INTRODUCTION. 



9 



extended in two long, slender filaments of the hyoid bone which curl 

 up around the back of the skull and, while they commonly stop 

 between the eyes, in some species they pass around the eye (fig. 2, b), 

 but in others enter the right nasal opening and extend to the end of 

 the beak (fig. 2, a). In this last case the tongue is practically twice 

 the length of the head. Posteriorly this organ is inclosed in a muscu- 

 lar sheath by means of which it can be extruded from the mouth to 

 a considerable length, and used as a most effective instrument for 

 dislodging grubs or ants from their burrows in wood or bark. Hence, 

 while most birds have to be content with such insects as they find on 

 the surface or in open crevices, the woodpeckers devote their energies 

 to those larvae or grubs which are beneath the bark or even in the 

 heart of the tree. They locate their hidden prey with great accuracy 

 and often cut small holes directly to the burrows of the grubs. In 



Fig. 3. — Wood from which woodpecker has extracted insect. 



figure 3 the grub had eaten a burrow through the heart of a maple 

 sapling, but its position was accurately determined by the bird, which 

 then cut through the solid live wood until it reached the burrow and 

 extracted the insect. 



In the United States, exclusive of outlying possessions, there 

 are about 45 species and subspecies of this family, most of which are 

 of decided economic importance. As a family they are much less 

 migratory than most other birds, and a majority of the species occupy 

 the same range throughout the year, which adds materially to their 

 value to farmers. Their food consists so largely of wood-boring 

 grubs, hibernating insects, and insects' eggs and pupae that their 

 supplies do not fail even in the coldest weather. 



The present paper is based upon the examination of 3,453 stom- 

 achs of woodpeckers representing 16 species and nearly twice as 

 many subspecies, taken in all parts of the United States, with a few 

 from Canada. In the following table the species are arranged in the 



