108 A CATAIOGUE OF THE BIKDS 



or shakings," so ''as to represent the shivering motion of the 

 wings during flight." Such movements of the arm are undoubt- 

 edly necessary to the production of the tremulous or vibratory 

 character of the sound, by making the breaks in it that give the 

 neighing or bleating effect. But, granting that the " shakings" 

 of the arm represent ever so truly the " shiverings of the wings," 

 what can this have to do with the noise that is supposed to be 

 made by the tail-feathers during the bird's descent through the 

 air? The bird descends because the flight movements of the 

 wings have ceased; the peculiar curve and inclination of the 

 descent are regulated by the out-spread tail ; the sweep itself is 

 perfectly steady and uninfluenced by a tremulous, vibratory or 

 " shivering" motion of the wings. There can be no doubt, that 

 while rushing through the air in rapid descent, with firm set 

 tremulous wings and the tail rigidly spread, the trunk of the bird 

 is in extreme tension, and is as steady in its flight as an arrow. 



These experiments, upon which much stress is laid, appear to 

 have little real value. And in the characters of the so-called son- 

 orous feathers themselves there is just as little, in my opinion, to 

 justify the theory. It is said that the form of these feathers is 

 peculiar, and that the inner web is wide, with the rays very long 

 and strongly adherent to each other ; and that the shaft is very 

 strong and sabre-shaped. Such are undoubtedly the characters 

 of the two outer tail-feathers of the Common Snipe; but in 

 some of the other species there is scarcely any web at all. The 

 feathers vary much in the different species ; the shaft is, how- 

 ever, in all more or less sabre-shaped, and strong. But such is 

 also the case in a great number of the waders, which certainly 

 do not produce the peculiar sound made by the Snipe. In all 

 these birds most of the tail-feathers partake of the above charac- 

 ters, and become more and more bent as they approach the sides. 

 The width and firmness of the web vary much. In the Wood- 

 cock, as in the Snipe, it is wide, but not by any means so firm 

 in the former as in the latter ; the Great Snipe is stated to have 

 four of those so-called sonorous feathers on each side ; they are 

 considcral)ly narrower and softer than those of the Common 

 Snipe. In the Jack Snipe the sabre form is slight and the web 



