340 



ZOOLOGY 



cessively to the place where they were produced, the young 

 building their nests in the vicinity of those of their parents. 

 Spallanzani removed a couple of swallows in a cage from the 

 nest where they were hatching from Pavia to Milan; on 

 being let loose they returned in thirteen minutes to their 



Fig. 332. The Parroquet (Ara). 



445. The instinct of sociability has also been alluded 

 to ( 329, 330, 339), an instinct, however, which prevails 

 mostly with insectivorous or granivorous birds. Birds of 

 prey are generally solitary, or live only in pairs. 



446. Birds differ also in the manner in which they pro- 

 cure their food : some search for it by day, others by night, 



