EVOLUTION OF THE COLORS OF BIRDS. 281 



being lost because it is so inconspicuous as to be of no 

 particular use? I fail to see that the bright markings in 

 this family can have been developed otherwise than by 

 sexual selection. In most cases the colors have been 

 transferred by inheritance to the female, but generally 

 in a more or less imperfect manner. Why the bright 

 colors, particularly of the crown patch, should be lost, 

 is even a more difficult question than how they were ac- 

 quired. Woodpeckers are not peculiarly exposed to the 

 attacks of rapacious birds or mammals, so the suppres- 

 sion of red could hardly have been due to the need for 

 protection. 



The white-headed woodpecker (Xenopicus albolarvatus) 

 is remarkable from the fact that there are no hybrid 

 feathers along the edge of the white marking. This 

 would seem to argue that the white head is due to some 

 constitutional weakness, rather than to the operation of 

 natural selection. It is probably a step in degeneration, 

 which may have been pressed into service by natural 

 selection as a recognition mark. Picoides, on the other 

 hand, together with Ceophlceus and Campephilus and 

 Sphyrapicus thyroideus are rapidly tending towards mel- 

 anism. 



Characteristic recognition markings are very prevalent 

 in the family, particular attention having already been 

 called to a number of examples in preceding pages. The 

 flickers (Colaptes) afford the best possible illustration of 

 these marks. As the flicker flies the first thing to arrest 

 the attention is the white rump patch, arid in connec- 

 tion with this the flash of yellow or scarlet from the 

 wings. Whether the characteristic round black spots on 

 the sides are a form of recognition mark or due to some 

 other cause is a very difficult matter to decide. The 

 black and red malar streaks in the eastern and western 

 races, respectively, might be held to be discriminative 



