14 BIRD FRIENDS 



birds, they become more wary and busy, so that 

 during June the volume of bird music gradually 

 becomes less as the birds drop out of the chorus one 

 by one. During July there is a still more marked 

 decrease, till by the end of the month nearly all the 

 birds have ceased singing, although a few continue 

 well through the summer, such as the house wren 

 and red-eyed vireo. When birds rear two broods, 

 this tends to prolong the song season. 



Time of day when birds sing. The bird chorus 

 begins in the early morning at earliest daybreak and 

 reaches its climax about sunrise and then declines 

 till it is nearly over by the middle of the forenoon, 

 although a few birds, like the wren, sing nearly all 

 day long. During the middle of the day most of 

 the birds are quiet. The chorus begins again late in 

 the afternoon and continues till some time after sun- 

 set. The evening chorus is not so vigorous and long- 

 continued as the morning chorus, although .some 

 species of birds sing rather more in the afternoon 

 than in the morning. 



The birds do not all begin and end their morning 

 song at the same time. Certain birds are usually 

 among the first to begin, an hour or more before 

 sunrise, such as the chipping sparrow, the robin, 

 and the song sparrow, and as the morning advances 

 other bu*ds join the chorus. This order in which the 

 different birds begin to sing is about the same from 

 morning to morning. 



