota south to southern Baj a California, throughout Mexico (except the Yucatan Peninsula), Guatemala, El Salvador, Costa Rica, Panama, and northern Colombia; the southern MacGillivray’s warbler (Oporornis tolmiei mo’nticola) is found from northeastern California, southern Oregon, southern Idaho, southern Wyommg, northern and central Nevada, central Arizona, and through central Colorado to south-central New Mexico south to Colima, Michoac~n, Morelos and Guatemala.

Migration: Late dates of spring departure are: El Salvador: Volc~n do Santa Ana, May 15. Guatemala: above TecpAn, May 10. Tamaulipas: G6mez Farias region, May 3. Sonora: Rancho Ia Arizona, May 22.

Early dates of spring arrival are: Sonora: Chinobampo, March 7. Texas: El Paso, April 21; Los Fresnos, Cameron County, May 4. Oklahoma: Cheyenne, May 13. Nebraska: North Platte and Hastings, May 7. North Dakota: Wilton, May 22. Saskatchewan: Wiseton and Conquest, May 25. New Mexico: Fort Bayard, April 1. Arizona: Tucson, March 23. Colorado: Denver, May 1. Utah: Pine Valley, Washington County, May 11. Wyoming: Torrington, May 7. Idaho: Meridian, May 5. Montana: Fortine, May 11. Alberta: Onoway and Waterton Lakes Park, May 25. California: Berkeley, April 2 (average for 18 years in San Francisco Bay region, April 13). Nevada: Pioche, May 12. Oregon: Salem, April 17. Washington: Shelton, April 15; Walla Walla, April 28. British Columbia: Courtenay, Vancouver Island, April 14. Alaska: Wrangell, June 9.

Late dates of fall departure are: Alaska: Point Barrow, September 12. British Columbia: Okanagan Landing, October 2. Washington: Kamiak Butte, Whitman County, September 27. Oregon: Eugene area, November 2; Multnomah County, October 12. Nevada: south end of Belted Range, Nye County, September 28. California: San Francisco Bay region, November 21; Los Angeles, October 24. Montana: Fortine, September 11. Idaho-Moscow area, September 30. Wyoming: Laramie, October 15 (average of 7 years, September 17). Utah: Boxelder County, September 19. Colorado: Weldon, October 20. Arizona: Keams Canyon, October 12. New Mexico: Apache, October 12. Saskatchewan: Last Mountain Lake, August 25. Manitoba: Aweme, September 9. Oklahoma: Cimarron County, September 24. Texas: El Paso, October 8. Mexico: Sonora, Cajon Bonito Creek, September 28.

Early dates of fall arrival are: Utah: Salt Lake City, August 10. Arizona: Tucson, August 6. New Mexico: Apache, August 3. OkIahoma: Cimarron County, August 16. Texas: El Paso County, August 21. Mexico: Sonora, Cerro Gallardo, August 14. Guatemala: Duefias, September 17. Costa Rica: San Jose, September 25.

Egg dates: California: 39 records, May 2 to July 7; 21 records, June 2 to 20, indicating the height of the season.

Washington: 42 records, May 29 to June 22; 23 records, June 1 to 10 (Harris).

SOUTHERN MacGILLIVRAY’S WARBLER
OPORORNIS TOLMIEI MONTICOLA Phillips
This race was named by Dr. Allan R. Phillips (1947) and described as having the tail the “relatively longest” of the species; the “color dull, differing from 0. t. tolmiei in darker and grayer (less yellowish) green upper parts and paler and greener (less orange) yellow under parts. The difference in color of the under parts is less constant in fall females of unknown age, perhaps due to variation with age and to erroneous sexing of some young birds.”

He says that it breeds “in dense deciduous brush of the Canadian Zone from southeastern Oregon (Steens and Mahogany Mts.) and southwestern Wyoming (Ft. Bridger and Steamboat Mt.) south to central Arizona (White and San Francisco Mts.) and central New Mexico (Alto).”

It evidently winters in Mexico and Guatemala.