Craig, Expressions of Emotion in Pigeons. 47 



Yet the sounds themselves are sufficiently different for a person 

 familiar with the birds to tell, usually, by the ear alone, which of the 

 three coos is being given. Professor Whitman has named the three 

 types respectively, the perch-coo (or song), the bowing-coo, and the 

 nest-calL 



(I) TJie perch-cvo, or song. The perch-coo of the ring-dove is its 

 song, properly so-called. While singing, in almost every instance, 

 the bird sits on the perch, hence the name perch-coo. Less commonly 

 the bird sings on the ground, and rarely in the nest. 'No special 

 concurrence of outward circumstances is needed to move the bird to 

 sing, for the perch-coo seems to express, in many cases, simply a 

 feeling of good spirits ; in this, the song differs somewhat from the 

 other two forms of coo, which are usually reserved for special occa- 

 sions or particular situations. The perch-coo is the only utterance 

 of the adult ring-dove that ever appears to be given and enjoyed 

 purely for its own sake (cf. p. 33) ; in this sense it may properly be 

 regarded as "play." Of course the feeling of good spirits which is 

 expressed in this coo is favored by outward circumstances which are 

 comfortable or stimulating. Singing is most frequent in spring time, 

 when the birds are in the fullest vigor and vitality; it diminishes 

 during the summer as vitality is lowered by the exhausting labors 

 of the breeding-season ; it is least indulged in during the autumn, at 

 which time the molt renders the bird somewhat unwell. But in the 

 spring time, the season of lusty singing, the perch-coo may be repeated 

 at intervals from dawn till sunset, irrespective of what passes during 

 the day. The only circumstance which, to my knowledge, acts as 

 an immediate excitant of the perch-coo, is the sound of another bird 

 singing in the distance. There are occasions when the birds answer 

 and re-answer one another for considerable periods, and the perch- 

 coo is invariably used in such cases of simply calling-and-answering. 

 It is thus seen that even this case, the only case in which the perch- 

 coo is directly related to the environment, partakes of the nature of 

 play. 



No highly specialized attitude or movement accompanies the utter- 

 ance of the perch-coo, no movement save what facilitates vocalization. 

 The bird simply stands in the normal perching position (Plate I, 



