260 The Unity of the Organism 







Let the current view be accepted that the song of pas- 

 serine birds is associated adaptively with the mating func- 

 tion. Even so, no one who has given careful attention to 

 the matter can have failed to recognize that with many 

 species much more singing is done than actual pairing and 

 breeding call for. I have kept almost daily notes for sev- 

 eral years on the singing of the Western Meadow Lark, 

 Sternella magnu neglect a, in the vicinity of La Jolla. The 

 birds are resident the whole year through, and as they come 

 familiarly around my home and laboratory, the observations 

 can be quite full. Although the breeding time is restricted 

 to late February, March, April, and sometimes May, there 

 is not a month in the year when songs may not be heard, 

 most of the time in full volume. Significantly, I believe, the 

 song is at its ebb during some weeks just before the nesting 

 period begins. Nor does the singing of the males seem to 

 be connected in any close way with mating. The birds do 

 not pair off closely and permanently, even for the breeding 

 season. Most of the singing, which occurs chiefly in the 

 morning and early forenoon and again toward evening, is 

 done while the singer is, more commonly than otherwise, 

 quite alone on some telephone pole or wire. And the mode 

 of singing does not change at all when mating begins. An- 

 other interesting fact about the singing of this species is 

 the considerable range of temperature and light conditions 

 over which the song is invariable, so far as these factors are 

 concerned. The song may be as full and frequent on 

 cloudy, misty mornings as on sunny ones; and over a con- 

 siderable range of temperature the song is quite independent 

 of the particular degree marked by the thermometer. 



While the song habits of this bird are undoubtedly some- 

 what exceptional in their looseness of correlation with mat- 

 ing and with environmental conditions, certain it is that 

 much this sort of thing is observable with several resident 

 species which I have observed. The house finch, Carpodacus 



