B. DESCRIPTIVE LIST OF NORTH AMERICAN BIOTA (SOUTH TO 



CENTRAL MEXICO) 



BY V. E. SHELFORD, L. JONES AND L. R. DICE 



1. ARCTIC TUNDRA, OR BARREN GROUND 



BIOTA (ARCTIC TUNDRA OP 



CLEMENTS) 



Extensive areas in the northern part 

 of the continent have long cold winters 

 and little rainfall. In the more north- 

 ern localities the ground thaws only 

 at the surface and a growth of herba- 

 ceous plants springs up in the summer. 

 There are dense growths of grass, many 

 miniature shrubs, shown in black on 

 the map, considerable areas of high 

 tundra, especially in Alaska. Large 

 areas of perpetual snow are included. 



It supports muskoxen (Ovibos mos- 

 chatus subspp.), barren ground caribou 

 (Rangifer spp.), arctic hare (Lepus 

 arcticus group), arctic fox (Alopex spp.). 

 The chief local conditions are swamps 

 and ponds, which support hordes of 

 mosquitoes. 



The breeding birds 1 include the fol- 

 lowing: willow ptarmigan, rock ptar- 

 migan, white gyrfalcon, gray gyrfalcon, 

 gyrfalcon, black gyrfalcon, snowy owl, 

 horned lark, pallid horned lark, Green- 

 land redpoll, hoary redpoll, greater 

 redpoll, snow bunting, Lapland long- 

 spur, Alaska longspur, Smith's longspur, 

 Alaska yellow wagtail, and pipit. 



Breeding birds whose habitat is 

 limited to the presence of water, gen- 

 erally a local condition, include the 

 following: yellow-billed loon, Pacific 

 loon, red-throated loon, pomarine jae- 

 ger, parasitic jaeger, long-tailed jaeger, 

 red-breasted merganser, old-squaw, 

 Harlequin duck, Steller's eider, spec- 

 tacled eider, King eider, Pacific eider, 

 scoter, white winged scoter, snow goose, 

 white-fronted goose, whistling swan, 



1 English names conform strictly to the A. O. U. 

 Check-list, unless otherwise specifically noted. 



red phalarope, northern phalarope, 

 long-billed dowitcher, stilt sandpiper, 

 knot, purple sandpiper, pectoral sand- 

 piper, white-rumped sandpiper, Baird's 

 sandpiper, least sandpiper, red-backed 

 sandpiper, semipalmated sandpiper, 

 western sandpiper, sanderling, Hud- 

 sonian godwit, yellow-legs, buff- 

 breasted sandpiper, Hudsonian curlew, 

 Eskimo curlew, black-bellied plover, 

 golden plover, Pacific golden plover, 

 semipalmated plover, turnstone, ruddy 

 turnstone, and black turnstone. 



la. ALPINE STEPPE OR HIGH TUNDRA 

 (PARAMOS OP PENNELL) (APLINE SUM- 

 MITS, SHREVE) (APLINE MEADOW CLI- 

 MAX, CLEMENTS) 



Sedge, grass, and herb covered areas 

 in high mountains. The large mam- 

 mals include bighorn sheep (Ovis cana- 

 densis subspp.), and Rocky Mountain 

 goat (Oreamnos americanus subspp.). 

 Rosy finches and white-tailed ptarmigan 

 are characteristic birds. 



2. NORTHERN CONIFEROUS FOREST BIOTA 

 (NORTHERN MESOPHYTIC EVERGREEN 

 FOREST, SHREVE) 



"This extensive region is characterized 

 throughout by a pure or nearly pure 

 stand of needle-leaved evergreen trees, 

 among which deciduous trees are often 

 present either as minor components of 

 the forest or else as trees of lower 

 stature. Virgin stands of this forest 

 range from 60 to 125 ft. in height and 

 vary from open park-like formations to 

 heavy forest with a completely shaded 

 floor. The heaviest stands are almost 

 devoid of shrubby undergrowth, but the 

 more open ones are accompanied by 

 deciduous shrubs and under-trees. In 



GO 



