Genetics of Mountain Lions 115sample size while minimizing the potential for movement out of the harvest zone or
death from natu ral mortality prior to or during harvest).
Our ability to use the mark- recapture technique for estimating the population size
of mountain lions in the Black Hills was hampered by the be hav ior of the species,
trou ble with maintaining enough marked animals during harvest seasons, and exten-
sive movements of individuals, in addition to other statistical issues (i.e., variation in
capture probabilities [Russell et al. 2012]). We had marked some mountain lions, es-
pecially juveniles but also some adults, that dispersed from the Black Hills region, as
well as some that died of natu ral causes during the harvest season. Also, it was difficult
to generate a reasonable sample of marked adult males owing to the skewed sex ratio
of the species in the Black Hills (the ratio of males to females was estimated at 0.42:1);
thus, estimates were generated for the population, even though sex- specific harvest
rates likely differed. Relative to the secretive nature of mountain lion be hav ior, and
despite comments we received suggesting that hunters were able to get to and harvest
any lion at any time throughout the Black Hills, we wondered whether multiple
captures to periodically replace radio collars, as well as other interactions with humans,
might have enhanced the ability of marked lions to evade harvest, at least by some,
maybe older, individuals. If so, the results of population analyses using these animals
would have affected the estimates of population size on an annual basis and thus would
have led to much variation; the results might have potentially inflated population es-
timates, because a lower number of marked animals would be removed from the
population.
In contrast to the use of marked (i.e., radio- collared) mountain lions to estimate
population size, the use of ge ne tics provided supportive evidence that the mountain
Table 7.6. Population estimates for mountain lions aged ≥2 years of age
(i.e., in de pen dent of females) in 2012 and 2013
2012 2013RadioDNA
RadioDNA
NMPH NMHH NMTH NMPH NMHH NMTHN 177 266 259 253 188 162 158 151
SE 36 72 70 68 44 39 37 35
Lower
95% CI
108 124 121 119 102 86 84 81Upper
95% CI
249 408 397 387 273 238 231 220Source: Juarez 2014.
Note: Estimates were derived using 2- sample Lincoln- Peterson with Chapman modification, from
radio- marked and DNA- marked mountain lions. Three DNA- marked estimates were derived: where natu ral
mortality occurred only prior to the harvest season (NMPH), a midpoint in which natu ral mortality occurred
during half the harvest season (NMHH), and natu ral mortality occurred throughout the harvest season (NMTH).