1915 BIRDS OF CALIFORNIA 91 
bara Islands. Occurs sparingly east of the Sierra Nevada in the Death Valley 
region and north through Owens Valley to Bishop Creek, Inyo County (A. K. 
Fisher, N. Amer. Fauna no. 7, 1893, p. 63). 
273 (459) Nuttallornis borealis (Swainson) 
OLIVE-SIDED FLYCATCHER 
Synonyms—Oontopus borealis; Tyrannus borealis; Tyrannus coopert. 
Status—Common summer visitant to the Transition and Canadian zones in 
the Sierras and Coast Ranges, the whole length of the state. Southeasternmost 
breeding record, Cuyamaca Mountains, San Diego County (Bendire, Life Hist., 
mt, 1895, p. 282); northeasternmost, Warner Mountains, Modoe County (Mus. 
Vert. Zool.), though otherwise not recorded east of the Sierrras except as a 
migrant. Breeds west to the coast from Monterey County northward. Ordina- 
rily confined in summer to areas well above the lower edge of Transition; but 
noted locally during that season in country that is dominantly high Upper Sono- 
ran, at Stanford University (W. K. Fisher, Condor, v1, 1904, p. 108), and at 
Berkeley (J. Grinnell, Condor, xv1, 1914, p. 32), where planted coniferous trees 
form extensive groves, thus introducing Transition zone conditions. The species 
occurs rather widely in migration, through the valleys both east and west of the 
Sierran divide, casually to the Farallon Islands (Dawson, Condor, xin, 1911, p. 
180). 
274 (462) Myiochanes richardsoni richardsoni (Swainson) 
Western Woop Pewrr 
Synonyms—Contopus richardsoni; Horizopus richardsoni; Tyrannula 
virens; Contopus virens var. richardsoni; Contopus richardsoni saturatus; 
Short-legged Pewee. 
Status—Common summer visitant to Upper Sonoran, Transition and Cana- 
dian almost wherever these zones oceur. Most abundant in Transition along the 
main mountain ranges; fewer in the more arid regions east of the Sierras, and 
in the northern humid coast belt. Widely distributed during migration over the 
low country both east and west of the Sierras, even to the Santa Barbara and 
Farallon islands. 
275 (464) Empidonax difficilis difficilis Baird 
WESTERN FLYCATCHER 
Synonyms—Empidonax flaviventris; Empidonax flaviventris difficilis; 
Empidonar cineritius; Empidonax difficilis cineritius; Empidonax insulicola; 
Island Flycatcher; San Lucas Flycatcher; Western Yellow-bellied Flycatcher. 
Status—Common summer visitant to portions of the Upper Sonoran and 
Transition zones the whole length of the state west of the Sierran divide; also in 
the Warner Mountains, Modoe County (Mus. Vert. Zool.). Occurs almost uni- 
versally throughout the state during migration. Breeds most abundantly in cer- 
tain foothill localities in the San Diegan district and in the southern humid 
coast belt including the San Francisco Bay region, but more sparingly along 
