CHAPTEK V. 



THE A^OICE OF BIRDS.* 



Aside from the pleasure to l)e derived from the calls 

 and songs of birds, tlieir notes are of interest to us as 

 their medium of expression. ITo one wlio has closely 

 studied l)irds will doubt that they liave a language, limited 

 though its vocabulary may be. 



S(Vi(j. — S(jng is a secondary sexual character, generally 

 restricted to the male. With it he woos his mate and 

 gives voice to the joyousness of nesting time. In some 

 instances vocal music may be replaced by instrumental, 

 as in the case of the drumming wing-beat of the Grouse, 

 or the bill-tattoo of the Woodpeckers, both of which are 

 analogous to sono-. 



The season of song corresponds more or less closely 

 with the mating season, though some species begin to 

 sing long before their courting days are near. Others 

 may sing to some extent throughout the year, but the 

 real song period is in the spring. 



Many birds have a second song period immediately 

 after the completion of their postbreeding molt, but it 

 usually lasts only for a few days, and is in no sense com- 

 parable to the true season of song. This is heralded by 

 the Song Sparrow, whose s\\'eet chant, late in February, 



* See Witohell, The Evolution of Bird Song (I^Iacmillan Co.). 

 Biclinell, A Study of tlie Singing of Our Birds; The Auk (New York 

 city), vol. i, 1SR4, pp. GO-71, 126-140, 209-318, 323-332; vol. ii, 1885, 

 pp. 144-151, 249-2(12. 



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