Grace’s Warbler

The Grace’s Warbler has bluish-gray upperparts, a yellow throat and breast, a white belly with black streaking on the flanks, a yellow line above the eye, and two white wing bars.

The sexes are similar, though males are darker above.  Length: 5 in.  Wingspan: 8 in.

Photograph © Greg Lavaty.

The sexes are similar, though females are paler above.

None.

Recently fledged young lack yellow and have indistinctly streaked underparts.

Grace’s Warblers inhabit mountainous pine and oak forests.

Grace’s Warblers eat insects.

Grace’s Warblers forage in branches, as well as by flying out from a perch to catch insects in midair.

Grace’s Warblers breed in parts of the southwestern U.S.  In winter, these birds migrate to Mexico and Central America where mostly resident populations are found. The population is not well measured.

The nests of Grace’s Warblers are difficult to find, and the species has not been very well studied.

Grace’s Warbler is one of the smallest warblers in North America.

Calls include a soft “chip”, while the song is an accelerating trill of chip notes.

The Grace’s Warbler’s nest is a cup of plant fibers and silk, and is lined with hair and feathers. It is placed high in a tree on a horizontal branch.

Number: Usually lay 3-4 eggs.
Color: Whitish with darker markings.

Incubation and fledging:
The young are thought to hatch at about 12 days, and leave the nest after an unknown period, though continuing to associate with 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 Grace’s Warbler – the common name and sub-species reflect the nomenclature in use at the time the description was written.

This pretty little warbler was discovered by Dr. Elliott Coues (1878) and named by him in honor of his sister and for whom, as he expresses it, “my affection and respect keep pace with my appreciation of true loveliness of character.” Of its discovery, he states: “While journeying through New Mexico, en route to Fort Whipple, Arizona, in July, 1864, I found Grace’s Warbler on the summit of Whipple’s Pass of the Rocky Mountains, not far from the old site of Fort Wingate, and secured the first specimen on the second of the month just named.” He afterwards found it to be “the most abundant bird of its kind, excepting Audubon’s Warbler,” in the pine forests on the mountains of Arizona, and says that Henshaw found it to be “one of the commonest of the summer Warblers in the White Mountains. * * * His observations confirm my own in regard to the pine-loving character of the birds; he found them almost invariably in coniferous forests, passing swiftly along the smaller branches of these tall trees, or darting into the air to capture passing insects; and even in August, when various families had united into small flocks, and were lingering in company with other insectivorous birds, before their departure for the South, their preference for their native pines was still evident.”

I found it fairly common in the upper reaches of Ramsey Canyon in the Huachuca Mountains of Arizona, among the tall, scattered yellow pines, at elevations between 0,000 and 7,000 feet, where a nest with young was found on June 4, 1922. Swarth (1904) found it more common there as a migrant than as a breeding bird and rather irregular in its abundance.

Grace’s warbler, now well-known as a summer resident in the mountains of southern Colorado, New Mexico, Arizona, Sonora, and Chihuahue, is apparently closely related to the yellow-throated warbler of the southern States and to Adelaide’s warbler of Puerto Rico; it has a slightly differentiated subspecies in Central America.

Nesting: What is probably the first authentic nest of Grace’s warbler to be reported was taken in Yavapai County, Ariz., on June 23, 1890, by H. Keays for H. P. Attwater. This nest is described by Samuel B. Ladd (1891) as “placed on limb of pine sixt.y feet from the ground. Nest very compact; outside diameter 3 in. by 1½ in. high; inside diameter 13/4 in. by 11/4 in. deep. The body of this nest is composed of horse-hair, strings and vegetable fibres. The most abundant vegetable material interwoven consists of the staminate catkins and bud scales of Quercus emoryi. There is also some wool, vegetable down, and insect webbing, in which are entangled the exuviac of some caterpiller. Attached on the outside was a small staminate cone of a species of Pinus. Nest well lined with feathers and horse-hair.”

0. W. Howard (1899) found two nests in Arizona; one nest was “placed deep down in the middle in a large bunch of pine needles and was entirely hidden from view.” The other he found “in a icd fir tree. It was placed in a thick bunch of leaves at the extremity of a limb about fifty feet from the ground.” A nest with four eggs, in t.he Doe Museum in Gainesville, Fla., taken by 0. C. Poling on May25, 1891, at 8,000 feet in the Huachuca Mountains, was built in a bunch of pine needles and cones at the end of a long branch of a red pine, 20 feet from the ground.

Eggs: From 3 to 4 eggs, apparently more often 3, make up the set for Grace’s warbler. They are ovate with a tendency toward elongate ovate, and are only slightly glossy. They are white or creamy white, finely speckled and spotted with “auburn,” “bay,” or “chestnut brown,” intermingled with “light brownish drab,” “deep brownish drab,” or “pale vinaceous drab.” The markings are concentrated at the large end, where they frequently form a distinct wreath, leaving the lower half of the egg immaculate. Occasionally eggs are speckled all over; and some are marked with blotches. Generally the drab spots are in the majority, when the fewer brown spots, which are often as dark as to appear almost black, are more prominent. The measurements of 38 eggs average 16.9 by 12.7 millimeters; the eggs showing the four extremes measure 18.2 by 13.1, 18.0 by 18.3, 14.8 by 12.7, and 15.4 by 11.7 millimeters (Harris).

Young: Nothing seems to have been published on incubation or on the development and care of the young.

Plumages: Ridgway (1902) describes the young male in first l)lllmage as “above plain grayish hair brown or drab-gray, the feathers ash gray beneath the surface; sides of head similar but rather paler; malar region, chin, and throat pale brownish gray, minutely and sparsely flecked with darker, the chest similar, but with rather large roundish spots of dusky; rest of under parts dull white streaked or spotted with dusky gray medially, dull grayish laterally.”

