SOLITARY AND GREGARIOUS. 29 



the raven was answered by the alarm-call of the 

 leader of a small flock of sheep who were feeding 

 on the scanty herbage of this lofty region ; and, at 

 the signal, they quickly drew closer together, and, 

 forming a " serried phalanx," eyed their enemy 

 with a bolder bearing than we could have deemed 

 possible in animals proverbial for timidity. The 

 raven was not long in discovering that he had 

 little chance of singling a victim from so watchful and 

 wary a band, and flew off towards the neighbouring 

 cliffs, where he might chance to light upon the 

 carcass of one left undevoured by some fox scared 

 from his prey, or accidentally precipitated, as we 

 have seen happen, from the rocks above. On the 

 departure of their enemy, the sheep began to feed 

 again, but warily at first, raising their heads at in- 

 tervals to assure themselves that he was really gone ; 

 while, to render assurance doubly sure, their leader 

 again took his station as sentinel for the common 

 weal *. 



Now we are disposed to conclude, that these two 

 cases of the sheep and the raven may, so far as food 

 is concerned, be taken as the general conditions of 

 the solitary and gregarious habits of birds. One 

 whose food is confined to living prey will prowl alone, 

 because along with associates he might fare scantily ; 

 while those who feed on seeds and other vegetable 

 substances, easily obtained in abundance, congregate 

 that they may feed more safely, by appointing, as the 

 mountain sheep do, a sentinel to warn them of dan- 

 ger. The raven, indeed, can hardly be looked upon 

 as subsisting wholly on living prey. It is not 

 furnished by nature with sufficiently formidable wea- 

 pons for this purpose ; and almost uniformly when 

 carrion cannot be obtained, it attacks lambs, sickly 

 sheep, or such as have fallen into a ditch or bog, 

 * J. R. 



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