182 EVOLUTION OF BIRD-SONG 



startled from its perch, utters a loud, harsh, and 

 grating cry, similar to the interrupted creakings of a 

 watchman's rattle, and almost, as it were, the vocal 

 counterpart to the watery tumult amidst which it 

 usually resides (Nuttall's Manual, ed. Chamberlain, 

 vol. i. p. 462, per Mr. A. H. Macpherson). 



Several birds of the duck family have whistling 

 cries. The shelduck whistles, as I have observed. So 

 does the wigeon. The summer duck cries peet peet 

 (Wilson, op. cit. p. 322). The velvet scoter has short 

 squeaking notes (ibid. p. 218). The whooper has a 

 whistling cry (Yarrell), and, like the mute swan and 

 the mallard, the sound of its wings in flight can be 

 heard at some distance. Birds accustomed to long 

 flights, and to a life in lonely places, would observe 

 sounds caused by flight, especially at the times of 

 migration. 



The voices of mallards, pelicans, flamingoes, and 

 herons resemble the croaking of frogs and toads. 



The cry of our common swift has been well 

 suggested in the words swee ree (Harting, Birds of 

 Middlesex, p. 128); and this, although used by the 

 young in the nest and when chasing their parents 

 for food, is most noticeably employed by the adults 

 on a particular occasion when they are pursuing 

 each other, or are flying at a great pace together, 



