Genus Falco, 183 



all the species of true falcons is still further illustrated by the 

 form and substance of the os furcatorlus, which is circular, broad, 

 and strong, affording a permanent support to the shoulders. That 

 the long and acuminated form of the wing in the true falcons, 

 with each feather narrow, firm in consistence, the second the longest, 

 and all gradually tapering to a point, is also best adapted for 

 rapidity of motion, may be inferred from the examples in the 

 various species of the genera Hirundo^ Scolopaxy Tringa^ Chara- 

 drius, Procellaria, Sterna^ Sfc. ; but that extent of surface, and 

 this peculiarity of form in the wing, are not in themselves suffi- 

 cient alone to afford rapid flight, is proved in the genus Larus^ the 

 species of which, though capable of exercising their immense pin- 

 ions with graceful ease for hours in succession, without any apparent 

 lassitude, are still incapable of rapid flight, for want of strong 

 pectoral muscles, and their consequent specific gravity. The nu- 

 merous examples also furnished by the Gallinaceous tribe suffici- 

 ently evince, that immense pectoral muscles are insufficient 

 when coupled with a small round wing, and afford but a short 

 flight, sustained with great labour, rapid in a small proportion 

 only to the strength and repetition of the impulse, and accom- 

 panied by a vibration too well known to need further remark. So 

 material also is the perfection of the feather in the genus Falco, 

 that when any of those of the wing or tail are broken, the flight 

 of the bird is so injured that falconers find it necessary to repair 

 them. For this purpose they are always provided with both 

 pinion and tail feathers accurately numbered, and the mode of 

 uniting the more perfect feather to the injured stump is described 

 in Sir John Sebright's excellent observations on hawking. 



It is difficult to estimate the comparative rapidity of flight in 

 different birds, and our pigeons may appear to possess this advan- 

 tage in a degree little inferior to the true Falcons, but these 

 birds are deficient in natural courage, and are unable under cer- 

 tain circumstances^ to avail themselves of those powers with 

 which they are gifted : to these examples others might be added, 

 and the impression produced by the threatened attack of a power- 

 ful enemy is not confined to birds. 



The bodies of all the species of true Falcons, when denuded of 



