5o2 Allen, Evolution of Bird-song. [oct,. 



the form and character of the song; and sexual selection evolving, 

 through both structural and psychological changes, beauty of tone 

 and proficiency in execution. 



The letter of Mr. Saunders in the January 'Auk' has suggested 

 a further examination into the mode of development of the songs 

 of birds. Mr. Saunders raises an interesting question in regard to 

 the relation between the ordinary songs of certain species and the 

 ecstatic flight-songs. He makes a radical distinction between the 

 "ordinary song" and the " mating-song, " and states that "the 

 ordinary song is evidently not sung from sexual impulses, but is 

 simply an outburst of vocal sounds expressing great vigor and joy 

 of living," while " the mating-song, on the other hand, seems to be 

 caused directly by sexual impulses," and he goes on to say, "If we 

 would know the primary cause of bird-song in general, then the 

 question to be solved is which of these forms of song is the more 

 ancient." He decides this question in favor of the "mating-song," 

 and cites as his only evidence a certain flight-song of the Eastern 

 Meadowlark, which he says is almost identical with that of the 

 Western species, while the ordinary songs of the two species are 

 very different, indicating the ancestral character of this flight-song. 



He describes this song as "a* long-continued jumble of short, 

 quick notes," and says that it "quite closely resembles the flight- 

 song of the Bobolink (Dolichoiuj.v ori/zivorus)." This song is also 

 mentioned by Dr. Chapman in his " Handbook of Birds of Eastern 

 North America" (Revised Edition, p. 64). I have never been 

 fortunate enough to hear this song, which Dr. Chapman intimates 

 is not very frequently uttered by our Eastern bird, and which I 

 think, from my own experience and from inquiries I have made of 

 other ornithologists, must be very uncommon in Massachusetts, 

 where the "ordinary" song is certainly a mating-song, if not the 

 mating-song. I should like, however, to cite a few other examples 

 which seem to point to an opposite conclusion to that reached by 

 Mr. Saunders as to the priority of mating-songs in general. 



One of the most conspicuous examples of ecstatic flight-songs 

 among our Eastern birds is that of the Ovenbird (Seiurns aurocapil- 

 lus), and this song always (in my experience) contains a fragment of 

 the ordinary song of the species interpolated among its rich, melodi- 

 ous warbles. Does it not appear more likely that this flight- 