Swarth (1904) writes of the postjuvenal molt:

A young male taken July 13th is in the brown streaked plumage, but yellow feathers are beginning to appear along the median line of the throat and upper breast, and the yellow superciliary stripe is a!so beginning to show. Another, a little older, has the streaks of the lower parts restricted to the sides and flanks, and the yellow markings nearly perfect. A male taken on July 80th, which has just discarded the juvenile for the winter plumage, differs from the autumnal adults in having the white of the under parts more strongly tinged with buff; and whereas the adult has the back decidedly streaked, though the markings are overcast by the brownish edgings to the feathers, in the juvenile these markings are but imperfectly indicated.

Apparently, the nuptial plumage is assumed by wear alone, for no available specimens show any signs of prenuptial niolt and both young birds and adults in the fall are much like the spring birds, but browner and with themarkings obscured by brownish tips that probably wear away before spring.

Young birds and females have duller colors than the adult males and are browner in the fall than in the spring. Adults doubtless have a complete postnuptial molt in late summer.

Behavior: G race’s warbler is a bird of the pines, spending most of its’ time in the towering tops of the tallest trees. It is sometimes seen in other conifers such as hemlocks and spruces, btit very seldom on or even near the ground. Dr. Wetmore (1920) says: “Usually they were found in the tops of the Yellow Pines where they worked about rather leisurely, exploring the smaller limbs and at short intervals pausing to sing. * * * Occasionally one was found working about through the oak undergrowth at times coming down almost to the ground. The flight was tindulating and rather quick and jerky.”

Dr. Coues (1878) writes: “They are seen coursing among the branchlets, skipping at apparent random through the endless intracacies of the foliage, hovering momentarily about the terminal bunches of needles, and then dashing far out into clear space, to capture the passing insect with a dexterous twist and turn. So the season passes, till the young are on wing, when the different families, still with bonds unbroken, ramble at leisure through the woods, the young birds timid and feeble at first, venturing shorter flights than their parents, who seem absorbed in solicrtude for their welfare, and attend them most sedulously, till they are quite able to shift for themselves.”

We found Grace’s warbler to be an active, restless species. We could often locate one by its song coming from lofty top of some tall pine, but before we could see its diminutive form, we would hear its song coming from some distant tree farther up the mountain side; and so we would follow the little songster from tree to tree, seldom getting more than a fleeting glimpse of it. At times, however, when it was more interested in feeding than in singing, we could see it quietly gleaning its insect food along the smaller branches and twigs after the manner of the pine warbler. We never saw it on or near the ground.

Voice: Dr. Wetmore (1920) says that the song of Grace’s warbler, as heard by him at Lake Burford, N. Mex., “was a rapid repetition of notes somewhat reminiscent of the efforts of the Chipping Sparrow, but with the notes evenly spaced, not blurred at the end, and closing abruptly, so that the last syllable was as strongly accented as any of the others. It resembled the syllables chip chip chip chip chip given in a loud tone.”

Dr. Walter P. Taylor has sent me some notes on the song, which he calls “rather a modest utterance conspicuously lacking in strength. Song, t8eet t8eet tseet taeet zeelde zeet. A better rendering is tsew t8e?w tsew t8elJJ tsew tsee tsee tsee tsee tseeeip! The song has something of a yellow warbler quality. I find it extremely hard to put down on paper anything that remotely resembles it.” Again he writes it “tckew tchew tchew, more slowly uttered, followed by tsip taip tsip t8p taip, rapidly repeated.”

Field marks: Grace’s is one of the smallest of our wood warblers, a tiny bird. It shows a striking resemblance to the yellow-throated warbler, but it is much smaller, has no black in the cheeks, and it has a yellow rather than a white mark below the eye. The adult male in spring is light bluish gray above, marked on the head and back with black spots, with a bright yellow throat, two white wing bars, and much white in the tail. Females, young birds, and males in the fall are similar but browner.

DISTRIBUTION
Range: Southwestern United States to central Mexico.

Breeding range: Grace’s warbler breeds north to southerii Utah (Zion National Park); southwestern Colorado (Fort Lewis and Pagosa Springs); and central northern New Mexico (Tres Piedras; possibly Sierra Grande). East to central New Mexico (Tres Piedras and Mesa Yegua) ; western Texas (Guadalupe Mountains); and northwestern Chihuahua (Colonia Garcia). South to northwestern Chihuahua (Colonia Garcia) and southeastern Sonora (Rancho Santa Barbara). West to western Sonora (Rancho Santa Barbara, Moctezuma, and Nogales); eastern central and western Arizona (Huachuca Mountains, Tucson, Fort Whipple, Hualpai Mountains, and Mount Trumble) ; and southwestern Utah (Zion National Park).

Winter range: In winter Grace’s warbler seems to be confined to a small area in central western Mexico, from central Jalisco (Bolafios) southeast to east central Michoac~n (Patamb~n and Patzcuaro); and west to south central Jalisco (Zapotitl~tn); occasional north to northern Nayarit (Santa Teresa).

Migration: Very little information is available regarding the migratory movements of Grace’s warbler. Dates of spring arrival are: Sonora: Mina Abundancia, April 11. New Mexico: Silver City, April 20. Arizona: Santa Rita Mountains, March 15. The latest date of one recorded at Albuquerque, New Mexico, is September 7. A resident race occurs in Central America.

Egg dates: Arizona : 9 records, May 3 to June 27; 5 records, May 30 to June 8, indicating the height of the season.

New Mexico: 2 records, May 22 and June 13 (Harris).