80NGLESS BIRDS OF ORCHARD AND WOODLAND. 247 



either pass into the nostrils and so on in channels clown 

 toward the end of the upper mandible of the beak, or, turn- 

 ing to one side, coil themselves about the bony part of the 

 eyeball. These branches of the hyoid are enclosed in 

 sheaths which fit into a groove on the top of the skull. By 

 means of this apparatus the tongue may be extended so 

 that, in the Hairy Woodpecker, it may reach an inch and 

 a half be^^ond the end of the bill. The tongue is propelled 

 forward at need by powerful muscles, so that when the bird 

 has drilled to the burrow of a Ijoring beetle it can open the 

 beak slightly, protrude the tongue, spear the insect and 

 draw it out and into the mouth. Birds which possess such 

 implements for the destruction of boring insects must be 

 immensely serviceable to man, for borers are difficult for 

 man to control. 



The utility of Woodpeckers is now quite generally recog- 

 nized by foresters, and hj entomologists who study forest in- 

 sects. Dr. A. D. Hopkins, the most active and experienced 

 forest entomologist in the United States, is quoted by Dr. 

 E. P. Felt as asserting that Woodpeckers are the most im- 

 portant enemies of spruce bark beetles, and appear to be of 

 inestimable value to the spruce timber interests of the north- 

 east. Dr. Hopkins also states that Woodpeckers are the 

 principal enemies of the destructive sap-wood borers. 



It is sometimes argued that Woodpeckers are of little use 

 as protectors of trees, since they never dig into living wood. 

 This reasoning is based on an error, due to 

 lack of careful observation, Nuttall speaks 

 of a Flicker that dug a nest hole eighteen 

 inches deep in a green sassafras. Dr. Hop- 

 kins figures a section of a living tree in which 

 a hole four inches long, two wide, and five 

 deep had been made by Woodpeckers in their 

 search for Ijoring larvae. According to the Fig. 105.— Apine 

 annual wood rings around the entrance of the 

 cavity, the tree recovered and lived at least fifteen years after 

 the bird captured the borers. The work of Woodpeckers on 

 living trees does not ordinarily attract much notice. They 

 seldom need to dig far into live trees for borers, for most 



