ABT.,19 CONCERNING BIRDS ' TONGUES GARDNER 9 



4. Flesh feeders or the birds of prey, including the owls, have 

 developed heavy rasping tongues. The anterior portion is often 

 very rough and hard and in some forms somewhat curled as in 

 eagles and lammergeiers. The posterior spines, which may be in a 

 single or multiple row, are stiff and hard. Opening to the surface 

 are ducts of many mucous glands the function of which is manifest. 

 A curious modification of form is seen in the deep trough-shaped 

 tongues of the vultures and the condor, which are armed with sharp 

 marginal spines (figs. 36-43). 



5. Where the food is probed for and consists largely of insects we 

 see the structure as exemplified by woodpeckers. Lucas '^ has dem- 

 onstrated an interesting correlation with diet. Flickers (fig. 14), 

 having made a departure from the regular fare and having taken to 

 an ant diet, are found to possess a blunt-tipped tongue with but two 

 or three reduced barbs, while the extensibility is greatly increased 

 and the whole dorsal tract (basihyal position) plentifully supplied 

 with minute spines to hold mucous. In these birds also the sub- 

 maxilliary salivary glands reach their maximum development, a 

 combination well adapted to catch ants. 



In Melanerpes (fig. 15), where the diet has become more gener- 

 alized, it will be found that the extensibility is reduced and instead 

 of spines at the tip there has been a conversion to vibrissae or hair- 

 like processes. 



Finally in the sapsuckers (fig. 16) the extensibility is reduced to 

 a minimum. The dorsal tract is bare of spines except posteriorly, 

 where it is widened into a shieldlike structure bearing papillae. At 

 the tip and along the lateral edges there is a fine brush of hairs 

 which serves well for capillarity but is ill adapted to spearing grubs 

 nor are many of these found in an analysis of stomach contents. 



Among this group should be classed the spearing and impaling 

 organs of the titmice, and nuthatches, already described. 



6. Seed and nut eaters have fleshy and strong tongues. In this 

 group are to be classed those of the typical parrots (fig. 17) and 

 finches (fig. 18). In parrots it has been described. In finches it is 

 cylindrical or tends toward that form and slopes from base to tip. 

 Since the ability of a bird to project the lower mandible is very lim- 

 ited the rolling of seeds in the act of husking would be difficult. 

 With the inclined surface of the tongue, however, acting as a sur- 

 face against which seeds may be rolled, this is actually accomplished 

 most dexterously. In many finches for reasons not entirely under- 

 stood the tongue is often scoop-shaped or even rolled into a semi- 

 tubular structure, as will be illustrated later. 



T Lucas, P. A. The Tongues of Woodpeckers. Bull. No. 7, U. S. Dept. of Agriculture, 

 Div. Ornith. and Mammalogy. 



43.316—25 2 



