272 REPORT OF NATIONAL MUSEUM, 1890. 



iug lior wiugH over the uest iu a seemiug ccstacy of delight, she rather lluttoriugly 

 turned arouud iu it, apparently without regard for its precious couteuts. 



There seemed to be oue never varying position wheu at rest, that fiicing the more 

 open part of the grove, the usual direction of approach being from behind, whereas 

 the flight from the nest was toward the clearer space in front. The sitting posture 

 was not one of absolute rest at any time, as the head was constantly in motion, so 

 that no approach could be made without her knowledge. The flight from the nest 

 seemed to be directly out of it, without auy preliminaries. The weather was warm, 

 yet she would remain on the nest from 15 to 20 minutes, and in no instance was away 

 more than 2 minutes while I had her under observation. The male frequently ap- 

 peared in the vicinity, but neither offered food nor even deigned to alight on the same 

 tree, yet birds which had a good claim in the neighborhood dared not approach very 

 close, as the combiued at tack of these active birds always proved so distasteful that 

 they invariably beat a hasty retreat,* 



MANNER OF FLIGHT. 



The extraorcliuary development of the pectoral muscles iu the Hum- 

 ming Birds and its purpose is made a special topic on pages 292, 293; but 

 a preliminary description of the motion imparted to the wings by these 

 powerful engines, if such tbey may be styled, and other particulars relat- 

 ing to the tlight of Bumming Birds, may be given here. As birds ditter 

 from all other animals in the possession of feathers, so do Humming 

 Birds differ from all other birds in their manner of flight, which, as 

 Mr. Gosse truly says, is entirely thai of an insect, especially a large 

 beetle or a bee. "To me," says Mr. Gould, "their actions appeared 

 unlike anything of the kind I had ever seen before, and strongly re- 

 minded me of a piece of machinery acted upon by a powerful spriug. 

 I was particularly struck by this peculiarity in the flight, as it was 

 exactly the opposite of what I expected. The bird does not usually 

 glide through the air with the quick, darting flight of a Swallow or 

 Swift, but continues tremulously moving its wings while passing from 

 flower to flower, or wheu taking a more distant flight over a high tree 

 or across a river. Wheu poised before any object this action is so 

 rapidly performed that it is impossible for the eye to follow each stroke, 

 and a hazy semicircle of indistinctness on each side of the bird is all that 

 is perceptible, t 



The wind produced by this rapid vibratiou of the wings is very con- 

 siderable, Mr. Salvin having noticed that while a Humming Bird which 

 had flown into a room was hovering over a large piece of wool, the 

 entire surface of the wool was violently agitated. 



Probably no one has ever observed the actions of Humming Birds 

 with greater care than Mr. Gould, whose enthusiastic interest in them 



•Edwin H. Eames, iu "The Auk," July, 1890, pp. 287,288. 



t According to Mr. Gosse ("Birds of Jamaica, " p. 133), the vibratiou of each wing 

 in the llellisuga minima reaches nearly or quite 180 degrees. In several of the plates 

 of the present work the artists have attempted to depict the appearance of the wings 

 during flight — the birds being represented in the attitude of poising over the nest. 

 (See plates xli and XLii. The appearance of the extended wings iu plates XLiii 

 and XLiv is, of course, incorrect, the object being to show the form of the wing and 

 arrangement of i ts feathers. ) 



