274 REPORT OF NATIONAL MUSEUM, 1890. 



ming uoise. He u never saw any other bird where the force of its wings 

 appeared (as in a butterfly) so powerful in proportion to the weight of 

 its body. When hovering by a flower, its tail is constantly expanded 

 and shut like a fan, the body being kept in a nearly vertical position." 

 Mr. Darwin does not say whether any sound is produced by the wings 

 of this species ; but I am informed by Mr. W. E. Satford, U. S. Navy, 

 who has frequently observed them, that the flight of the Giant flurn- 

 ming Bird is as noiseless as that of a butterfly. 



Those Humming Birds, with elongated spatule-tipped tail feathers 

 are "to a degree peculiar in their flight, although the motion of the 

 wings themselves is essentially the same as in ordinary kinds. The late 

 Mr. Dyson iuformed Mr. Gould that the flight of these Racquet-tailed 

 Hummers is very peculiar, and that their appearance in the air is most 

 singular; the tail being not only constantly opened and shut, but the 

 spatules always in motion, particularly when the bird is poising over a 

 flower. 



Although the muffled buzzing or humming uoise, which has given this 

 family of birds its distinctive name is the sound usually accompany- 

 ing the flight of Humming Birds, the males of some species accompany 

 their flight with a most remarkable noise, of an entirely different char- 

 acter. While among the mountains of Utah, in 18G9, the writer was 

 for along time mystified by a shrill screeching noise, something like that 

 produced by a rapidly revolving circular saw when rubbed by a splin- 

 ter. This noise was evidently in the air, but I could not discover its 

 origin, until I discovered a Humming Bird passing through the air over- 

 head in a curious undulating line of flight. I afterwards heard the 

 same sound produced by males of the same species (the Broad-tailed 

 Humming Bird, tSelaspliorns platycercus), when they were driving other 

 birds away from the vicinity of their nests. At such times they would 

 ascend almost perpendicularly to a considerable height, and then de- 

 scend with the quickness of a flash at the object of their animosity, 

 which was perhaps more frightened or annoyed by the accompanying 

 noise than by the attack itself. 



Mr. F. Stephens,* calls this the "courtship song," but from the cir. 

 cuinstauce that, in the Broad-tailed Humming Bird at least, it is often 

 produced by solitary individuals while wending their way between dis- 

 tant points, I hardly think it can properly be so considered. Writing 

 of Costa's Humming Bird (Calypte costw), he says: 



The female is sitting on a twig in a low bush, not on an exposed twig as is often 

 tbe case when she is merely resting, but when the male begins she goes farther in, 

 as if she feared that he really intended mischief, while he rises high in the air, and, 

 with a headlong swoop, comes down, passing her, and turning with a sharp curve 

 as near her as is possible mounts on high to repeat the maneuver again and again. 

 A shrill whistle is heard as he begins to descend, starting low and becoming louder 

 and louder, until as be passes her it becomes a shriek w T hich is plainly audible for a 

 distance of 100 yards or more. As he mounts again it dies away only to be repeated 



* Bulletin of the Ridgway Ornithological Club of Chicago, No. 2, 1887, pp. 44, 45. 



