The tally of unduplicated females with COY is now accepted by the IGBC as the method to 

 monitor population trend in the PCA. Females with COY are readily visible and uniquely 

 identifiable. However, the tally is influenced by counting effort, seasonal cover, and the total 

 number of animals. A standardized and conservative counting approach has been adopted to 

 avoid duplication of females counted. These records have been maintained by the IGBST since 

 1973. Given a three-year breeding interval, a minimum adult female population is determined by 

 summing three successive counts, which produces a three-year moving average. The average 

 count for females with cubs observed during the period 1973-1982 was 12. This count suggests 

 an average of 36 adult females in the population during that time. 



Fortunately, the pessimistic predictions of the 1980s were unrealized. The models may have 

 been based on assumptions that were too conservative. Management strategies designed to 

 protect female grizzlies were largely successful which may have contributed to a reverse in the 

 population decline. Researchers became cautiously optimistic that a population increase was 

 occurring by 1987. Researchers calculated a rate of increase of 4.6% per year. 



The female with COY count has been steadily increasing since the late 1980s. For the 2001 field 

 season, a count of 42 was reported. This figure suggests an adult female population of over 100. 

 For the year 2001, the IGBST reported a minimum population estimate of 361. Mean litter size 

 appears to have returned to the same level as that for the pre-dump closure (2.0 cubs/litter). 



The female COY tally for Yellowstone National Park has actually remained stable while the 

 increase recorded is due to improved counting efforts in the GYE outside of the park. However, 

 the data suggest a GYE total population increase and the whole ecosystem population figure is 

 the key recovery parameter. A minimum population of 361 is greater than the pre-dump closure 

 population suggested as down-listing target in the initial recovery plan in 1982. The current 

 minimum estimate is also very conservative, and actual bear numbers are significantly higher. 

 The USFWS 1993 Recovery Plan established additional demographic criteria for recovery, 

 including females with cubs of the year, mortality limits, and occupancy requirements. Current 

 information on these parameters and their relationship to recovery plan goals are shown in 

 Tables 2 and 3. All of the regional demographic criteria are currently being met for this 

 population. 



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