62 SONG 



Each species will offer its own problem, but in every instance the 

 greatest interest will center about the life of the nest, where the com- 

 plex relations of parent with parent and of both with offspring, supply 

 occasions for the utterance of notes heard under no other conditions. 

 Not the least interesting of these will be the warning calls by which the 

 adult conveys to her inexperienced, or even blind, young, knowledge of 

 a threatening danger, in the presence of which they must betray no 

 sign of life. Perhaps no one case more strongly illustrates the impor- 

 tance of a means of exact communication among birds, for failure to 

 understand and obey may here be followed by death. 



Song. As a rule, the songs of birds are uttered by the male alone 

 and mainly or only during the nesting season. It is true that in rare 

 cases the female sings; the female Cardinal and Rose-breasted Gros- 

 beak, for example, sometimes sing to a limited extent, and the female 

 of a certain tropical American Wren (Pheugopedius rutilus) sings a 

 delightful duet with her mate. It is also true that some birds sing more 

 or less throughout the year, while many have a short, second song- 

 season after the postnuptial molt. But song in its full development, and 

 with its real significance, is restricted to the nesting-season. It is, 

 therefore, a secondary sexual character, an irrepressible manifesta- 

 tion of the greatly increased vitality of the bird during the period of 

 reproduction. 



The systematist classifies as Oscines, or true singing birds, those 

 species which have the "syrinx with four or five distinct pairs of intrinsic 

 muscles, inserted at ends of three upper bronchial half-rings and thus 

 constituting a highly complex and effective musical apparatus" (Coues) ; 

 but while this group contains the most gifted singers, it does not by any 

 means contain all our song birds, many species having a less highly 

 developed syrinx with fewer muscles, which are inserted into the middle, 

 not the ends, of the bronchial half-rings, still being able to produce both 

 pleasing and complex vocal sounds. Note, for example, the songs of 

 certain Snipe and Plover or of Goatsuckers. On the other hand, some 

 true Oscines, like Crows, Magpies, and Jays, with a highly developed 

 vocal apparatus, are practically songless, while the Cactus Wren, a 

 member of a family of noted songsters utters only harsh squawks. 



Song, therefore, is not restricted solely to the Oscines, but in a 

 broad sense is the attribute of every species of birds which gives expres- 

 sion to the emotions inspired by the nesting-period. The whistling of 

 Grebes, the 'bleating' of Snipe, the 'booming' of Bitterns, the 'trumpet- 

 ing' of Cranes, the 'whinny' of Soras or 'cooing' of Doves, the hooting 

 of the Owls, are, therefore, types of songs, and we may even include 

 here such mechanical forms of bird music as the 'drumming' of Grouse, 

 tapping of Woodpeckers or 'booming' of Nighthawks. 



Through the exercise of these vocal and instrumental gifts, which so 

 delightfully voice the joys and hopes of spring, the male bird replies to 

 the challenge in kind of a rival, and what is of far more importance, 

 informs the female of his presence. 



