70 THE ARCHITECTURE OF BIRDS. 
performs the office of incubation; another, consist- 
ing of a little thatched roof and covering a perch, 
without a bottom, is occupied by the male, whoywith 
his chirping note, cheers the female during her ma- 
ternal duties.” 

Nest of the Baya. 
The sociable grosbeak (Lovia socia) seems to ex- 
cel both the preceding species in the extent, if not 
in the skill, of its workmanship. ‘I observed,” says 
Vaillant, ‘‘on the way a tree with an enormous nest 
of those birds to which I have given the appellation 
