60 THE VOICE OF BIRDS 



118. 1909. WATSON, J. B., Some Experiments on Distant Orientation. 

 Papers from the Tortugas Lab. of the Carnegie Inst., II, pp. 227-230. 

 1909. WEIGHT, H. W., Birds of the Boston Public Garden. A Study in 

 Migration, 229 pp. (Houghton, Mifflin & Co.). 1910, HENSHAW, H. W., 

 Migration of the Pacific Plover to and from the Hawaiian Islands, Auk, 

 XXVII, pp. 246-262. 1911. COOKE, W. W., Our Greatest Travelers, Natl. 

 Geog. Mag., XXII, pp. 346-365, 12 maps. 



THE VOICE OF BIRDS 



Call-Notes 

 Song 



The gift of song is the bird's most appealing and '^harming attribute; 

 but, wholly aside from their esthetic importance, the notes of birds have 

 an especial interest for every one who would attempt to interpret and 

 ascertain their significance. The weird cries and enraptured warbles 

 which are often so strangely expressive of nature itself and which so 

 strongly appeal to the wild and primitive within us constitute, in truth, 

 the language of birds, to understand which is to bring one to a new and 

 intimate knowledge of bird-life. It is out of the question to present 

 here anything like an adequate essay on the calls and songs of birds, 

 but the subject is so attractive, and its investigation is so well within 

 reach of the local or isolated student, that it must at least be treated 

 in sufficient detail to suggest lines of study. 



Call-Notes. The term call-notes is somewhat loosely applied to a 

 great variety of bird utterances, including true call notes as well as 

 notes or 'calls' of alarm, anger, etc. 



The student may first consider the origin of voice in birds, begin- 

 ning with silent species, like the Man-o'-war-bird and Brown Pelican 

 (though the young of both are noisy enough), through others, like the 

 Cormorant, Water-Turkey, or Black Vulture, which utter only the 

 most rudimentary sounds, to those which have acquired an extended 

 vocabulary, like the Crow or Jay. Then may follow a study of the calls 

 of young birds. With altricial birds, which are reared in the nest, the 

 hunger or food-call with which the returning parent is greeted is the 

 most characteristic, and is common to such unlike birds as Thrushes 

 and other Oscines, Swifts, Pelicans and Herons, in fact, doubtless, to 

 all birds which are fed in the-nest. 



On the other hand, with prsecocial birds which follow the parent 

 shortly after birth, what may be termed the 'lost' or 'location' call is 

 the most important. Here the chick is quickly taught to feed itself, 

 and its life depends chiefly on its ability to keep up with the flock and 

 receive parental care and guidance. The peep of a chick or duckling 

 will be readily recalled as a note of this kind. 



When threatened by danger, both altricial and prsecocial young, as 

 a rule, try to avoid observation by squatting a,nd remaining motionless, 

 but young Vultures hiss in the most curious manner; young Pelicans 



