172 PACIFIC COAST AVIFAUNA No. 11 
irregularly elsewhere throughout the state, even in suitable places on the deserts. 
The movements of the robin in winter appear to be governed largely by the 
varying supply of wild berries. 
538 (763) Ixoreus naevius naevius (Gmelin) 
Variep THRUSH 
Synonyms—Turdus naevius, part; Hesperocichla naevia, part; Geocichla 
naevia; Oregon Robin; Varied Robin; Western Robin, part. 
Status—Common winter visitant, chiefly to the humid coast belt and adja- 
cent areas south to Monterey County. This is the form prevalent in midwinter 
in the San Francisco Bay region. Summers sparingly in the Canadian zone of 
the northern humid coast belt: Lindsay and Redwood ereeks, Humboldt County 
(W. K. Fisher, Condor, m1, 1901, p. 91); Fair Oaks and Cuddeback, Humboldt 
County (Mus. Vert. Zool.). 
539 (763a) Ixoreus naevius meruloides (Swainson) 
NORTHERN VARIED THRUSH 
Synonyms—Twurdus naevius, part; Hesperocichla naevia, part. 
Status—Common but irregular winter visitant to the interior and southern 
portions of the state west of the desert divide, particularly the western foothills 
of the Sierras, and the San Diegan district south through Los Angeles County at 
least as far as Witch Creek, San Diego County (Willett, Pace. Coast. Avif. no. 7, 
1912, p. 109), and to San Clemente Island (Iimton, Condor, x, 1908, p. 86). 
Recorded interiorly to Walker Basin and Caliente, Kern County (Henshaw, Rep. 
Wheeler Surv., 1876, p. 226), and Yermo, San Bernardino County (Lamb, 
Condor, xiv, 1912, p. 40). Although this form breeds in Alaska to the north- 
ward of J. n. naevius, it winters in California south of that form. Several spe- 
cimens examined from central California are not with certainty identifiable with 
either one or the other of the forms. Individual variation evidently results in 
overlapping of characters in certain individuals, and there are also known to be 
true intergrades occurring in interlying areas of the summer habitat. 
540 (767+767b, part) Sialia mexicana occidentalis Townsend 
WESTERN BLUEBIRD 
Synonyms—Sialia mexicana; Sialia occidentalis; Sialia mexicana anabelae; 
Siaha mexicana bairdi; Anabel Bluebird; San Pedro Bluebird; Chestnut-backed 
Bluebird. 
Status—Common summer visitant to Transition and lower Canadian wher- 
ever these zones occur, nearly throughout the state. Least numerous in the north- 
ern humid coast belt; breeds also, but sparingly and locally, in Upper Sonoran, 
and in a few cases even in Lower Sonoran, as at Los Angeles (Myers, Condor, 
xiv, 1912, p. 221). Winters sparingly in Transition, and abundantly in Upper 
and Lower Sonoran, on both the desert and Pacific drainage slopes, south to the 
Mexican boundary. The recognition of a race anabelae from southern Califor- 
nia does not seem to be justified (see J. Grinnell and Swarth, Univ. Calif. Publ. 
Zool., x, 1913, pp. 316-319). 
