COLOR AND IIAUXT AND IIABTT. 41 



Pacilic coa.st races are dai-ker or iiii>re lieavily streakc;! 

 or ImrrL'il tlian any of their eoiiii^eners. It is of iiiipor- 

 tanee to ol)serve that these dilfereuees are shown l)y 

 young ])inls in fresh pliiniaoe — evidence that the charac- 

 ters acquired through cHniate have ])een inherited. 



There are many similar cases, but some species seem 

 more easily affected than others, and throughout their 

 ranges are markedly alfected l;y the conditi(jns under 

 which tlicy live. Thus we have nine races of Screech 

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



These races, or snbspecies, are species in process of 

 formation. The extremes are still connected hy inter- 

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

 intermediates should disappear, the extremes would then 

 be left as distinct species. 



Color and JLiind and Ilalj'd. — The relation of a 

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

 ject. Any attempt at its explanation should l)e based on 

 so exact a knowledge of XXx^fad^ 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 adefpiate knowledge of the bird's habits. I 

 shall speak of only four classes of colors ; they are 

 protective^ deceptive^ recognition^ and sexual colors. 



Protective cohjrs render a bird inconspicuous in order 

 that it may escape its enemies. Deceptive colors render 

 it inconspicuous in order that it may more easily ap])roach 

 its prey. In both cases the bird should harmonize in 

 color with its innnediate surroundings. 



A survey of the birds of the world sh<>ws that on the 

 whole this is true. Thus almost all ground-inhabiting 

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



