The Audubon Societies 387 



list above, the Woodpeckers seem to use the bill most like a workman's tool. 

 We often hear this type of bill likened to a chisel, drill, or pick-axe, but 

 hidden away in the recesses of the skull is a still more remarkable tool, the 

 tongue, which darts like a spear, moves shavings out of a cavity like a brush 

 and, by means of its rough surfaces, in some cases, aids in trapping insect prey. 

 The tongue of a Woodpecker seeks food which the bill could not get at, and 

 brings it within reach of the strong mandibles, — a peculiarity of this wood- 

 boring group. Perhaps a more striking illustration of adaptation could not 

 be found, although the Swifts and Hummingbirds present very remarkable 

 examples of adaptation of bill to food habit. 



Look at the frail, tiny bill of the Swift, and the long, slender, tube-like 

 bill of the Hummingbird. One hawks through the air with closed mouth, 

 snapping up mites of insect-food, which it stores in its capacious mouth- 

 pouch; while the other probes flowers for insects and sweet juices, or, at times, 

 catches its food in the air and about leaves. 



The tongue of the Swift is small and not particularly noticeable but the 

 tongue of the Hummingbird is modified most wonderfully as well as the bill. 

 A study of the tongues and bills of Hummingbirds, together with the flowers 

 which form their chief source of food-supply, would reveal many strange 

 and unsuspected adaptations. 



The remaining species in our list belong to the Order of Perching Birds 

 (Passeres) , and among them are tree-loving as well as ground-feeding species. 

 The Finch and Longspur are seed-eaters, and consequently have the stout, 

 conical, seed-cracking form of bill. The Nuthatches have a rather long, taper- 

 ing, slender bill, suited to dislodging insect prey from the bark of trees, or of 

 hiding nuts and seeds in crevices and hacking it open with the bill, a peculiar 

 habit which has given them their common name. 



The Brown Thrasher has a somewhat unusual bill for a perching bird, in 

 that it is not only noticeably long but also decidedly curved, although not so 

 much so as that of our Western Thrashers. Newly hatched Thrashers have a 

 straight bill at first, just as young Flamingos do, a suggestive fact, indicating 

 that the food habit may change with the development of the bird. Perhaps 

 you can discover for yourselves whether this statement is true. 



And now, when you go outdoors and look at the trees with their waving 

 leaves and age-ringed bark, or at the seed-bearing herbs and berry- or nut- 

 bearing shrubs, or at small animals and the host of insects and invertebrate 

 creatures which crowd every nook and corner of nature, do not forget that 

 these make up the regular diet of a great variety of birds, that are fitted by 

 almost every device one might think of for getting these food-supplies rapidly 

 and easily. 



In general, the bill of a bird is formed on the principle of a cone, the tip of 

 which is capable of handling small food particles with great precision and 

 delicacy, while the base is built for strength to crush or grasp large particles. 



