1SS4.I BlCKNKI.L OJI till' Si//irilin- 0/ Hilih. 67 



its gambols in the May meadows; or the Orchard Oriole, which 

 passes witii iiniiiterriipted song from tree to tree. With others 

 the indulgence of the habit is less matter-of-fact, and singing on 

 the wing is the accompaniment only of special fligiits. But the 

 habit reaches a still greater specialization. Among those species 

 with which it is conHned to the season of courtship it is 

 variously exhibited as a general habit, as a special habit, and 

 again as a reserve habit apparently set apart for particular and in- 

 frequent indulgence. As an instance of a species witli which the 

 habit is a general one, the Yellow-breasted Chat may be cited. 

 Where these birds abound their ridiculous acrobatic song-flights 

 may be daily witnessed. With the Purple Finch, though the 

 habit may also be regarded as a general one, it is much less fre- 

 quent. In the Golden-crowned Thrush we discover a great 

 specialization of the song-flight, the vocalization accompanying 

 the flight being of a high order and utterly different from the ordi- 

 narv song of the species. Nor it is commonly to be heard, for 

 either the ability to produce it is confined to favored individuals, or 

 it is only indulged on special occasions, or under an extreme 

 degree of mental excitement. The cause of these song-flights. 

 and of the extravagant demeanor with which they ai'e conducted 

 by some species, can be attributed only to some unusual state of 

 mental excitement, which wields an irresistible power over its 

 subject. 



Compared with ordinary vocalization, singing under these cir- 

 cumstances seems to represent a higher vocal effort, as it certain- 

 ly does a higher vocal accomplishment. Hence it is not suprising 

 that these unusual demonstrations should occur under the intense 

 sexual excitement of the breeding season, but why with some spe- 

 cies they should be continued into the autumn, or even be de- 

 ferred until the breeding season is passed, seems inexplicable. Yet 

 with a number of our birds this is the case. So far as my own 

 observation has extended, it is true of all those species with which 

 aerial song-flight appears to be only occasional or exceptional. 

 And thus in several cases where I have obsened but a single 

 instance of song-flight in a species, my record of the performance 

 dates in the fall. The Indigo Bird and the Swamp Sparrow mav 

 be cited as examples. The Maryland Yellow-throat is a species 

 with which aerial song-flight is not an uncommon habit, but 

 appears never to belong to the early spring. Not until the summer. 



