GREEN, GREENISH GRAY, AND OLIVE 417 
small a shell. During the first week they double in 
weight every twenty-four hours, and at the end of four 
days, although still blind and naked, weigh as much as 
acanary. Most of the food is given them by regurgita- 
tion so long as they remain in the nest. They are 
slow in developing, and do not fly until nearly four 
weeks old. 
PLUMAGE GREEN, GREENISH GRAY, AND OLIVE 
429. BLACK-CHINNED HUMMINGBIRD. — Trochilus 
alexandri. 
Famity: The Hummingbirds, 
Length : Male 3.30-3.75 ; female 3.90-4.10. 
Adult Male: Upper parts metallic greenish ; under parts whitish, washed 
with green on the sides ; chin and throat velvety black, bordered be- 
low by a broad band, metallic purple, green, and blue. 
Adult Female: Upper parts bronzy; under parts light grayish; tail 
much rounded, with middle feathers green, next two tipped with 
black, next three tipped with white. 
Young: Similar to adult female, but feathers of the upper parts mar- 
gined with buffy. 
Geographical Distribution: Western United States, east to Rocky 
Mountains, south over table-lands of Mexico. 
Breeding Range: From British Columbia south to Lower California, and 
from the Pacific to the Rocky Mountains, chiefly in the upper Sonoran 
zone, 
Breeding Season: May 1 to August 15. 
Nest: In trees or bushes, 4 to 7 feet from the ground; of buffy plant 
down covered with spider’s web. 
Eggs: 2 or 3; white. Size 0.50 0.32. 
In some localities the Black-chinned Hummingbird is 
known as the Purple-throated Hummer, and this seems 
to describe him about as well as his more common name, 
for just below the black chin is a band of iridescent 
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