TWELVE WINTER BIRDS. 303 



Like the snow-bird, the cross-bill belongs to the 

 great family of Fringillidce, whose members are com- 

 monly known as finches and sparrows all having a 

 thick cone-shaped beak for cracking 



seeds. But the beak of the cross-bill 

 Cross=bill. 



has, in time, undergone a wonderful 

 change, or, in other words, has become adapted to the 

 habits of the bird. For, instead of the two mandibles 



Fig. 84 American Cross-bills. (After Coues.) 



meeting on a level as in other finches, the upper 

 curves down to the right of the lower, which at the 

 same time curves upward. In this way they partly 

 cross one another, thus giving rise to the common 

 name of the bird. 



The bill is thus fashioned to extract the seeds of 

 pines arid other similar trees from the cones, and the 

 cross-bills, by the great strength of the muscles of the 



