The combination of information available on fawn 

 survival, forage production, and antler size (deer condition) 

 indicated that poor fawn survival during 1973-1975 did not 

 result from poor forage conditions or poor physical condition 

 of the deer population. 



Effect of Coyote and Alternate Prey Populations on Fawn 

 Mortality 



Fawn survival rates during 1976-1987 were influenced by 

 coyote predation which was influenced by alternate prey 

 population level. Especially for microtine rodents, 

 population level probably was related to vegetation 

 production. 



Coyote populations on the study area were estimated by 

 siren answer surveys and den area surveys (Pyrah 1984, Hamlin 

 et al . 1984). Siren-answer surveys were also conducted in the 

 Yellow Water Triangle, about 65 km south of our study area, 

 during 1972-1978 (Pyrah 1987). Although density estimates 

 were lower on prairie habitats of the Yellow Water Triangle 

 than our study area, coyote populations followed the same 

 trend during 1976-1978. Density estimates for 1976-1978 were 

 almost identical on the Yellow Water Triangle (Pyrah 1987) and 

 prairie areas immediately adjacent to our deer study area 

 (Pyrah 1984). This relationship was used to estimate siren- 

 answer values and coyote density for our study area during 

 1972-1975 (Fig. 5.8). 



E 



0.4 



0.3" 



w 



o 



I 0.2 



o 



O 



■_ 

 a> 



| 0.1 



3 



0.0 



Missouri River Breaks Study Area 

 Yellow Water Triangle Study Area 



Projected from data for the Yellow 

 Water Triangle Study Area 



1972 



1977 



Year 



1982 



1986 



Figure 5.8 



Coyote density, as determined by the siren- 

 answer survey, for the Missouri River Breaks and 

 Yellow Water Traingle study areas. 



139 



