The Cassin Kingbird 
Distribution in California.—Summer resident of very local distribution in 
southern California, and west of the Sierran divide north to about Latitude 37 (Dos 
Palos, Merced Co., June 5, 1916, breeding). Winters sparingly in southern California 
and casually west to Santa Barbara; formerly to Santa Cruz (Auct. J. C. Cooper). 
Authorities.—Baird, Rep. Pac. R. R. Surv., vol. ix., 1858, p. 174 (Sacramento 
Valley; Ft. Tejon; Colorado R.); Bendire, Life Hist. N. Am. Birds, vol. ii., 1895, p. 249, 
pi. 1, figs. 18, 19 (eggs); Swarth, Pac. Coast Avifauna, no. 4, 1904, p. 20 (s. Ariz.; habits); 
Beal, L r . S. Dept. Agric., Biol. Surv. Bull., no. 44, 1912, p. 22 (food); Dawson, Condor, 
vol. xviii., 1916, p. 27 (range in Calif.). 
SOME FOLKS are twins. Such being the case, 
birds, we suppose, have no right to expect exemption 
from the common lot. The penalty of being a twin 
consists, of course, in being forever confused, mis- 
identified, and misunderstood. The similarity be¬ 
tween Tyrannus vociferans and T. verticalis is 
exceedingly close,—so close, in fact, that it is doubtful 
if a hundred people in California, apart from self- 
conscious and fully alert bird students, ever stopped 
to consider that they might be different. Yet 
the two species are perfectly distinct in plumage ■*"“* 
and in voice, and somewhat so in habit and 
disposition. These likenesses and differences, in two 
related species which are closely associated throughout 
much of the year, form one of the most fascinating 
problems of intimate bird study which California 
offers. 
The voice is the key to the difference: Cassin’s 
Kingbird says, Che bew', in a heavy, grumpy tone, 
whose last flick nevertheless cuts like a whip-lash— 
chebeeu'. This is generically similar, but specifically 
very different from the evenly accented, and more 
nearly placid ber'wick of the Western Kingbird. The 
note of greeting or of general alarm in Cassin is a 
breathless kuh day' kuh day' kuhday'; or, as I heard a 
female render it, kiddoo’ kiddoo’ kiddoo' kiddoo' 
kidduck'. For the rest Cassin is a rather more sober 
and a much more silent bird than is the volatile 
verticalis. Dr. Cooper 1 testifies that birds of this 
species are “less lively and quarrelsome in habit”; 
Taken in San Luis Obispo 
County 
Photo by the Author 
A PATRON OF WESTERN 
UNION 
1 Land Birds (of California), Vol. I., p. 314. 
859 
