The Audubon Societies 



there are no sueh arl»itrary dixisions made \>y man Birds know only the 

 dividing lines set by Nature's own hand — lines of temperature, of altitude, 

 of humidity or aridity, which mark out areas suitable for the existence of 

 species of certain habits and vigor. Man, indeed, has some powsr to interfere 

 with Nature's bounds, for he can, at will, drain marshes, cut down forests, 

 burn over vast tracts, or plant extensive fields with grains, crops, or orchards 

 of fruit. He can even bring water into the desert and change the very face 

 of Nature; and so, as we study the birds' ma]) of America, we must all the 

 time keep in mind what man is doing. 



Let us now make a third outline, to help us remember what the map of the 

 birds is like, and then try to answer a few questions as to what man is doing 

 in his conquest of nature. 



Outline of Faunal .\reas of Distribution in North America, according to 

 Dr. J. A. Allen and Dr. C. Hart Merriam 



Realm Region Sub-region Province Sub-province District Fauna 



. . ( Barren ground 



•^^•^'"^ I Alaskan-Arctic 



Isotherm of J2°. Tree-1 



North 

 American 



North Temperate 



Cold Temperate. 



lAl 



Lsit 



Hudsoniaii 

 dian 

 eutian 

 Sitkan 



Warm 



Temperate 



. , ( Appalachian f Alleghanian 



I'd ', A,,.,,„ ,;.,.,;.,., < Carohnian 



( Great plains 

 Upper Sonoran-< Great basin 



( Pacific coast 

 Lower Sonoran 



(.Louisianian 



( Faunas not yet 

 I worked out 



American 



Tropica 



oi 70 



(Central \ fTamaulipan 



American j | St. Lucas 

 Antillean Floridian 



1. Notice that there is little variation throughout the arctic realm, either in climate 

 or topography, and that the majority of forms found there are circumpolar in distribution . 



2. Notice that the cold temperate subregion is also an east to west division, being 

 made up of transcontinental coniferous forests, except on the Pacific coast. Compare 

 the temperature of Newfoundland with that of Lake Superior, Athabasca and Alaska. 



3. Notice that the warm temperate subregion is more greatly diversified than the 

 cold temperate. 



4. Notice that the humid and arid provinces which make up the warm temperate 

 subregion, form a north to south division along the looth meridian, the dividing factor 

 being the amount of annual rainfall. 



5. Notice that the lower Sonoran subprovince comprises mostly open plains and 

 deserts in the western United States. 



6. Notice that there are two main highways from the American tropical realm into the 

 North American and arctic regions. These are through Central America and The Antilles. 



7. See Exercises, V, VI, VII, Bird-Lore. 



