Part 81

O. 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 red 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 the Doe Museum in Gainesville, Fla., taken by O. C. Poling on May 25, 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 =13.3=, =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 plumage 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 also 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 30th, 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 molt and both young birds and adults in the fall are much like the spring birds, but browner and with the markings 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.--Grace'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, but 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 undulating and rather quick and jerky."

Dr. Coues (1878) writes: "They are seen coursing among the branchlets, skipping at apparent random through the endless intricacies 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 solicitude 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, tseet tseet tseet tseet zeekle zeet. A better rendering is tsew tsew tsew tsew 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 "tchew tchew tchew, more slowly uttered, followed by tsip tsip tsip tsip tsip, 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 southern 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 García). =South= to northwestern Chihuahua (Colonia García) and southeastern Sonora (Rancho Santa Bárbara). =West= to western Sonora (Rancho Santa Bárbara, 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 (Bolaños) southeast to east central Michoacán (Patambán and Patzcuaro); and west to south central Jalisco (Zapotitlán); 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).

PLATES

Morristown, N. J. R. T. Peterson

BLACK-AND-WHITE WARBLER]

Maine, June 29, 1940 Eliot Porter

BLACK-AND-WHITE WARBLER, MALE]

Dennis, Mass. June 17, 1921 A. C. Bent

Johnson City, Tenn., May 10, 1942 B. P. Tyler