52 yournal of Comparative Neurology ami Psychology. 



low that the eye gazes at one from under the perch ; if in the nest, 

 the position usually is less perpendicular, the tendency being to sink 

 not only the head but the whole body into the nest. When the nest- 

 call is given in a corner, the bird's face is turned towards the wall. 

 The eye is partly closed, and may be entirely closed in moments of 

 ecstasy. The feathers of the whole body are comfortably appressed. 

 During the time this attitude is held, there is always a gentle flipping 

 of .the wings. This gentle wing-flip, considered merely as a move- 

 ment, is usually quite different from the wing flutter of the young 

 bird begging for food ; for the strokes of the wings are made singly, 

 at as slow a rate sometimes as two per second, and the movement is 

 chiefly confined to the ti]) of the wing. But, considered psychologic- 

 ally, the nest-calling wing-flip bears an unmistakable resemblance 

 to the begging expression, for it is given wath reference to another 

 bird, with a supplicatory significance ; this is ' more evident in the 

 female than in the male, and is seen especially when she is anxious 

 for sexual union ; in such case her wing movement may become a 

 true flutter, and she may flutter separately that wing which is next 

 to her mate, thus exhibiting clearly the similarity between her wung- 

 flip and that of the begging young. But, whereas the fluttering -of 

 the hungry youngster is notable for its violence, the wing flutter of 

 the amorous adult is notable always for its gentleness. 



The nest-call is always given singly. Though the bird may con- 

 tinue nest-calling for many minutes together, there is invariably 

 a considerable interval between each call and the next. These inter- 

 vals of silence give opportunity for the vocalist to look about and 

 watch the bird to which it is calling, and also to express its feelings 

 by the wing-flip just described; for, during the effort of uttering the 

 coo, the dove must hold its body rigid, the head square to the front, 

 and the wings tight against the sides ; only in the intervals between 

 coos can it give the delicate flipping movement of the wings. 



The sound of the nest-call differs in several respects from that of 

 the other coos. The nest call is less loud than the others; the 

 guttural at the close is usuall}' omitted altogether. But this is the 

 most protracted of all the coos, its individual notes, especially the 

 last two out of the three, being of long duration ; this protraction 



