384 Bird - Lore 



A birds' map of America, let us remember, would ha\-e no lines of division 

 into states and territories, but, rather, imaginary lines indicating roughly 

 where temperature and moisture vary beyond certain limits; when snow and 

 ice, for example, give way to coniferous forests, and these in turn, to tillable 

 land and milder climate, and so on, through constantly changing conditions, 

 from the Arctic region to the tropics. 



Everywhere on this map of the birds, instead of cities and towns, would 

 be marked different food-supplies and the location of water. The great va- 

 riety of these supplies might lead one wholly unfamiliar with birds to suspect 

 that a great variety of birds also must exist, which is exactly the case although 

 the inference should not be drawn that external conditions, or environment, 

 are the cause of this striking variation. 



Without attempting to discover the causes of variation, which would be 

 far from our purpose, let us begin to study into the subject of the adaptation 

 of different birds to different foods in the locaHties which they frequent. 

 Food, as we know, is the first necessity of any newly hatched fiedghng, and 

 we may therefore go quite naturally from the last exercise, in which the kinds 

 of food-supplies available for birds occupied our attention, to the bills of birds 

 which are the chief tools of the latter for getting food. 



It would be entertaining and very much worth while to pass in review the 

 bills of all the different kinds of birds in the world, if we had time. Since this 

 is not practicable, let us make a list of the species that have been described in 

 the Educational Leaflets during the last two years or so, and study them in 

 connection with the adaptation of bills to food. 



Such a list, systematically arranged would include the 



Order Name of Species. Order Name of Species. 



I Tufted Puffin. XVI Chimney Swift. 



Crested Auklet. Ruby-throated Hummingbird. 



V Emperor Goose. XVH Horned Lark. 



VII White Egrets. Yellow-headed Blackbird. 



Green Heron. Rosy Finch. 



IX Least Sandpiper. Alaska Longspun 



Semipalmated Sandpiper. Cedar Waxwing. 



Spotted Sandpiper. Catbird. 



Hudsonian Curlew. Brown Thrasher. 



X Bobwhite. Carolina Wren. 



California Quail. White-breasted Nuthatch. 



Ruffed Grouse. Red-breasted Nuthatch. 



Willow Ptarmigan. Tufted Titmouse. 



X\' Hairy Woodpecker. 



Downy Woodpecker. 



These species offer sufficient variation in bills and food-habit to clearly 

 illustrate the principle of adaptation. 



The first thing to keep in mind is the use of the bill. At first sight almost 

 anyone might think that the bill of a bird is a horny nose or the hardened lips 



