U WARHI.IvR SONGvS. 



song period sing- then, but that a few do. Man>- are too fat 

 to sing, and no doubt many do not sufficiently reco^'er from 

 the debihtating effects of the molt to sing. 



It is not unusual to hear feeble attempts at .song early in 

 the autvmm from not fully fledged birds, sounding like a 

 bird whose vocal chords were unable yet to respond to the 

 will. Gradvially the .song becomes more and more perfect as 

 the days pass until it again becomes normal. Many times 

 these are not young birds, but old ones just completing the 

 molt. Disuse of the' vocal muscles, or change due to the molt 

 may account for these first unsuccessful attempts at song re- 

 newal. 



TWO KINDS OF SONG. 



We .shall not proceed far in our study of Warbler songs 

 before we are greeted with surprises. We shall find that all 

 of the individuals of a species do not sing alike, and that the 

 same individual is not always confined to one style of song. 

 Sometimes the variations may be considerable, sometimes 

 scarcely worth noting. We shall not proceed far in our study 

 of these variations before we maj^ be greeted to a fresh sur- 

 prise in the form of a song wholly different from anything be- 

 fore heard from the bird, which cannot be forced under the 

 designation 'variation.' It is something apart from the ordi- 

 nary utterance, both in quality and quantity. The manner of 

 utterance strongly suggests that this is a passion song. We 

 are now forced to distinguish between what we have before 

 considered the song of the species and this newly discovered 

 song. For convenience the first one may be designated the 



CALL SONG. 



What do we mean b>- Call Song ? It is the song which 

 we hear commonly: the .song of every day, uttered under no 

 special .stress of circumstances, as a sort of accompaniment to 

 the usual activities. It is an announcement to all other birds 

 within hearing, of the singer's whereabouts. It becomes a 

 di.stinct mate call when the breeding grounds have been 

 reached, if it could not be .so considered before. After mat- 

 ing and the selection of the nest .site it becomes an announce- 

 ment of ownership and a warning to all trespas.sers. During 



