COLOB AND II AUNT AXD HABIT. 41 



Pacific coast races are darker or more heavily streaked 

 or barred than any of their congeners. It is of impor- 

 tance to observe that these differences are shown by 

 young birds in fresh plumage — evidence that the charac- 

 ters acquired through climate have been inherited. 



There are many similar cases, but some species seem 

 more easily affected than others, and throughout their 

 ranges are markedly affected by the conditions under 

 which they live. Thus we have nine races of Screech 

 Owl, eleven of Horned Lark, six of Junco, etc. 



These races, or subspecies, are species in process of 

 formation. The extremes are still connected by inter- 

 mediate or natural links, but if, through any cause, these 

 intermediates should disappear, the extremes would then 

 be left as distinct species. 



Color and Haunt and Habit. — The relation of a 

 bird's color to its haunts and habits is a complex sub- 

 ject. Any attempt at its explanation should be based on 

 so exact a knowledge of the facts in the case, that I can not 

 too strongly emphasize here the necessity for observations 

 in the field. Only a close study of the living bird will 

 justify us in advancing theories to account for its coloration. 



Many explanations have been offered to account for 

 certain colors and markings of birds, but often, I fear, 

 without adequate knowledge of the bird's habits. I 

 shall speak of only four classes of colors ; they are 

 protective, deceptive, recognition, and sexual colors. 



Protective colors render a bird inconspicuous in order 

 that it may escape its enemies. Deceptive colors render 

 it inconspicuous in order that it may more easily approach 

 its prey. In both cases the bird should harmonize in 

 color with its immediate surroundings. 



A survey of the birds of the world shows that on the 

 whole this is true. Tims almost all ground-inhabiting 

 birds, such as Snipe, Plover, Quail, Grouse, Sparrows, 



