The density of deer in a given area increased only within 

 certain limits, probably as influenced by the interaction of 

 parturition territoriality and other aspects of social 

 organization with the fixed habitat base. Most of the 

 increase in deer density on the study area from 1976 to 1983 

 was the result of deer occupying previously unused areas 

 rather than substantial increases within areas of preferred 

 habitat . 



The structure of the habitat in an area, as influenced by 

 topography and vegetation, probably influences maximum deer 

 density. Habitat structure and diversity also influenced the 

 available resources, including the quantity and phenology of 

 forage (Klein 1985) and the occurrence and adequacy of sites 

 to ameliorate harsh winter conditions. Hiding cover, 

 availability of alternate prey, and predator effectiveness can 

 also be influenced by topography and habitat structure. For 

 example, those deer that had home ranges bordering on the 

 river and reservoir were more vulnerable to coyote predation 

 during winter because of the ice, despite relatively good 

 forage conditions in those areas . 



Habitat structure probably also influences the number of 

 parturition territories that an area will support. The more 

 topographically and vegetationally diverse areas not only 

 supplied a more varied and long-lasting source of quality 

 forage, but more rugged terrain also provided a greater degree 

 of visual isolation of deer from each other. Thick timber can 

 produce visual isolation and succulent forage during late 

 summer and autumn, but forage quantity is generally reduced in 

 thick timber and that type does not provide quality forage 

 during spring because of delayed phenological development. 

 Relatively open areas, however, that contain many different 

 slopes and exposures as a result of closely interspersed 

 ridges and valleys can provide as effective of visual 

 isolation for parturient females as thickly timbered areas. 



The degree of visual isolation an area provides may 

 influence how many adult females an area can support before 

 aggression by parturient females results in emigration by 

 yearling females. Rugged, diverse "core areas" provide 

 habitat that will support the most females and fawns over the 

 greatest variety of environmental conditions. Beyond the 

 limits that those areas provide for non-conflicting 

 parturition territories, excess production must disperse to 

 areas that are unoccupied during the fawn-rearing period. 

 Such dispersal provides for maximal occupancy of the 

 environment . 



Based on comparison between our findings and data 

 available from studies on other areas in Montana, we 

 hypothesize that habitat structure also at least partially 



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