WESTERN LARK SPARROW. Chondestes graminacus strigatus Swainson

Field characters.—Somewhat larger than Junco. Top of head and ear region chestnut, with a light stripe over crown and another over each eye; side of face white with three lines of black running backward from bill; tail rounded at end (often spread by the bird even when perched), blackish centrally, broadly bounded with white (fig. 54a); upper surface of body brown, streaked with black; lower surface gleaming white without markings other than a rounded black spot on breast. Voice: Song of male low-toned, long-continued, and much varied, but always with numerous buzzing or purring notes; both sexes utter a seep.

Occurrence.—Common resident of Upper Sonoran Zone on west slope of Sierra Nevada, ranging down into Lower Sonoran. Observed from Snelling and near Lagrange eastward to El Portal, and to 3 miles east of Coulterville. One pair seen in Yosemite Valley May 5 and 9, 1920 (C. W. Michael, MS). Also found east of the Sierras, around Mono Lake. Lives in semi-open country, in and about clearings and on dry grasslands with scattering trees or bushes. Seen usually in pairs in summer, in small companies in fall and winter.

The observant traveler who enters the Yosemite region over any of the highways which traverse the western foothills will be likely to see a sparrow with strikingly variegated plumage fly up from the roadside and perch on some fence or low tree, showing as it goes a fan-shaped tail that is dark centrally but broadly white at the end. And if, during the spring months, the same traveler should walk along any of these roadways or across the adjacent grassy oak-dotted hillsides he will probably hear the unique purring song of this bird, the Western Lark Sparrow.

Fig. 54. Tails of (a) Western Lark Sparrow and (b) Western Vesper Sparrow, natural size, showing differences in outline of partly spread tail and in distribution of the white.

Few of our sparrows wear such a distinctive pattern of coloration as the lark sparrow. The head is striped and recalls the coloration of the white-crowned sparrows, only in the lark sparrow the broad crown stripes are chestnut, separated and bordered by buffy white. There is a large patch of chestnut on the ear region of this bird; on the white face, extending backward from the bill on each side, are three lines of black. The otherwise white under surface has a single small rounded black spot low on the breast.

But the lark sparrow's most prominent feature is its tail. On each tail feather, excepting the middle pair, there is an extensive terminal spot of white and these spots increase in size from the center outward so that the outermost feather is almost entirely white. (See fig. 54a). The tail instead of being square-ended, as is that of most sparrows, is rounded; furthermore, it is a marked trait of the bird to spread the tail widely when it flies up from the ground and often even while perching quietly. The two sexes are alike; but the young, in juvenal dress, differ from the adults in having the throat and breast narrowly streaked with brownish black, and the pattern on the head less sharply contrasted.

The song of the male lark sparrow is not one that can be readily expressed in syllables; and so, beyond giving some of the general characteristics of the song, we must leave the reader to analyze it farther for himself. There are certain 'words' or 'phrases' and the stringing together of these, in varying sequence, constitutes the song. The latter is therefore not a set utterance such as is given by so many birds. One recognizes the lark sparrow's song by this irregular combination of soft notes, trills, and buzzing or purring notes, by its varying intensity, and by its long continuance. Few if any other local birds sing so incessantly as the lark sparrow. Many of its individual songs last for a minute or more, and during the late spring and early summer the male birds sing through most of the daylight hours. The song, even at best, lacks carrying power; to an auditor at a distance the song seems alternately to die away and to revive. At close range the song is heard to be continuous, but increases and decreases in loudness with every few notes. The lark sparrow often sings until late dusk and on several occasions we have heard it give a few bars long after nightfall.

By May the Western Lark Sparrows are busying themselves with nesting affairs and in June the young begin to appear abroad. At Snelling on May 27, 1915, an adult bird was seen carrying nesting material, and others behaved as though their headquarters were already well established. At Pleasant Valley on May 28, 1915, a nest with four eggs was discovered at the base of a yerba santa bush on a dry sun-heated hillside. Near the McCarthy ranch, 3 miles east of Coulterville, on June 2, 1915, another nest was found. This last nest had been placed on the ground on a gentle hillslope, in a spot sheltered by an accumulation of cones and branches from the yellow pines above. When first seen the nest held four eggs and as none were added by the following morning the set was believed to be complete. When this nest was again visited, on June 4, it was found to have been raided; one egg was gone and another lay broken outside the nest. Neither of the birds was seen on this last visit. The nature of the enemy was not determinable but it seemed likely that he had been frightened away before his meal was completed, as even the egg which was broken open still held some of its contents.

During the fall and winter months the lark sparrows gather into flocks which are usually small. But at El Portal, in December, at least 25 of the birds were seen together in a live oak standing out by itself in an open field. The species habitually forages upon the ground among grasses and other low vegetation; but when the individuals are alarmed they seek perches a few feet above the ground, whence, when further pressed, they fly off in an open course to a distance. They do not as a rule dive into the brush as do the White-crowns; nor do they run aside through the grass, as do the Savannahs.

Although these birds are permanent residents west of the mountains, they are probably only summer visitants in the elevated Mono Lake country. The first lark sparrow observed in the latter region was seen in the garden at Farrington's ranch, near Williams Butte, May 2 (1916). Others were encountered later the same month at this ranch, and also at Mono Lake Post Office.