









"language." In part, this language is expressed vocally; a duck is aware of 

 its companions through auditory as well as visual perception. The peeping 

 of ducklings holds the brood together in dense vegetation, and their voicings 

 identify their position to their mother. In turn, the ducklings follow the low 

 voice of the parent when she moves ahead of them in dense growth. When 

 Mallards and Pintails fly northward on April evenings, I hear their soft 

 chuckles, which undoubtedly are a factor in holding bands together when 

 overtaken by darkness. On evenings when Coots move in spring passage I 

 can mark the pattern of their unseen numbers by voices drifting down. 

 April nights are alive with the cheeps of migrant songbirds. Such simple 

 notes are termed "contact-calls." The contact-call has no seasonal perio- 

 dicity. Often it is as clear a mark of identification as the feathers themselves. 

 It identifies the individual of the species and its position. Such notes are 

 generally short, simple, and, for many species, easily imitated by man. While 

 I was writing this page, a Black-crowned Night Heron passed over the 

 marsh close by, and from my door I uttered a loud "quock." The bird turned 

 immediately to bend its flight my way. Contact-calls function to hold a 

 group of birds together, and probably tell very little of what the individual 

 is doing. 



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