92 Habit and Instinct. 



and raucous; and a "tweet tweet" of pleasure, something 

 like the contented note of a canary bird. At the end of a 

 week there seemed to be five distinguishable notes or types 

 of note. First a harsh ** crek crek " when asking for food, 

 when excited in any way, or angry ; this was always 

 uttered in crouching attitude, with head thrown back and 

 the wings held out and forward, waving about in the 

 curious and exceedingly characteristic manner before 

 noted; secondly, a querulous call, expressive of discomfort; 

 thirdly, a sharper, quicker sound of pain, when, for 

 example, a moorhen's wing was seized by one of his 

 neighbours; fourthly, a gentle, persistent sound of con- 

 tentment; and, lastly, the canary-like "tweet tweet" of 

 perfect contentment. That, at any rate, the harsher note 

 is of suggestive value there seems no doubt ; for I have 

 again and again seen one thrown into the characteristic 

 attitude on hearing the "crek crek " of its companion. 



That suggestive warning notes are of great value to 

 birds in their free life can scarcely be doubted. Miss 

 Haywood says,* " I have frequently seen a bird that was 

 feeding quietly at the window unaware of my presence at 

 the other side, turn sharply round on hearing the warning 

 note of the robin, and look about it for danger." So, too, 

 it is a matter of familiar knowledge that, under natural 

 conditions, the various sounds made by the hen are of 

 suggestive value to her chicks; but how far the several 

 tones produce a congenitally definite response, or how far 

 the play of individual experiences reaches in this matter, 

 it is hard to say. Mr. Hudson, however, states, as the 

 result of personal observation, that a young bird hammer- 

 ing in the shell will cease in its efforts on hearing the 

 warning note of the parent bird. And he also states that 

 the warning cries of the foster-parent have no effect on 



* "Bird Notes," p. 39. 



