_>2 THE AMERICAN .MIDI. AM) NATURALIST 



day, he must feel certain that the warbler is in a state of exuberant 

 joyousness. 



But why is there such a variety of notes in the many common 

 birds of our woods and fields? Bach species has voice qualities 

 that are distinct from any oilier, and even individuals of the same 

 species often manifest great powers of variation in their singing. 

 Speaking generally, I think a bird's song is an inherited gift in 

 this sense, that the elementary powers of utterance are possessed 

 by the bird but depend for development on association with the 

 parent birds. 



This development of song power may be noticed in young 

 birds during the period that follows the nesting season, when fami- 

 lies of birds wander about for food. Better still in our groves, 

 during July and August, such species as the Bluebird and Balti- 

 more Oriole are common, and here their notes may be heard, 

 especially early in the morning or in the evening. Hearing these 

 notes so frequently, an ear accustomed to distinguish the utterance^ 

 of birds will readily recognize that efforts of the young birds are 

 characterized by a lack of both sustained execution and of fullness 

 of voice expression. 



In some species the most prominent feature of the song is the 

 qualitv of the notes, which may have but little variety and yet 

 be very pleasing. Such a species is the Bluebird. In others the 

 notes may be clear, but unless the performance is notably fine, 

 the total effect of the song is disappointing. This fact may be 

 easily observed in the Song Sparrow. In judging of a bird's powers 

 of song the quality of the notes seems to weigh most in the mind of 

 the observer. Very often a note will have scarcely any variation, 

 and yet be indescribably sweet or plaintive. 



Two species that are notable for great variety in their singing 

 are the Brown Thrasher and the Catbird. There is also considerable 

 similarity in their songs, the Thrasher's performance, however, 

 being easily distinguished by its greater strength and more marked 

 pauses. In some respects the Catbird's song is the more pleas ng, 

 for what it lacks in force of expression it makes up in the sweetness 

 of its strain. 



The Catbird suggests a faculty that is most remarkable in 

 this species — the power of imitation. Probably this is not an 

 uncommon endowment in many species, and may account 

 for peculiarities of individuals that are noticed in their manner 



