expressive notes ; they hoot in a fine vocal sound, 

 much resembling the vox humana, and reducible by 

 a pitch-pipe to a musical key. This note seems to 

 express complacency and rivalry among the males : 

 they use also a quick call and a horrible scream ; 

 and can snore and hiss when they mean to menace. 

 Ravens, besides their loud croak, can exert a deep 

 and solemn note that makes the woods echo ; the 

 amorous sound of a crow is strange and ridiculous ; 

 rooks, in the breeding season, attempt sometimes in 

 the gaiety of their hearts to sing, but with no great 

 success ; the parrot-kind may have many modula- 

 tions of voice, as appears by their aptitude to learn 

 human sounds ; doves coo in an amorous and mourn- 

 ful manner, and are emblems of despairing lovers ; 

 the woodpecker sets up a sort of loud and hearty 

 laugh ; the fern-owl, or goat-sucker, from the dusk 

 till daybreak, serenades his mate with the clattering 

 of castanets. All the tuneful passeres express their 

 complacency by sweet modulations, and a variety of 

 melody. The swallow, as has been observed in a 

 former letter, by a shrill alarm bespeaks the atten- 

 tion of the other hiruiidines, and bids them be aware 

 that the hawk is at hand. Aquatic and gregarious 

 birds, especially the nocturnal, that shift their quar- 

 ters in the dark, are very noisy and loquacious ; as 

 cranes, wild-geese, wild-ducks, and the like : their 

 perpetual clamour prevents them from dispersing 

 and losing their companions. 



Ill 



