i64 GENERAL ORNITHOLOGY tart ii 



general, the axillars, or axillary feathers (Lat. axilla, the armpit). 

 These are the innermost feathers lining the wings, lying close to the 

 body ; almost always longer, stifFer, narrower, or otherwise pecu- 

 liarly modified. In ducks, for example, and many of the waders, as 

 snipe and plover, they are remarkably well developed. The colour 

 of the axillaries is the principal distinction between some species of 

 plovers. The 



Remiges, or Flight-Feathers (Fig. 30, h, s, and t), give the Aving 

 its general character, mainly determining both its size and its shape ; 

 they represent most of its surface and of its inner and outer borders, 

 and all of its posterior outline, forming a great expansion, of which the 

 bony and fleshy framework is insignificant in comparison. The 

 shape of the wing is indeed primarily affected by the relative 

 lengths of its bony segments, the upper arm being, in a humming- 

 bird, for example, very short in comparison with the terminal 

 portion of the limb, and in an albatross again, both upper and fore- 

 arm being greatly lengthened ; still in any case it is the flight- 

 feathers that mainly determine the contour of the wing, by their 

 absolute degree of development, their lengths proportionately to 

 one another, and their individual shapes. They collectively form a 

 thin, elastic, flattened siirface for striking the air, quite firm along 

 the front border where the bone and muscle lie, thence growing 

 more mobile and resilient toward the posterior border and along 

 the outer edge. Such surface may be quite flat, as in such birds as 

 cut the air with long, pointed wings, like oar-blades ; but it is 

 generally a little concave underneath, and correspondingly convex 

 above ; such arching or vaulting of the wing-surface being usually 

 associated with a short, broad, rounded wing, as in the gallinaceous 

 tribe, and being least in birds which have the thinnest and sharpest 

 Avings. Corresponding differences in the mode of flight result. 

 The short, rounded wing confers a powerful though laboured flight 

 for short distances, usually accompanied by a whirring noise result- 

 ing from the rapidity of the Aving-beats ; birds that fly thus are 

 almost always thickset and heav3^ The long, pointed wing gives a 

 noiseless, airy, skimming flight, indefinitely prolonged, and accom- 

 plished with more deliberate wing-beats ; birds of this style of 

 wing are generally trim and elegant. These, of course, are merely 

 generalisations of the extremes of modes of flight, mixed and 

 gradated in every degree in actual bird-life. Thus the humming- 

 bird, which has sharp, thin wings, whirs them fastest of all birds,^ — 

 so rapidly that the eye cannot follow the strokes, merely perceiving 

 a haze about the bird while the ear hears the buzzing. The com- 

 bination of acuteness and concavo-convexity is a remarkably strong 

 one, conferring a rapid, vigorous, whistling flight, as that of a duck 

 or pigeon, or the splendid hurtling of a falcon. An ample wing, as 



