iSS.(.| BiCKNKI.I. oil llir Siiioinir III Hirds. 60 



In the p:iss;ii>-e of ccrtiiin species 011 their spiing migration, 

 there soinetinies appears to be a (hlVerence ol)ser\al)le lietween the 

 songs of the earher and hiter comers. As the first comers of 

 many birds nndonl)tedly represent the more northerly breeding 

 in(H\i(hials of their species, the fiict above cited may be of signifi- 

 cance in the c[uestion of geographical variation in song. 



Scasofial variation ifi so}ig\ — In several species there is a 

 difference, more or less decided, between the song of the breeding 

 season and that of the later scnig-period. How fir this mav 

 result from actual change of song with adults from spring to tall, 

 or how far from the etibrts of juvenile birds in the later season is 

 uncertain. Certuin it is, however, that the adults of some spe- 

 cies show a variation in song from one season to another. This 

 variation is not always that which would naturally result from a 

 reduced vocal impulse, which we might expect to follow the 

 breeding season, and to forerun decedent song. While in some 

 species variation in song from spring to fall is doubtless to be 

 attributed to this cause, with others the song of the later season 

 is of equal tone with that of the earlier, and may even be more 

 prolonged and much more varied, if not of greater power. These 

 facts will be illustrated bevond. 



Vocal variatio7i with age. — Of this class of variation I have 

 little to say, having never myself observed an unequivocal case of 

 the singing of a wild bird of the year. We find the young male 

 of the Orchard Oriole in full voice in its second year while yet 

 showing in its plumage plain evidence of its immaturitv. In seem- 

 ing contrast to this instance of the song of the adult being attained 

 before the adult plumage, I have found the male Purple Finch iir 

 the spring in tlie brown plumage of the female with a song decid- 

 edly inferior to and otherwise different from that of the mature 

 bird. As an instance of the singing of the young of one of our 

 native birds I may cite the fact of the young of the Mocking Bird 

 singing at the age of a few months while yet in the speckled 

 plumage. Mr. C. F. Holden assures me that this is the case, at 

 least when the species is kept in confinement. Mr. Holden also 

 tells me that the song of the young differs from that of the adult 

 much in the same manner that the voice of a child differs from 

 that of a grown person. In the summer the Redstart seems to 

 possess two types of song diftering in tone and accent, and obser- 

 vation goes to show that the more feeble performances are those 

 of immature birds. 



