CALIFORNIA LINNET. Carpodacus mexicanus frontalis (Say)

Field characters.—Size of a Junco (length 5-1/2 inches); only slightly smaller than California Purple Finch; tail practically square-ended (fig. 50b). Wings and tail brown with no white or yellow markings. Male: Head (except crown), whole fore part of body, and rump, bright red; belly dull whitish, streaked sharply with brown. Female: Brown, entirely lacking either red or any tinge of green; whole under surface of body streaked with brown on a clayey white ground. (See pl. 7e, f.) Flight markedly undulating. Voice: Male has a prolonged and varied, bubbling song, to be heard at almost any time of year except in late summer and fall; both sexes utter a pleasing call note which has a rising inflection, che-eep.

Occurrence.—Common resident of lowlands and foothills (Lower and Upper Sonoran zones) on west side of Sierra Nevada, from Snelling and Lagrange eastward to 6 miles east of Coulterville, to El Portal, and to Mount Bullion. Rare in Yosemite Valley. Common east of the mountains, in vicinity of Mono Lake. Usually in flocks except during nesting season, when in attentive pairs or family groups.

The California Linnet or House Finch is, in California, the lowland counterpart of the purple finches. Because of its greater abundance and its occurrence in settled districts it is more widely known than its mountain-dwelling relatives. In the Yosemite section it is abundant in the western valleys and foothills and is found also in smaller numbers beyond the mountains, about Mono Lake. In spring when attending to the rearing of their broods the birds are to be seen in pairs or family parties, but later in the year after the young are abroad, adults and immatures join in flocks often of large size and forage together in fields, gardens, and orchards as well as on various sorts of wild land where seeds of such plants as sunflower and thistle abound.

The red coloration of the male linnet is of a brighter hue than that of the male of either of the purple finches, but this color does not in the present species cover the whole crown of the head. The under part of the male linnet's body is streaked, while in the purple finches it is plain. (See pl. 7.) The female linnet lacks any tint of green, it is narrowly streaked beneath, and the ground color of the lower surface is tinged with clay color or ocher. From either of the purple finches the linnet may be distinguished from beneath by its square-ended instead of emarginate tail (fig. 50).

It is a well-known fact that the red areas on the male linnet in fall are dull, and that the color gradually increases in brilliancy as the season progresses. Attempts to explain this transition as a change of color without molt involved much speculation on the part of naturalists two or three decades ago. It is now known that the change is entirely the result of the mechanical process of wear. In new plumage the red feathers are tipped and faced with minute structural elements which are white. As these parts are gradually worn off, the red is unmasked and thereby the bird increases in brilliancy. Thus the male linnets when foraging in the mixed flocks during fall and winter are dull-hued, pinkish rather than bright red. By the time that singing and courting are commenced in earnest, in early spring, the birds have become much more brilliant in hue, and so they make more of a display when they sue animatedly for the attention of the dull plumaged females.

Linnets, like purple finches, when frightened usually seek safety in flight rather than in dodging into the protection of trees or brush as many sparrows are wont to do. If a flock of linnets is come upon suddenly, while feeding in a weed patch or on the ground, they get up quickly with an audible whirring of wings and make rapidly off in ascending course. The flock is usually dense when it first rises. Then it opens out and the individuality of the members is expressed as each pursues its own undulating course. Linnets, more perhaps than any other of the finches, are accustomed to strike out into the open, mounting high into the sky and circling for a time, before descending again.

The song of the male linnet is heard off and on through the greater part of the year. After the annual molt begins, in late summer, singing is indulged in sparingly and the birds usually remain relatively quiet until some protracted warm spell during the late winter, or until the first days of actual spring. From then on, their voices resound, in favorable places, from early dawn until late dusk. During the courting season they are as apt to pour forth their melodies while in flight high overhead as when perched.

After the couples have become established, the male and female of each pair stay close together, both when perched or when in flight, and when alone or with other pairs. In flight, the male usually keeps a little behind and to one side of the female, and when foraging he is quick to follow any changes in her location. After she begins the work of incubation he is wont to post himself on a perch close to the nest, where he is to be seen and heard much of the time.

Linnets build their nests in a wide variety of situations. Near Lagrange, on May 6, 1919, a nest was found on the up-stream side of a pile of drift close beside the Tuolumne River. It was ensconced in a natural niche in the mass of drift about 5 feet above the ground. Near Coulterville, on May 10, 1919, an incomplete nest was found about 8 feet above the ground in a slender blue oak. At Pleasant Valley, on May 23, 1915, a nest with two fresh eggs was seen 5 feet above the ground in a small blue oak. At Snelling on May 28, 1915, a nest with 5 fresh eggs was found in an old cliff swallow's nest on the wall of a gully and only 61 inches above, the bed of the wash (pl. 47b). At Smith Creek, east of Coulterville, on June 5, 1915, a nest with 2 young birds in it was seen 5 feet 4 inches above the ground in a young yellow pine.

The nests are simple affairs, of rather loose construction, composed of plant stems and fibers of various kinds, and often lined with horsehair. A typical nest measured externally 4 inches in diameter and 2-1/2 inches deep. Four is probably the usual complement of eggs, although we found one nest with 5 eggs and another held but 2 young birds. The nesting season probably begins in April, as on May 26, 1915, some young of the year were already out of the nest. Two days later a set of fresh eggs was seen.

A rather unusual case was that of partnership nesting, noted at Dudley, 6 miles east of Coulterville, on July 14, 1920, where two nests had been built on one beam inside a barn. The nests were placed so close to one another that the constituent materials were interwoven on the adjacent sides. The centers of the two nests were but 4-1/2 inches apart. Each nest contained 4 fresh eggs, and so far as could be seen the householders were deporting themselves with model comity.

Linnets seem to find enough forage in the lowlands to sustain them throughout the year, as they do not ordinarily invade the high mountains in late summer and fall after the manner of some insect-eating birds. A probably casual occurrence is that in the vicinity of Le Conte Lodge in Yosemite Valley, August 19, 1917 (Mailliard, 1918, p. 15). Those linnets which summer on the Mono Lake side of the mountains probably leave that region in the winter season. Our earliest and latest records of birds actually observed there are, respectively, May 21 (1916) and September 20 (1915), both near the shore of Mono Lake. One of the surprising discoveries made on Paoha Island in Mono Lake was a colony of about 30 linnets which was established there for the summer at the time of Mr. Dixon's visit on May 27, 1916. Nests were seen in and about the old buildings on the island.

Several linnets shot on the Dudley Ranch, along Smith Creek east of Coulterville, on July 23, 1920, had been eating the then green and sticky fruits of the mountain lilac (Ceanothus integerrimus). A week or two later, as the apples in the ranch orchard began to ripen, linnets, young and old, congregated there. The birds were expert at keeping quiet amid the thick foliage, where they were taking generous toll of the fruit; the gullets of those that were shot were full of 'apple sauce.' Shooting seemed to avail little against the tide of incoming birds, which seemed to sense the feast from afar. Those persons who decry the killing of birds on the plea that they are, at least part of the year, in one locality or another, of economic importance (by destroying weed seeds, in the case of the linnet) should put themselves in the place of the mountain rancher at harvest time, when hungry young birds continually pour in from the surrounding wild lands and fatten on his crops.