shelter 99 



We may better understand the importance of shelter if we con- 

 sider the two extremes: no appreciable shelter available; and a cover 

 composed of too-complete shelter. In the first instance we may con- 

 sider a large area of open farmland devoid of woodland or brush. 

 It may be of any type of fields— hay, pasture, or farm crops— they 

 are all alike to the grouse in that they are almost completely devoid 

 of shelter of the kind required by these birds. Of course, this type 

 of range produces no grouse, can maintain no grouse, even though 

 many grouse foods ( herbaceous ones ) might be present in quantity, 

 and other needs may be present. Without shelter, grouse cannot in- 

 habit an area. On the other extreme we have the situation where 

 shelter cover is so dense and extensive that little of it can be utilized 

 by grouse. Extensive areas of pure stands of some conifers at cer- 

 tain age periods are in this condition. The birds are able to use only 

 the exterior margins and very rarely will penetrate more than three 

 hundred feet into such an area ( Edminster, 1935 ) . Here again shel- 

 ter has proved to be a limiting factor for grouse, limiting by virtue 

 of excluding other needed components of the range. 



Between these two extremes we have all manner of variations in 

 shelter conditions and in the degree of limiting effect it has on 

 grouse populations. If shelter is excellent on a piece of grouse range, 

 food conditions may well be good also, in which case some other 

 factor would limit the numbers of grouse, possibly the saturation 

 point of four acres per bird. Generally this ideal state will not pre- 

 vail and the quality, quantity, and arrangement of the shelter com- 

 ponents of the range will play a considerable part in determining 

 the level of grouse abundance. 



REFERENCES AND CITATION SOURCES ON RUFFED 

 GROUSE SHELTER REQUIREMENTS 



Bump, Gardiner. Analysis of Certain Cover Requirements of the Ruffed 



Grouse in New York State, Trans. Third N. A. WildUfe Conf., 1938. 

 Edminster, F. C. The Effect of Reforestation on Game, Trans. 21st Am. Game 



Conference, 1935. 

 Fisher, L. W. Studies of the Eastern Ruffed Grouse in Michigan, Mich. State 



College, Tech. Bui. 166, 1939. 

 Leopold, Aldo. Game Management, 1933. 

 Palderboer, Emmett B. Cover Requirements of the Eastern Ruffed Grouse 



in Northeast Iowa, Iowa Bird Life, XII, pp. 50-55, 1942. 



