54 HABITS OF BIRDS. 



CHAPTER III. 



BIRDS, SOLITARY OR GREGARIOUS, ON ACCOUNT OF 

 SHELTER OR ASSISTANCE. 



UPON glancing back over the details which we have 

 already given of the solitary and social habits of 

 birds, it will be obvious, that their sociality produces 

 no apparent result, except it may be the appoint- 

 ment of a sentinel to give intimation of danger, if 

 such appointment (as may well be doubted) actually 

 takes place. Except in the instance of the sociable 

 grosbeak (Loxia soda) of Africa, we do not recollect 

 any authentic instance of birds uniting their efforts to 

 assist in performing a common work. Even in this 

 instance, the accurate observations of M. Vaillant 

 have proved, that so far from building streets, as 

 Paterson and others represent these birds to do, they 

 merely build their nests in actual contact*, as rooks 

 may sometimes be observed to do in this country. 

 The notion of their building streets is of the same cha- 

 racter with Pliny's account of the swallows in Egypt 

 raising an embankment to oppose the inundation of 

 the Nile, adopted by him from some hasty observer 

 who had seen the bank-swallows (Hirundo riparia), 

 not building (as he supposed), but mining into an 

 escarpment of the riverf. In the same way we find 

 it related by authors of celebrity, that when a pair of 

 sparrows take felonious possession of the nest of a 

 swallow, the swallow summons its companions to its 



* See Voyage, p. 3. 

 t See Architecture of Birds, p. 96. 



