STRUCTURE OF BIRDS 



These feathers (the primaries) vary greatly in 

 different species. By their length, rigidity, and 

 flexibility, and their shape, they decide the speed 

 and characteristics of the bird's flight. They 

 are long and pointed in birds of the hawk type ; 

 shorter and rounded in species like the partridge. 

 The feathers growing from the fore-arm are termed 

 secondaries, while from the base of the hand 

 springs the winglet or bastard wing, as it is often 

 called. The study of the conformation of wings 

 is most interesting. Birds of no two species, or, 

 at any rate, of no two genera, fly exactly alike, 

 and the wing formation in each case differs in 

 order to meet the different requirements. 



The flight of the night-feeding birds is perhaps 

 the most remarkable of any. How is the airy 

 buoyancy attained which enables them, the owls 

 especially, to waft themselves, soundless as 

 shadows, along the dark hedge-rows and across 

 the gloom-hidden fields ? In the owls the number 

 of quill feathers is equal to that of birds of the 

 most powerful wing, giving them the greatest 

 facilities for sustained and rapid flight. Their 

 noiseless movements are not attained by any 

 diminution of force. But the texture of the 

 feathers differs essentially from that of the falcon 

 and of most other birds. It is of the downiest 

 softness, and the fibres of the wing- webs, being of 

 unequal length, allow a free passage to the air, 

 and are so pliable that they yield to the hghtest 

 pressure. This is the secret of the night-bird's 

 flight. ' ' The way of the bird in the air " is one 

 of those marvels that have puzzled many thinkers 

 besides Solomon. The same wondering train of 

 thought that arose in the mind of the upv^^ard 

 gazing patriarch in the far-off past, springs up in 

 the mind of the naturaHst to-day, as his eye 



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