(Hamlin and Schweitzer 1979). The amount of time fawns spend 

 active with the doe increases as they get older. Thus, much 

 mortality of fawns on the area occurred after they passed 

 their most sedentary and cryptic stage ( Dood 1978, Riley 1982, 

 Hamlin et al . 1984) . 



General observations suggested that annual forage 

 conditions and the timing of forage desiccation influenced the 

 degree of coyote predation on fawns by altering activity 

 patterns of both females and fawns. For example, it appeared 

 that during dry years, females spent more time foraging away 

 from their fawn and may have produced less milk (Rowland 1944, 

 Thomson and Thomson 1953) because of difficulty in locating 

 succulent forage. At the same time, hungry fawns spent more 

 time foraging on their own, exposing themselves to observation 

 and attack by coyotes . 



Fawns normally spend some time foraging on their own 

 during all summers, and most are at least somewhat active 

 independent of the dam by about 1 August (Riley 1982). 

 Observations during the dry summers of 1983, 1984, and 1985 

 indicated that fawns were more active, independent of their 

 mothers, during the day than in previous years. Similarly, 

 data obtained by Dood (1978) and Riley (1982) indicated that 

 fawns began foraging about 1-2 weeks earlier during the 

 relatively dry summers of 1977 and 1980 than during 1976, 

 1978, and 1979. Fawns were born about 6 days later, on 

 average during 1977 and 1980 than during 1979, further 

 indicating abnormally advanced, independent foraging by 

 younger fawns during those dry years . These observations 

 would seem to justify the hypothesis that dry conditions 

 resulting in early desiccation and reduced quality of forage 

 result in behavioral changes in fawns that increase their 

 susceptibility to predation. Such a hypothesis can explain at 

 least some of the interaction between fawn mortality, forage 

 quality, and coyote predation rates; however, more extensive 

 data on fawn behavior during wet and dry summers and 

 relationships to predation rate are needed. 



Because coyotes are facultative rather than obligatory 

 predators on deer, alternate prey population levels also 

 played a major role in the relationship between forage 

 production and fawn mortality. Microtine population 

 irruptions coincided with years of high forage production and 

 abundant ground cover. The availability of abundant, easily 

 captured prey and its increased use as food by coyotes (Hamlin 

 et al. 1984) greatly reduced the intensity of coyote predation 

 on mule deer fawns during those years . The fact that fawn 

 survival during 1980 and 1981 was higher than expected based 

 on both forage conditions and microtine population levels, 

 probably reflected increased availability of deer mice and 

 lagomorphs during those years. Both of these groups were more 



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