The Solitary Vireos 
A LITTLE UNCERTAIN 
CASSIN VIREO APPROACHING NEST 
Lake and Cape Breton Island south to Lower California and the mountains of Mexico; 
wintering from the Gulf States and Mexico south to Guatemala. 
Range of L. s. cassini. —The Pacific district, broadly defined; breeding in Tran¬ 
sition zone from central British Columbia, southwestern Alberta, and western Montana 
south through California and western Nevada to the San Pedro Martir Mountains; 
migrating through the Great Basin states to a winter home in Mexico. 
Distribution in California. —Common during migrations, practically through¬ 
out the State; remaining to breed only in the Transition zone and that chiefly in the 
Sierras and cognate ranges. Not common as a breeder in west central California 
nor in the humid coast strip. 
Authorities.—Gambel ( Vireo solitarius), Proc. Acad. Nat. Sci. Phila., iii., 
1847, 158 (Calif.); Xantus (Vireo cassinii), Proc. Acad. Nat. Sci. Phila., 1858, p. 117 
(orig. desc.; type locality Ft. Tejon); Barlow, Condor, vol. iii., 1901, p. 175 (Sierra 
Nevada; desc. nests, etc.); Beal, U. S. Dept. Agric., Biol. Surv. Bull., no. 30, 1907, 
p. 40 (food); Grinnell, Univ. Calif. Pub. Zool., vol. v., 1908, p. 109 (San Bernardino 
Mts.; occurrence, desc. nest and eggs, etc.). 
No. 115 b Plumbeous Vireo 
A. O. U. No. 629b. Lanivireo solitarius plumbeus (Coues). 
Description. — Adult: I.ikeL. 5. cassini, but the olivaceous and greenish yellow 
elements much reduced; scapulars entirely gray; the rump gray, tinged with olivaceous; 
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