PLATE PAGE 



51. Nests of California Least Vireo and Tolmie Warbler 728 



52. American Dipper 729 



53. Western Mockingbird and California Shrike; Dotted Canon Wren and San 



Joaquin Bewick Wren 731 



54. Western House Wren and nest sites 733 



55. Nests of Western Robin and Townsend Solitaire 734 



56. Black-billed Magpie and Mountain Bluebird 735 



57. Mountain Lizard, Western Fence Lizard and California Whip-tailed Lizard 736 



58. Western Skink and alligator lizards 737 



59. Valley Gopher Snake and Pacific Rattlesnake 739 



60. Some amphibians of the Yosemite region 741 



Maps, Colored 

 (at end of half-tone plates) 



61. Profile of Yosemite section showing relation of life-zones to altitude and slope 



62. Map showing life-zones of Yosemite section 



Figures in Text 



FIGURE page 



1. Zonal restriction of certain mammals 5 



2. Zonal restriction of certain breeding birds 7 



3. Sample census sheet 23 



4. Snout of Yosemite Mole 43 



5. Fore foot of Yosemite Mole and of Sierra Nevada Pocket Gopher 44 



6. Zonal distribution of shrews 48 



7. Pacific Pallid Bat 61 



8. Mexican Free-tailed Bat 62 



9. Sierra Least Weasel, Mountain Weasel and Pacific Mink 87 



10. Heads of white-footed mice 105 



11. Zonal distribution of white-footed mice 107 



12. Tails of Alexandrine Roof Rat, and of Streator and Gray Bushy-tailed wood rats 116 



13. Streator Wood Rat 117 



14. Nesting quarters of Streator Wood Rat in log 119 



15. Gray Bushy-tailed Wood Rat 121 



16. Tails of Yosemite Meadow Mouse and Sierra Cantankerous Meadow Mouse 123 



17. Burrow-system of Mariposa Meadow Mouse 128 



18. Enlarged section through part of preceding 129 



19. Zonal distribution of meadow mice 130 



20. Sierra Cantankerous and Yosemite meadow mice and Mountain Lemming Mouse 131 



21. Willow association at head of Lyell Canon 132 



22. Method of work of mole 136 



23. Method of work of pocket gopher 137 



24. Zonal distribution of pocket gophers 139 



25. Cartoon suggesting relation of pocket gopher work in high mountains to accumu- 



lation of fertile sediments in lowlands 143 



26. Quill of Yellow-haired Porcupine 152 



27. Zonal distribution of squirrels and marmot 163 



28. Zonal distribution of chipmunks 178 



29. Sierra Chickaree 205 



30. Sugar pine cones as worked upon by Sierra Chickaree 206 



31. Kitchen middens: remains of cones of Jeffrey pine 207 



32. Sierra Flying Squii-rel 212 



33. Head of California Jack Rabbit 223 



[xvii] 



