GREEN-TAILED TOWHEE. Oberholseria chlorura (Audubon)

Field characters.—Size and habits recalling both Fox Sparrow and Spurred Towhee, but coloration and voice very different from either. Crown of head bright chestnut; throat abruptly pure white, surrounded by uniform light gray of neck and breast; wings and tail dull yellowish green; back greenish brown, not streaked; no white spots on wings or tail, or dark spots on breast. (See pl. 48b). Young streaked. Seeks safety under brush rather than by flight. Voice: Song of male, a wheezy sup-se-tew'-see-si-se, or eet-ter-te-te-te-si-si-si-seur; call note of both sexes a cat-like me-u or zew, or a more prolonged mee a-yew.

Occurrence.—Moderately common summer visitant to Canadian Zone on both slopes of the Sierra Nevada, and to Transition Zone east of the mountains. Observed at Crane Flat and Chinquapin and thence eastward to Porcupine Flat and Mono Meadow; and again, beyond the mountains, near Walker Lake, Williams Butte, at Mono Mills, and at Mono Lake Post Office. Seen in Yosemite Valley October 2, 1915, September 5, 1917, May 15 to 23, 1919, and June 23, 1920. Ranges more widely after nesting season; for example, noted at 10,700 feet on Mount Florence, August 21, 1915. Nests in brush thickets, and forages near or beneath these. In pairs during nesting season, solitary at other times.

The Canadian Zone thickets of snowbush, chinquapin, and green manzanita which harbor the Mariposa Fox Sparrow during the summer months are at the same time often frequented by another big towhee-like sparrow, but one of altogether different coloration and voice. This is the Green-tailed Towhee. It wears a very unusual pattern of coloration, distinguishing it from all other birds in the Sierras, and its call note is as distinctive as its plumage. The Green-tailed Towhee is not so abundant as the fox sparrow on the west slope of the mountains; our censuses there show about one individual of the former to four of the latter. On the east slope, however, the Green-tailed Towhee is found in many places to the exclusion of the fox sparrow; in fact, the former seems to be inherently a Great Basin product, along with the sagebrush and sage thrasher, and its occurrence to the westward is in the nature of a spilling over on the extreme margin of its geographic range.

The combination of conical bill, long tail, short wings, and stout legs and feet, proclaim the Green-tailed Towhee to be adapted for foraging beneath brush patches. (See pl. 48b). And that is exactly the manner in which it gains its livelihood. For safety it depends upon dodging into the recesses of the thickets, its short wings and long tail being suited to this means of escape.

Nesting with the Green-tailed Towhee begins about the middle of May, and from then until the end of July the birds are busy with family duties. Upon our arrival at Chinquapin on May 19, 1919, we found the birds in pairs with the males in full song, and at Tamarack Flat, on May 25, 1919, two completed nests were found, one of which contained one fresh egg and the other two. The nesting season must be somewhat protracted, for on June 21 (1915) at Mono Meadow a bird was observed with nesting material in her bill, although she was seen to fluff her feathers and shake herself as though she had already been engaged in the confining duty of incubation. East of the Sierras, at Mono Lake Post Office, on June 30, 1916, an adult was seen carrying food to young. The young, which are narrowly streaked like the young of the White-crowned Sparrow, but which have greenish wings and tail, are much in evidence toward the end of July, when the up-mountain scattering which follows the breeding season begins.

In 1919 three Green-tailed Towhees were seen in Yosemite Valley between May 15 and 23, and two of these (males, for they were singing) acted as if they were located for the season. The headquarters of these two were in chokecherry thickets near Redwood Lane, while the third individual was seen on two occasions near Stoneman Bridge. The species was reported by residents of the Valley to have nested there in 1918, but of this there was no conclusive proof. A singing male was present in Sequoia Lane in the Valley on June 23, 1920.

A typical nest found near Tamarack Flat on May 25, 1919, was 620 millimeters above the ground at the rim, and was situated in a nearly upright spray of snow bush (Ceanothus cordutatus) which stood out in the center of a large patch of the same plant. (See pl. 49a). The nest was thick walled and the cavity measured 67 millimeters across by 40 millimeters deep. The basal portion was of long slender branching fir twigs, well interlaced. Then came a middle layer of weathered pine needles and fine plant stems, and inside of this was a smooth lining of long horse tail or mane hairs and fine rootlets. The one fresh egg was pale greenish white in ground color and was marked, chiefly at the larger end, with minute spots of reddish brown. Four eggs is the usual complement. The other nest found was similar in all respects, save that its height above the ground was greater, 700 millimeters to the rim. The nest of this species is much more compactly formed than that of the Mariposa Fox Sparrow.

During the courting season the male Green-tailed Towhee sings at frequent intervals, although on the whole somewhat less often than the male fox sparrow. For singing the bird mounts to the topmost twig of his selected thicket and there says in rapid wheezy sequence, sup-se-tew'-si-se, or eet-ter-te-te-te-si-si-si-seur (according to the transcriptions of two different observers). Individual syllables may be added or dropped, but the general plan of the song remains about the same. The song is buzzy, distinctly like that of the Western Lark Sparrow, and not so much like the impressively clear lay of the fox sparrow. Between songs the cat-call is given at irregular intervals, and it is frequently uttered when the bird is disturbed or excited. Thus when the two nests mentioned above were being examined, the owners remained in the vicinity, at a distance of 30 or 40 feet, hopping about on the ground, exhibiting some concern, and voicing a kitten-like mew-weé.

East of the Sierras in the fall months the number of Green-tailed Towhees seems to be augmented over and above the normal seasonal increase by the appearance of migrants. When trapping for mammals was being carried on in the sagebrush near Williams Butte several of these towhees, attracted by the rolled oats placed on the traps as bait, fell undesired victims.

We have no data as to the time of arrival of the Green-tailed Towhees on the west side of the Sierras, nor is the route of their migration thither-ward known. On the east side, at Williams Butte, the first was seen in 1916 on May 6, after which the species was common. They were still there, at least as migrants, on September 22 (1915), when field work for the season was concluded in that locality. In Yosemite Valley on October 2, 1915, Green-tailed Towhees were frequenting the same thickets as the Golden-crowned Sparrows which had then just arrived from the north. The Green-tails were evidently on the verge of departing, as the last record for the season is of one seen near Glen Aulin on October 4, 1915, although field observations were continued on the west slope that year until late in November.

Mr. Joseph Mailliard (1918, p. 15), who visited Yosemite Valley from August 18 to September 29, 1917, states that he found no Green-tailed Towhees there until September 5; after that date they increased in numbers until, in favorable spots, such as the eastern end of Sequoia Lane, 8 or 10 could be seen within 200 yards.