AKT,i9 CONCERNING BIRDS TONGUES — GARDNER 7 



Hawks, owls, and vultures have powerful rasping tongues, a 

 structure that does not seem to be based primarily on the funda- 

 mental pattern. For in most of these birds the ceratohyals, accord- 

 ing to Giebel,® are fused the greater part of their length except at 

 about the mid point, where by reason of failure of fusion a hole 

 is left. 



Parrots display an individuality of their own. In many of these 

 birds the tongue is broader at the tip than at the base, forming 

 almost a finger, with the anterior margin convex. It may be flat, 

 cupped, grooved, rolled into a tube, or even brush-tipped (figs. 

 70-73). 



Finally, without considering the various rudimentary tongues 

 there are a host of odd types scattered throughout the class Aves, 

 such as the curious feathered tongues of the toucans (fig. 87) ; that 

 organ as found in the puff-birds (fig. 83), the cuckoos, the flamingoes, 

 and the like. One is constantly impressed with the fact that no 

 reliable guess as to the tongue form can be made by the appearance 

 or function of the bill and that any generalization is a very un- 

 certain procedure. 



The color of the tongue is interesting only in passing. Usually 

 flesh colored, it may not be so, however, often taking the color of the 

 bill or assuming a color of its own. Thus it is black in the crow and 

 its allies ; has brown spots in some swallows ; may be entirely black 

 with white spines in that odd cuckoo, the road-runner {Geococcyx 

 calif ornianus) ^ or be almost entirely flesh-colored, mottled with 

 black, in other members of the same species. It is pink in the red- 

 billed Heermann gull {Larus heermanni) . It is said to be scarlet 

 in the black cockatoo. Still again a light blue is seen. Some of 

 the hawks, as the marsh hawk {Circvs hudsonius), have the posterior 

 end and the spines this color. 



Out of this confusing multiplicity of form it seems possible to 

 make certain groupings as to function and adaptation. And if 

 this is done one finds approximately eight natural groups are 

 formed : 



1. An omnivorous diet is productive of a rather generalized pat- 

 tern. This includes the great majority of tongues found in the 

 Passeri formes, as has been described. The chief adaptive feature 

 lies in the presence of the posterior marginal spines. The tongue is 

 capable of being depressed at the tip and elevated posteriorly. 

 When worked rapidly backward and forward it can be used to 

 force resistant food down the throat. The efficacy of this is most 

 astonishingly manifest if, for instance, a bit of cloth be fed to a 

 nestling. In such an instance it is only with difficulty that the 

 cloth can be withdrawn from the throat without injury to the bird, 

 so eagerly is the tongue with its spines used to resist the effort. 



