SHELTER AND HOUSING MATERIAL CO ACTIONS 



111 



significant, but these are naturally more complex and at present less 

 understood. 



SHELTER AND HOUSING MATERIAL COACTIONS 



The importance of plant shelter has been emphasized chiefly in 

 connection with game management, especially that of game birds. 



Fig. 23 



Fig. 24 



Fig. 23. — Meadow mouse (Microtus drummondi, A. & B.) runway at Churchill, 

 Manitoba. The run stands out most clearly where it passes through the water 

 in the center of the upper section. It also shows as a dark area at the right 

 center of the lower section where it passes through dense sedges at the margin 



of the depression. (Photos by V. E. Shelford.) 



Fig. 24. — Woodpecker, Colaptes chrysoides (Malh.), holes in Cereus giganteiis, 



Tucson, Arizona. (Photo by Edith Clements.) 



Plant cover for shelter during sleep and rest, and during summer heat 

 and winter cold, is a major requirement for game production, and 

 especially for the nesting period. Leopold (1933) describes these in 

 detail for the quail, and brings out the importance of the right density 

 of cover to permit taking flight, of bushes of the forest-edge habitat 

 of the quail to afford refuge when snow is deep, and of open grasslike 



