HUMMINGBIEDS 357 



the vicinity of Chinquapin and Mono Meadow, where certain sun-facing 

 slopes were covered by heavy growths of wild currant. 



Adult males of all our species of hummingbirds have on their throats 

 a patch of iridescent feathers of greater or less extent, known as the 

 gorget, the display of which forms a part of the spring courting per- 

 formance. The distinctive peculiarities of the gorget as to color and 

 extent are set forth by us under the field characters for each species. 

 The males of most species of birds perform before the females during 

 the mating season, and in some of those species which have little or no 

 ability from a vocal standpoint, as is the ease with the hummingbirds, 

 the behavior is striking. The courting performance of the hummingbirds 

 takes the form of a special course of flight, distinctive for each species. 

 That of the Rufous is over a semicircular path in a vertical plane, and is 

 repeated many times in rapid succession ; that of the Anna is performed 

 in more deliberate manner over a high and narrow U-shaped course ; while 

 that of the Black-chinned is on a short horizontal line over which it moves 

 back and forth time after time. The nuptial flight of the Calliope is 

 somewhat like that of the Rufous, but less vigorous and not so extensive 

 or so continuous, two or three swoops being the rule. 



In the Calliope Hummingbird the individual feathers of the gorget 

 are long and lancet-like (pi. 46ft), and their lavender iridescence is set 

 forth in fine contrast by a white background. John Gould, the most 

 famous student of hummingbirds, named the bird appropriately, stellula, 

 meaning the little star. When the male Calliope is excited, as when in 

 chase of a rival, or in courting flight, these slender feathers are raised so 

 that they stand out prominently from the other feathers on the throat. 



The nuptial flight of the Calliope Hummingbird was seen by us only 

 a few times. In Yosemite Valley on May 31, 1915, a male and female 

 were seen in a patch of blossoming chokecherries. The male mounted into 

 the air a short distance and swooped down past the female, making a 

 slight metallic sound at the bottom of the arc. Flights of similar sort 

 were seen at Mono Meadow in mid-June but were not accompanied by 

 any sound audible to the human ear. Other male hummingbirds, notablj^ 

 the Anna, when thus performing, produce a loud metallic sound at the 

 moment of reaching the lowest point in the downward swing. 



Male hummingbirds are not known to take part in any of the duties 

 of nesting. In fact the location of a male seems to have no relation to 

 that of a female or of an occupied nest. Soon after the mating season the 

 males of the migratory species begin the southward migration; this is 

 evidently true of the Calliope. No male of this species was seen by us 

 after the end of June, 



