Table 3.
CH structure | Population estimate | Bias in population estimate | ||||||
5 | 4 | 3 | 2 | 1 | True | Remaining | ||
TRUE | 1 | 2 | 5 | 4 | 4 | 16.6 ± 0.9 | +3.7% | +3.7% |
Obs1 | 0 | 2 | 3 | 6 | 7 | 20.3 ± 2.0 | +27% | +35% |
Obs 2 | 1 | 1 | 1 | 4 | 8 | 23.9 ± 7.2 | +49% | +84% |
Obs 3 | 1 | 2 | 3 | 6 | 6 | 21.0 ± 2.8 | +31% | +31% |
Obs 4 | 0 | 2 | 2 | 9 | 7 | 22.8 ± 2.3 | +42% | +42% |
Obs 5 | 1 | 1 | 3 | 5 | 8 | 23.5 ± 4.5 | +47% | +56% |
Obs 6 | 0 | 3 | 2 | 6 | 9 | 22.8 ± 2.3 | +42% | +42% |
Obs 7 | 2 | 0 | 5 | 5 | 3 | 16.1 ± 1.3 | +0.6% | +7% |
Obs 8 | 3 | 0 | 2 | 5 | 8 | 23.2 ± 3.9 | +45% | +45% |
The CHs were based on 5 sampling occasions; CH structure shows how many times each snow leopard individual was seen (where the ‘5’ column indicates an individual was recorded in 5 capture events, and the ‘1’ column indicates an individual was only identified by the observer once). Based on each observer’s CH a population abundance estimate was derived using a closed capture-recapture model (mean ± SD; see methods). The bias in the mean estimate for the population is shown relative to the true population size (n = 16) and also relative to the number of unique individuals remaining in each observers’ CH after accounting for animals removed from consideration because of capture event exclusion (for observers 1, 2, 5 & 7 the number of unique individuals assessed was n = 15, 13, 15 & 15 respectively; see Table 1).