196 



NATURALIST'S GUIDE TO THE AMERICAS 



summer visitants. Out on the desert 

 proper, far from water, one may find 

 here and there a pair of Say phoebes 

 nesting in some rocky ravine or mine 

 tunnel; rock wrens associate with the 

 chuckwallas in the bare broken rock 

 masses; cactus wrens build their con- 

 spicuous covered nests in clumps of the 

 most prickly cactus. . . . 



The Le Conte thrasher which, owing 

 to his wary nature and sand-toned color 

 was formerly "considered the rarest of 

 southwestern birds," is heard in the 

 cool morning hours on the desert, while 

 pairs of ravens and several species of 

 woodpeckers are also to be noted. 



Very few typical animals of the 

 chaparral belt extend their range above 

 an elevation of 4000 ft. in the Sierras. 

 At this altitude one finds blue-fronted 

 jays, western robins, the sierra junco 

 and several species of woodpeckers. 

 In the red fir forests above elevations 

 of 7000 ft. will be found ruby-crowned 

 and golden-crowned kinglets, nuthatches 

 of three species, two species of sap- 

 suckers, the Townsend solitaire and near 

 timberline, the famous Clarke nut- 

 cracker. Characteristic mammals in- 

 clude certain species of chipmunks 

 (Eutamias), the Sierra red squirrel 

 (Sciurus douglasii albolimbatus), Sierra 

 marmot (Marmota flaviventris subsp.), 

 porcupine (Erethizon epixanthum} and 

 bushy-tailed wood-rat (Neotoma cinerea 

 subsp.). 



Above timberline, at about 10,000 ft. 

 altitude and for some 1000 or 2000 ft. 

 farther, plant life of dwarfed types con- 

 tinues, and here the rosy finch and rab- 

 bit-like cony find their permanent 

 abode. They, with other similarly 

 restricted species characterize the Al- 

 pine-Arctic Zone. 



III. PRESENT BIOTIC CONDITIONS 



Much of the Pacific Coast mesophytic 

 forest of which the redwood (Sequoia 

 semper vir ens) is the characteristic tree, 

 is still in its natural state though there 

 has been much cutting. As the redwood 

 stump sprouts, a second growth rapidly 

 appears. 



The great central valleys which were 

 once steppe or grassland areas are now 



largely under cultivation. Much is now 

 irrigated farm land and the remainder 

 is heavily grazed. 



The great chaparral belt of the foot- 

 hills of the Sierras is little disturbed 

 except for areas cleared for fruit land 

 and the modification due to extensive 

 grazing. 



There has been extensive lumbering 

 in the main forest belt, inroads having 

 been made especially on the sugar pine 

 and western yellow pine, the trees of 

 greatest commercial value. Most of 

 the mountain districts have been grazed 

 by cattle and many mountain meadows 

 have been modified due to extensive 

 grazing of sheep. Exotic forage plants 

 are to be found in unlocked for places. 

 Perhaps the least modified areas in the 

 northern part of the state are to be found 

 in Del Norte County and in eastern 

 Siskiyou and western Modoc counties 

 in the area known as the "lava beds" 

 or "devils garden." Even these areas 

 are frequented by hunters and cattle- 

 men. 



The streams of the southern and 

 eastern portions of the Sierras and of 

 southern California have been diverted 

 for irrigation purposes. Pollution of 

 many streams by sawdust and mine 

 refuse and to some extent by sewerage 

 is only partly checked by laws. As 

 a consequence the fauna of some of 

 them is quite completely changed. 



The Pacific slope of southern Califor- 

 nia is largely under cultivation and 

 fauna and flora greatly modified. The 

 deserts of the southwest are cultivated 

 wherever water is available. How- 

 ever, large areas of the desert are still 

 unmodified except as the result of 

 grazing. 



The grizzly bear, burro deer, Colum- 

 bian sharp-tailed grouse, and trumpeter 

 swan are now extinct in California and 

 the elk, pronghorn antelope and bighorn 

 sheep are candidates for extinction. 

 The sturgeon has practically disap- 

 peared from streams, and many game 

 species are greatly reduced in numbers. 



There has been extensive planting of 

 exotic plants and trees in southern 



