VOICE OF BIRDS. 63 



is a most welcome promise of spring. Then follow the 

 Robins, Blackbirds, and other migrants, until, late in 

 May, the great springtime chorus is at its height. 



The Bobolink is the first bird to desert the choir. 

 We do not often hear him after July 5. Soon he is fol- 

 lowed by the Yeery, and each day now shows some fresh 

 vacancy in the ranks of the feathered singers, until by 

 August 5 we have left only the Wood Pewee, Indigo 

 Bunting, and Red-eyed Vireo — tireless songsters who 

 fear neither midsummer nor midday heat. 



Call-Notes. — The call-notes of birds are even more 

 worthy of our attention than are their songs. Song is 

 the outburst of a special emotion ; call-notes form the 

 language of every day. Many of us are familiar with 

 birds' songs, but who knows their every call-note and 

 who can tell us what each call means ? For they have a 

 meaning that close observation often makes intelligible. 



Listen to the calls of the Robin and learn how unmis- 

 takably he expresses suspicion, alarm, or extreme fear ; 

 how he signals cheerfully to his companions or gives the 

 word to take wing. Study the calls of the Crow or Blue 

 Jay, and you will find that they have an apparently ex- 

 haustless vocabulary. 



It is supposed that birds, like men, do not mherit 

 their language, but acquire it. Thus there are recorded 

 instances of young birds who had been isolated from 

 others of their kind, learning to sing whatever song they 

 heard. On the other hand, it is said that a bird inherits 

 its own notes, at least to some extent, and, while it may 

 not sing the song of its species perfectly, its song will 

 still be sufficiently characteristic to be recognizable. 

 There are, however, very few satisfactory observations 

 on this subject, and keepers of cage-birds have here an 

 excellent opportunity for original investigation. 



