DISTRIBUTION AND RELATIVE ABUNDANCE 53 



As stated previously, it is not within the scope of this report to undertake a detailed dis- 

 cussion of subspecific relationships. Therefore, only a very generalized picture is presented. 

 For each race, the type locality* is marked in figure 1. It is probable that the area of former 

 range throughout the Mississippi watershed, east of the Great Plains was largely occupied by 

 umbellus, while in Colorado, umbelloides was the predominant form. An important aspect 

 of the distribution of these races is that between no two does a clear cut line of demarcation 

 exist. Rather, one finds zones of intergradation where individuals of one subspecies occur side 

 by side with those of another and where birds of intermediate coloration are also common. 



The subspecies involved in such zones of intergradation are. in general, those whose basic 

 ranges are adjacent. In the case of togata, however, certain interesting variations exist. In the 

 East, it invades the area occupied by umbellus in the form of a long arm reaching down the 

 Appalachian Mountains where Transition or Canadian conditions occur. In the West, it ex- 

 tends along the eastern margin of the Rockies through Montana and Wyoming, and in British 

 Columbia, it crosses the mountains, inlergrading with sabini in the lower Fraser Valley and 

 with umbelloides northward, at least to the Cariboo district'". This suggests the possibility 

 that, from the standpoint of evolution, togata may represent the original race while the others 

 are more recent modifications. 



DISTRIBUTION AND RELATI\ K ABUNDANCE^ 



The ability to occupy such an extensive range illustrates a highly important element in 

 grouse ecology, namely, that the species is typical of sub-climax forest vegetation — shrubs, 

 second growth and forest edges. Accordingly, it finds suitable conditions associated with the 

 developmental stages of several climax types (biomes) rather than being restricted by the 

 limits of any particular one^. From Alaska and northern Canada, where it frequents the 

 spruce timber side by side with the spruce grouse, it seems equally at home in the redwood 

 forests of the Pacific Coast, the aspen groves of the prairie country, and the mixed woods of 

 the Northeast. Furthermore, early records indicate considerable populations to have inhabited 

 the hardwood swamps of Indiana and Ohio, and Audubon"^ even states he encountered these 

 birds in the canebrakes of the Mississippi. 



At the same time its distribution within this teriitoiy is far from uniform. Such a range 

 of necessity includes a host of local areas unsuitable to grouse but impossible to indicate on 

 a small scale map such as figure 1. Furlhermorc. the lialiitats in which the bird is found run 

 the gamut from good to poor, resulting in wide variations in relative abundance irrespective 

 of fluctuations associated with cyclic behavior. The following discussion of these features is 

 divided into two parts dealing with the range of the species in general and with New York 

 State respectively. 



Entire Range 



Conditions approaching the optimum for grouse* are found mainly across southern Canada, 

 northern Minnesota, northern Wisconsin, northern Michigan and south through New England. 

 New York, northern Pennsylvania and portions of the Alleganies I figure 31. Even here, 

 however, are many areas unfavorable to grouse. British Columbia and western Alberta, in 

 particular, present a complex interspersion of timbered valleys and alpine peaks — the one 

 supporting grouse, the other not. Along the edge of the prairies in southern Alberta and 



* See discussion under Taxonomy, p. 47. 

 A Bv Robert W. Darrow. 

 t See also Pilelka"". 

 t Sec Chapter HI. p. 110, and IV, p. 229. 



