THE CLASS BIBBS. 



313 



the condor (American vulture, Yulture of the Andes) and the 

 sea bird called frigate, are good examples of such powers of 

 flight. The dwelling of the condor is on the lofty peaks of 

 the Cordilleras, from whence he descends to the ocean at a 

 sweep, regardless of the effect of rapid changes in the tem- 

 perature and in the pressure of the atmosphere. They are 

 said to be strong enough to carry off in their talons sheep 

 and llamas, and when united in numbers, to attack and kill an 

 ox.* The birds called frigates have the wings proportionally 

 longer, and are met with in tropical seas at the distance of 

 four hundred leagues from land. 



Fig. 289. The Frigate Bird j Pelicanus Aquilus. 



To rise vertically, the wings of the bird must be carried 

 horizontally; but this is seldom the case, and from the 

 obliquity of their position they impress on the motions of 

 the bird an oblique ascensional movement : occasionally this 

 obliquity is so great that, in order to rise vertically through 

 the air the bird is obliged to fly against the wind. The 

 relative length of the remiges influences the facility with 

 which the bird rises in calm air. Birds which have the ante- 

 rior remiges the long-est and most resistant, have a more 



* The South African Vultures, which I have seen in vast numbers in 

 Southern Africa, have the same habits ; they are a cowardly bird, not- 

 withstanding their strength and size. R. K. 



