•8S4.] BiCKNKLL on the Singing of Birds. 211 



June. Absence about this time in several recent years has inter- 

 fered with my observations, but attentive visits to favorite haunts 

 of the species in the hist week of several Junes failed to show that 

 it had not then become silent. Sometimes, indeed, it appears to 

 cease singing soon after the end of May ; again it may continue 

 intermittently nearly to the end of June, and I have recorded a 

 few isolated dates of song- in earl}' July. 



A supplementary song-period occurs in August, usually about 

 the middle of the month ; beginning, according to my records, 

 August 5 to 15, and ending August 18 to 24. Though the true 

 spring song is then recovered, it is largely superseded by a 

 markedly different song, which seems to be especiall}- charac- 

 teristic of the later season. 



I have heard both songs succeed one another from the same 

 bird. Representing the spring-song as Ce-e-e-e — ker-r-r-r-r., 

 the later song would compare somewhat as follows : Ker-r-r-r — 

 kik-kik-kik-kik. An approach to this song is sometimes notice- 

 able tov\^ards the end of June ; and the only songs of the species 

 that 1 ever heard in July were much like it. In one season its 

 song was not infrequent during the spring. 



At the time of the resumption of singing in mid-August, before 

 the species has come into possession of its full powers, I have 

 sometimes heard some singular vocalization from it — a series 

 of low, disconnected notes, um-ecognizable as being from this 

 species, sometimes, however, ending with the sharp K'ik^ kik^ 

 kik^ kik^ of the later song. This song sometimes strikingly 

 suggests that of the Nashville Warbler. 



At the time of this strange vocalism I have found the species 

 completing a renewal of plumage, but with many feathers still in 

 active growth. A little later, when singing is regularly resumed, 

 the bird appears in its new attire, which is of a silken beauty, 

 with even fresher and brighter colors than in the spring. 



In view of the fact that hybridization seems to be established 

 among certain species of the group to which this Warbler 

 belongs, the above noted variations in song and time of singing 

 may be due to other than merelv individual and seasonal causes. 



Helminthophila ruficapilla ( JV/Zs.) Ridgzv. Nashville 



Warbler. 



Sings regularly on its spring migration, but I have never heard 

 it in the fall. 



