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. Wricut, H. W., Birds of the Boston Public Garden. A Study in 
Migration, 229 pp. (Houghton, Mifflin & Co.).—1910, Hzensuaw, H. W., 
Migration’ of the Pacific Plover to and from the Hawaiian Islands, ‘Auk, 
XXVII, pp. 246-262.—1911. Cooxs, W. W., Our Greatest Travelers, Natl. 
Geog. Mag., XXII, pp. 346-365, 12 maps. 
Tue Voice oF BirDs 
Call-Notes 
Song 
The gift of song is the bird’s most appealing and charming 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 precocial birds sihioh 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 precocial young, as 
a rule, try to avoid observation by squatting and remaining motionless, 
but young Vultures hiss in the most curious manner; young Pelicans 
