Understanding population vital rates is fundamental to the evaluation of conservation options for wolverines (Gulo gulo). We estimated survival rates and causes of wolverine mortality in trapped and untrapped populations within montane, boreal, and tundra environments using data from 12 North American radiotelemetry studies conducted between 1972 and 2001. Rates were based on data for 62 mortalities of 239 radiomarked wolverines. Mortalities included 22 wolverines that were trapped or hunted, 3 road or rail killed, 11 that were predated, 18 that starved, and 8 deaths of unknown cause. Annual survivorship rates were estimated for sex and age class using Kaplan-Meier staggered-entry techniques. Survival was substantially lower in trapped (<0.75 for all age-sex classes) than in untrapped (>0.84 for all age-sex classes) populations. Human-caused mortality was mostly additive to natural mortality for wolverines in a management context. Logistic growth rate estimates indicated that trapped populations would decline (λ ≅ 0.88) in the absence of immigration from untrapped populations (λ ≅ 1.06). We recommend a system of spatial harvest controls in northern, continuous populations of wolverines and reduction of harvest along with more spatially explicit conservation measures in southern metapopulations. JOURNAL OF WILDLIFE MANAGEMENT 68(3):493-502

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Most Dall's sheep (Ovis dalli dalli) population‐monitoring efforts use intensive aerial surveys with no attempt to estimate variance or adjust for potential sightability bias. We used radiocollared sheep to assess factors that could affect sightability of Dall's sheep in standard fixed‐wing and helicopter surveys and to evaluate feasibility of methods that might account for sightability bias. Work was conducted in conjunction with annual aerial surveys of Dall's sheep in the western Baird Mountains, Alaska, USA, in 2000–2003. Overall sightability was relatively high compared with other aerial wildlife surveys, with 88% of the available, marked sheep detected in our fixed‐wing surveys. Total counts from helicopter surveys were not consistently larger than counts from fixed‐wing surveys of the same units, and detection probabilities did not differ for the 2 aircraft types. Our results suggest that total counts from helicopter surveys cannot be used to obtain reliable estimates of detection probabilities for fixed‐wing surveys. Groups containing radiocollared sheep often changed in size and composition before they could be observed by a second crew in units that were double‐surveyed. Double‐observer methods that require determination of which groups were detected by each observer will be infeasible unless survey procedures can be modified so that groups remain more stable between observations. Mean group sizes increased during our study period, and our logistic regression sightability model indicated that detection probabilities increased with group size. Mark‐resight estimates of annual population sizes were similar to sightability‐model estimates, and confidence intervals overlapped broadly. We recommend the sightability‐model approach as the most effective and feasible of the alternatives we considered for monitoring Dall's sheep populations.