Animal Life in the Yosemite
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THE BIRDS

NORTHERN VARIED THRUSH. Ixoreus naevius meruloides (Swainson)

Field characters.—Size of Robin and somewhat similar in coloration, but with a black, or (in female) slaty, band across chest, and a shorter tail. Upper surface slate-colored; under surface bright rusty brown (more orange than in Robin); conspicuous stripe of same color behind eye; also bars and spots of same on wing. In flight like Robin, but with a pale band showing lengthwise of each spread wing. Voice: Call note a single, not loud, deep, staccato chuck; song a slowly uttered series of weird syllables, successively on different pitches, now low, now high; each note intoned from one to three seconds: zurrrrr.

Occurrence.—A winter visitant to the western slope of the Sierras below the level of heavy snows. Common locally, reaching Yosemite Valley in late autumn (for example, October 28, 1915), and present in midwinter from south-facing slopes as high as 5000 feet (on Big Oak Flat road below Gentrys) down to the river-bottom thickets in vicinity of Snelling (January 7, 1915). Highest station: 7300 feet on ridge two miles north of Yosemite Point, three seen high in red firs October 30, 1915. Other stations of observation not mentioned beyond: Feliciana Mountain, October 28 to November 1, 1915; Gentrys, October 23, 1915 (earliest date); El Portal, December 9 and 17, 1914. Forages in scattered companies in chaparral or dense growths of small trees; seldom seen in the open.

Only the autumn or winter visitor to the Yosemite region will be likely to meet with the Northern Varied Thrush. Even when present, this bird is of such retiring disposition and quiet demeanor that it easily escapes detection. The writers have repeatedly approached within a few yards of birds on the ground or perched in bushes or trees, without realizing their presence until the birds took flight. One might think the bright markings of these birds would render them conspicuous; but, in fact, the broken pattern serves to obliterate their outlines against the leafy background.

Like its not distant relative, the Western Robin, the Varied Thrush (sometimes called Oregon Robin) feeds in the winter season chiefly on berries of various sorts, and its local occurrence and relative abundance is governed by the season's crop of these. Two or three of these birds seen among golden oaks near Camp Lost Arrow, November 13, seemed to be feeding on mistletoe berries. On the Big Oak Flat road, about 3 miles out of Yosemite Valley, on December 28, 1914, 8 or more Varied Thrushes were seen feeding on the sweetish berries of a manzanita (Arctostaphylos mariposa). On the Wawona road at Grouse Creek, November 26, 1914, two were apparently feeding on berries of the creek dogwood. In the Upper Sonoran foothill region, the Christmas berry or toyon (Heteromeles arbutifolia) furnishes a favorite food as long as the crop lasts.

In 1920 the species was first seen on October 24, and thereafter "large flocks" were observed on various dates throughout November and December (C. W. Michael, MS).



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Animal Life in the Yosemite
©1924, University of California Press
Museum of Vertebrate Zoology

grinnell/birds200.htm — 19-Jan-2006