270 TROCHILIDiE, HUMMINGBIRDS. 



the successive sliortoning of several outer primaries; and this bird, as is well known, 

 makes forrespoiidiiigly more rapid wiii>;-beats and vigorous, wliirring llight. In tho 

 Humniing-Uird the quickness of the wing-vibration readies the maximum; so rajiid is 

 it that the eye cannot follow the strokes, but merely perceives a film on each side of 

 the body. The lliglit of the bird is also the most rapid; frequently the eye cannot 

 follow the bird itself. It is ahnost needless to add, that the peculiar sound, from which 

 the family takes its English name, is not vocal, but j)roduced by the wings, just as it 

 is in the cases of so many insects. 



The tail is moderate, in most Hummers, but is too various in size and shape to he 

 concisely characterized here. It sometimes greatly exceeds the length of the body. 

 None of our r('i)reseutatives have any special developments "of this member. It always 

 has ten rectrices. The feet are small and short, and usually naked, though clothed in 

 some; the toes normal; the claws rather large, relatively, and sharp. The feet are 

 scarcely used for progression; the birds take to their wings for the briefest locomo- 

 tion. 



The birds are noted for their gorgeous coloring, duo in most part, and in the vast 

 majority of instances, to the iridescent glitter of their plumage; the metallic sheen is 

 specially noticeable upon the throat, forming the characteristic gorget of the male sex. 

 This is commonly wanting in the female, and she is also duller, usually, and otherwise 

 so different in color as to be frequently mistaken for a different species. The sexual 

 difference is sometimes so great, and affects such changes in size and shape of parts, 

 that even genera have been framed upon it, or the sexes of the same species referred 

 to different genera. Various greens, particularly of the golden series, are among the 

 commonest body-colors; purples and violet-blacks oftenesli tint the wings and tail; 

 the brilliant gorget changes hue in different lights, and here only, among birds, the 

 rainbow finds adequate material expression.* The crown is sometimes as brilliant as 

 the throat. Velvety-black and snowy-white occur. A part of the species are crested ; 

 others have the gorget prolonged into a ruff; many have white, cottony tufts upon the 

 flanks. 



The general interest that attaches to the Hummers causes them to be eagerly sought 

 after, and one good result of their search, to offset the lamentable wanton destruction 

 of the beautiful little creatures for mercenary ends, has been the unparalleled advance 

 of our knowledge of the species within comparatively few years. Now, we know at 

 least three hundred species, apparently valid, aside from the unnumbered nominal 

 ones tliat have been intj'oduced into the system. The family is confined to America, 

 and has its centre of abundance in the tropical parts of South America, esiiecially New 

 Granada, although some representatives are found from Alaska to Patagonia, and 

 others live on snowy Andean peaks. The species have been almost endlessly subdi- 

 vided into subfamilies and genera ; but, while the latter are undeniably many, perhaps 

 but two of the former may be recognized with certainty and entire propriety. One of 

 these, Pliaethoriiithince, embraces only about a tenth of the family, and is composed of 

 the duller-coloretl species, especially inhabitants of the dense forests of the Amazon. 

 The other, Troch'dinte, comprehends the great variety, and is the onlj' one represented 

 in North America, at least with the limitation of Phaiilhontithina; just alluded to. The 

 localization of many species is a singular fact in tlie history of the family; not a few 

 are strictly conliued, so far as is now known, to particular valleys or particular mount- 

 ain peaks, only a few miles in area. Others however, are widely dispersed, as our 

 Euby-throat and the western Rufous-backed Hummer, which reaches from Alaska into 

 Mexico. Few of the genera now usually adopted have many species ; quite often but 

 a single one. 



There has been much conflict of opinion concerning the food of these birds. From 

 their hovering so constantly about flowers, it was for a long time believed that they 

 were nourished solely upon the sweets extracted from the nectaries. Then insect? 

 were found in their stoujachs, and oiiinion veered to the opposite extreme. But doubt- 

 less both ^ i(!ws are correct; we know that the birds are extensively insect-eaters, and 

 the few that liave been preserved alive in confinement have been easily fed upon syrup 

 or sugar and water. Besides being the most active of birds, they are spirited, even 

 irascible, and at times extremely pugnacious; the males have fierce encounters in airy 

 tournament. They are not prox)erly gregarious, though so many often collect at 

 favorite feeding-grounds. They build exquisite nests, sometimes pensile, but ordi- 

 narily saddled upon a small bough or in a crotch, tastefully adorned outside, and at 

 the same time eliectively concealed, by being stuccoed over with bits of moss or lichen ; 

 within, they are warmly lined with the most delicate silky, cottony, or downy vege- 

 table substances. They never lay more than two eggs, which are white; and the 

 period of incubation is stated to bo twelve or fourteen days. 



Wilson knew but one North American Humming-bird, and Audubon only two or 



* It may not be generally known that under certain conditions the plumage of our 

 dullest birds will show rainbow-colors. A Sparrow's wing, for instance, held up to a 

 strong light, and half-spread, will give the spectrum, by decomposition of the solar ray 

 in passing through the fine barbules and barbicels, like that seen upon a soap-bubble. 



