150 Correspondence. [Jan. 



twitter of a winter flock of Tree Sparrows {Spizetta monticola). On the 

 other hand some true songs, according to the definition, are sadly unmusical 

 to human ears at least. The efforts of the male Yellow-headed Blackbird 

 (Xanthocephalus xanthocephalus) are a good example. 



One point about bird song which seems to have been more or less neg- 

 lected by most field observers, is that in many species the song differs from 

 the ordinary type during the short period of courtship. This difference 

 may be in the loudness or form of the song or in performances connected 

 with it. Thus the Song Sparrow (Melospiza melodia) and Yellowthroat 

 (Geothlypis trichas) rise in sudden ecstasy of flight song, and prolong the 

 vocal performance to several seconds longer than its ordinary duration. 

 The Meadowlark (Sturnella magna) also sings a flight song, but one abso- 

 lutely different from the ordinary song. It is a long-continued jumble 

 of short quick notes and quite closely resembles the flight-song of the 

 Bobolink (Dolichonyx oryzivorus). The Robin (Planestictus migratorius), 

 in the late days of April when mating is in progress, may be found singing 

 with its bill closed, the notes hardly audible for more than a himdred feet. 

 At such times its mate is nearly always to be found in the same tree, evi- 

 dently listening with pleasure to this whispered song, which is apparently 

 sung for its benefit only. This mating song of the Robin is a common 

 occurrence in the life of one of our most abundant birds. I have noted it 

 many times in many localities in the past fifteen years. It is common to 

 both eastern and western subspecies, yet most ornithologists seem to have 

 overlooked it entirely, for I have never seen mention of it in print, nor do 

 I know any ornithological friend who has observed it independently. 



This fact that many birds have two songs, an ordinary song and a 

 mating song, is significant in solving the problem of the origin of song. 

 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. Any 

 observer will note that this song is more commonly influenced by time of 

 day and weather conditions than by the presence of the bird's mate. But 

 the mating song, on the other hand, seems to be caused directly by sexual 

 impulses. 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. Did birds first begin to sing simply from joy of living, or were 

 the first songs induced by the period of courtship, and the ordinary song 

 evolved later? 



One observation which seems to give some evidence pointing to the 

 greater antiquity of the mating song is furnished by the Meadowlarks 

 (Sturnella magna and S. neglecta). Both the Eastern and Western 

 Meadowlarks have ordinary and mating songs, the former short and most 

 commonly rendered from a perch, the latter long-continued and always 

 sung on the wing, frequently in pursuit of the mate. The great dif- 

 ferences in the ordinary songs of these two species is too well known to 

 need comment, but the similarity of their mating songs is less well known. 

 In fact I have never seen these flight songs mentioned in print by any 



