Divergent estimates of herd-wide caribou calf survival: ecological factors and methodological biases

Population monitoring is a critical part of effective wildlife management, but methods are prone to biases that can hinder our ability to accurately track changes in populations through time. Calf survival plays an important role in ungulate population dynamics and can be monitored using telemetry and herd composition surveys. These methods, however, are susceptible to unrepresentative sampling and violations of the assumption of equal detectability, respectively. Here we capitalized on 55 herd-wide estimates of woodland caribou (Rangifer tarandus caribou) calf survival in Newfoundland, Canada using telemetry (n = 1,175 calves) and 252 herd-wide estimates of calf:cow ratios (C:C) using herd composition surveys to investigate these potential biases. These data included 17 herd-wide estimates replicated from both methods concurrently (n = 448 calves and n =17 surveys) which we used to understand which processes and sampling biases contributed to disagreement between estimates of herd-wide...