Approximately 1225 mule deer were on the area during 

 autumn 1960 when, as a result of good recruitment of fawns, 

 the population was probably at least somewhat higher than 

 during 1959 (Fig. 4.1). Relatively minor fluctuations in 

 population numbers occurred through autumn 1964. A major 

 population decline occurred during the severe winter of 1964- 

 65, reducing the 1020 deer entering winter to 715 deer (-30%) 

 by spring 1965. The number of deer remained stable through 

 spring 1967 and then started an increasing phase with the 

 addition of the large 1967 cohort. That increasing phase 

 lasted through spring 1971. High mortality during the severe 

 winter of 1971-72 reduced the 1130 deer entering winter to 665 

 survivors (-41%) by spring 1972. From that point, a slow, 

 gradual decline in deer numbers through 197 6 occurred despite 

 good weather and forage conditions during 1973-1975. 

 Beginning with high survival of the 1978 fawn cohort, the mule 

 deer population then increased through early winter 1983, 

 reaching an autumn peak of 1715 deer and an early winter peak 

 of 1545 deer. High mortality of fawns and relatively high 

 mortality of adult females during winters 1983-84 and 1984-85 

 reduced total numbers of deer to 870 by spring 1985. Although 

 initial production of fawns was poor during 1985, those alive 

 during autumn survived well and a population increase started 

 that has lasted through early winter 1987. 



The total mule deer population varied by up to 3-fold 

 within any season from low to high during 1960-1987 (Fig. 

 4.1). Maximum difference between the lowest spring (390 deer 

 in 1976) and highest autumn population estimates (1715 deer in 

 1983) was 4.4-fold. Numbers of adult females fluctuated less 

 than other sex/age groups, varying about 2.75-fold within 

 seasons and 3.1-fold between lowest spring numbers and highest 

 autumn numbers (Fig. 4.2). Numbers of adult males fluctuated 

 from about 3.5 to 4-fold seasonally, and 6-fold from lowest 

 spring to highest autumn population (Fig. 4.3). The number of 

 fawns in the population varied about 5-fold in autumn and 

 early winter populations and about 13.5-fold for recruited 

 fawns in spring (Fig. 4.4). Highest number of fawns in autumn 

 was about 17.5 times greater than the fewest recruited fawns 

 in spring. Trends in fawn recruitment preceded trends in 

 adult populations by one year (Figs. 4.2, 4.3, and 4.4). 



During 1960-1987, the mule deer population varied in 

 density from a low of 1.4/km 2 during spring 1976 to a high of 

 6.2/knr during autumn 1983. Because deer were not observed on 

 17% of the study area during any aerial surveys, ecological 

 density was higher than absolute density. For generally 

 occupied deer habitat, density was 1.7/km 2 during the 

 population low and 7.5/km 2 during the high. Deer numbers and 

 density were actually higher at birth pulse during mid-June 

 (up to 9/km 2 ) , but we did not consider fawns effectively added 

 to the population until weaned, just prior to the hunting 



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