EVOLUTION OF THE COLORS OF BIRDS. 203 



different methods in which recognition at a distance 

 may be effected. Thus one means is " by having the 

 general color more or or less strikingly contrasted with 

 the environment," as with crows, buzzards, bluebirds, 

 woodpeckers, etc. It seems hardly possible that colors 

 such as the complex patterns of the woodpeckers, for 

 example, can have been developed merely in order that 

 the general effect shall be in contrast with the environ- 

 ment. With the crows and blackbirds, however, which 

 habitually consort in flocks, it is quite possible that 

 means of recognition has been at least one factor in the 

 production of the black color. 



It is difficult in many instances to say definitely 

 whether a certain mark should be classed among those 

 which are useful for recognition at a distance or in close 

 flight. The white rump-patch and flash of scarlet serve 

 to distinguish the red-shafted flicker (Colaptes cafer) as 

 far as the bird can be seen, and the same may be said of 

 the superciliary stripe and wing bars of the varied robin 

 (Hesperocichla nmvia). The markings of Audubon's and 

 the yellow-rumped warblers (Dcndroica auduboni and D. 

 coronata) are especially good recognition features. They 

 are probably of more use near at hand than at a dis- 

 tance although they might be of service at tolerably long 

 range, and especially during migrations. These mark- 

 ings are most conspicuous just as the bird takes flight, 

 at which time the yellow rump patch and white mark- 

 ings of the tail combine in a pattern which irresistably 

 catches the eye. The meadow lark (Sturnella magna) 

 just as it settles down on the ground exposes the white 

 outer tail feathers, which do not appear as a rule either 

 when the bird is at rest or in flight. Allusion has al- 

 ready been made to the reddish under tail coverts of the 

 Calif ornian towhee (Pipilo fiiscus crissalis). As the 

 bird hops rapidly about among the bushes they are 



