4.20 LAND BIRDS 
of the alexandri is well worth watching. Should you 
spy a male, swinging sidewise back and forth through 
the air, pendulum fashion, look for the dainty little lady 
on a twig about three feet in front of and a little above 
him. So absorbed is she in watching and he in perform- 
ing this curious aérial dance, that neither will notice 
you. Sometimes at its finish he will drop exhausted on 
any perch near and pay no further attention to her, but 
oftener | have seen her dart out into the sunlight as 
a signal for him to follow, and a merry chase through 
the blossoms followed. Once, as he sat resting after his 
graceful and apparently effortless swinging, the female 
flew toward him, lit daintily a few inches away, and 
quivered her iridescent wings. Instantly both birds 
were in the air apparently engaged in a mortal combat, 
and then he was back upon the perch like a flash of 
light, while she had disappeared. I have never seen the 
male Hummer assist at the nest building, and believe all 
the family cares are left to the female. She is larger 
and better equipped for labor than the brilliant little 
sprite who wooes her. | 
430. COSTA HUMMINGBIRD. — Calypte costae. 
Famiry: The Hummingbirds. 
Length: Male 2.75-3.20 ; female 3.55-3.70. 
Adult Male: Head and flaring ruff brilliantly burnished metallic ame- 
thyst violet, changing to blue and green ; rest of upper parts bronze- 
green ; under parts whitish ; belly washed with green. 
Adult Female: Upper parts bronzy green; under parts whitish ; throat 
spotted with metallic purple. 
Young: Similar to female, but duller and with feathers of the upper 
parts margined with buffy. 
