The Costa Hummer 
and was heard again later in the same night. * * Just at daylight on the 
morning of June 25th, before the shadow had risen out of Wild Rose 
Canon, a Costa hummingbird came and hovered within a foot of our 
camp fire, probably mistaking it from a distance for a bunch of buff 
flowers. It was observed on several occasions that any brightly colored 
object placed in a conspicuous position attracted the bird.” 
Bendire’s description of the nest is perfect: 1 “The nests of Costa’s 
Hummingbird do not compare favorably in architectural beauty with 
those of the preceding species [the Black-chinned Hummer]; the ma¬ 
terials used are not so thoroughly felted or quilted together, and the inner 
cup has, ordinarily, a rather slovenly appearance. It is externally com¬ 
posed of plant down or fine shreds of plant fiber; the outer walls are 
thatched more or less profusely, in different specimens before me, with 
bits of gray lichens, fine shreds of bark and small dry leaves, and these 
are securely fastened in place by spider webs and silk obtained from 
cocoons. The inside is lined with plant down, and occasionally with 
finely shredded plant fibers and small fluffy feathers. In some examples 
feathers are very prominent among the inner lining. An average speci¬ 
men measures 1 % inches in outer diameter by 1 inch in depth. The inner 
cup is about seven-eighths of an inch in diameter by one-half inch in depth.” 
The eggs, always two in number, are dull white in color, elongate 
elliptical in shape, and a little smaller than those of C. anna. Deposition 
occurs on succeeding days, and incubation, according to one authority, 2 3 
lasts for 14 to 16 days; according to another, 2 nine or ten days. This 
discrepancy is doubtless due in part to the irregularity with which different 
birds begin incubation. Some brood from the laying of the first egg. 
Others loaf around a day or so after the deposition of the second. Under 
favorable circumstances the young birds fly in from ten to fourteen 
days. 
The smallest bird’s egg on record is probably the one taken in 
a Costa’s nest by Nelson Carpenter at Escondido, June 11, 1905. This 
tiny atom, technically known as a “runt,” is about one-fourth the normal 
bulk and measures .29 x .21 (mm 7.37 x 5.33). No regrets for the present 
tense, please, for the little pearl contained no yolk and so never could 
have hummed. 
1 Life Histories, Vol. I., p. 205. 
2 R. H. Lawrence, quoted by Bendire, Life Histories, Vol. I., p. 203. 
3 J. B. Dixon: Condor, Vol. XIV., March, 1912, p. 76. 
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