The Costa Hummer 
shreds, according to setting, and bound with cobwebs; less typically, compacted entirely 
of gray, weathered materials—sage-flower bracts and withered leaves—and lined 
coarsely with dark feathers; placed on dead weed or bush of desert or chaparral, or else 
at moderate height on descending branch of tree overlooking water. Eggs average 
12.2 x 7.9 (.48 x .31) (Bendire). Season: May-June; one brood. 
General Range. — Breeding in southern California, southern Utah, Arizona, 
southern New Mexico, and Lower California with its adjacent islands; wintering in 
Lower California and northwestern Mexico. 
Distribution in California. —Breeds chiefly in Lower Sonoran zone of southern 
California, north on the east side of the Sierras to the head of Owens Valley (Silver 
Creek, May 26, 1919), and in the interior portion of the southwestern coast ranges to 
southern Monterey County (San Ardo). Has occurred casually at Haywards (J. G. 
Cooper) and Oakland (McGregor) and, in winter, on the Colorado Desert (Grinnell). 
Breeds sparingly on the Santa Barbara Islands. 
Authorities.—Xantus (Atthis costae), Proc. Acad. Nat. Sci. Phila., 1859, p. 190 
(Ft. Tejon); Gault, Auk, vol. ii.. 1885, p. 309 (Arrowhead Springs, San Bernardino Co.); 
Lucas , Auk, vol. x., 1893, p. 311 (food); Grinnell, Condor, vol. xiv., 1912, p. 154 (Palm 
Springs, Feb.); Palmer, Condor, vol. xx., 1918, p. 114 (early hist.); Tyler, Condor, vol. 
xxii., 1920, p. 190 (San Joaquin Valley, breeding). 
NATURE has never staged a more thrilling form of entertainment 
than that provided by the male Costa Hummer for the delectation of his 
lady love. It is not alone that the intoxicated suitor hurls himself 
from the heights of heaven in vehement protestation of his love—all 
our hummers do that—but this one has evolved as an accompaniment a 
sound which I believe to be the very shrillest in the bird world, and one 
which is fairly terrifying in its intensity. This sound is generically 
like that produced by the Anna Hummer, but it is much more prolonged 
and more dramatic, more, in fact, like the shriek of a glancing bullet, 
or a bit of shrapnel. 
The lady, who has cultivated a taste for this sort of music, sits 
demurely upon a bit of sage not over two feet from the ground. The 
performer mounts dizzily to a height of 100 or 150 feet, then hurtles down 
at a speed several times that of mere gravity, intending thereby to make 
the parabolic climax the swiftest possible, and to vault back into the sky 
with the same impulse. The shriek begins when the hummer is about a 
quarter way down, gains in intensity until the climax of the curve is 
reached, and diminishes to the vanishing point as the momentum is 
spent. Talk of honeyed accents of love! This must sound like the very 
devil to the enamorata, coming, as it does, within six inches of her head. 
But she evidently enjoys it, for the performance is repeated again and 
again. Indeed, about twenty rounds appears to be the authorized 
number. And as a grand finale, the ethereal acrobat goes reeling off 
into space like a drunken comet, describing a zigzag course until 
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