I estimated apparent survival (ϕ) and capture (ρ) probabilities, population growth rate (λ) and seniority (γ), and population size for adult Wood Turtles using Cormack-Jolly-Seber and other models. Over the course of 9 years 59 turtles were captured 125 times; these captures were compiled using year as the sampling period in analyses. RELEASE tests indicated my capture data were underdispersed (i.e., less variation than expected by chance). Estimates of ĉ derived from χ2 /df calculations were less than 1; the goodness of fit results by group (TEST 2 + TEST 3) yielded a chi-square value of 10.87 with 25 df. The MARK book (Cooch and White 2013, pg. 5 - 6) states “there is lack of unanimity on how to handle ĉ < 1 . . . set ĉ =1, and ‘hold your nose’”. Due to this ambiguity, the model ranking selection processes for my CJS, Pradel, and POPAN routines were also run with the c-hat adjusted to a diminished value of 0.75, as well as with c-hat = 1.0. The best supported models (based on AICc, ∆AICc, AICc weight) changed depending on the value of c-hat used.
So my question is: which sets of models (those with c-hat = 0.75 or those with c-hat = 1.0) should I accept and report?
Thank you for your help,
Steven