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Summary 1. Neonate survival is a key life history trait, yet remains challenging to measure in wild populations because neonates can be difficult to capture at birth. Estimates of survival from neonates that are opportunistically captured might be inaccurate because some individuals die before sampling, resulting in data that are left truncated. The resulting overestimation of survival rates can further affect ecological inference through biased estimates of covariate effects in survival models, yet is not addressed in most studies of animal survival. Here, we quantify the effects of left truncation on survival estimates and subsequent ecological inference. 2. Vaginal implant transmitters (VITs) enable capture of ungulates at birth, yielding data without left truncation. The effects of left truncation on survival estimation were quantified using age-dependent survival models for VIT and opportunistically captured neonatal deer. Differences in daily survival rates (DSRs) and cumulative survival probability were calculated for the first 70 days of life. In addition, left truncation was simulated by removing fawns that died during the first 1 or 2 days of life from the VIT-caught sample, isolating the effect of left truncation. 3. Cumulative probability of survival during the first 70 days of life was overestimated by 7–23% for fawns caught opportunistically compared with those caught by VIT, depending on model design. Differences in DSRs were large at age 1 day, but had converged by age 30 days. Simulated left truncation resulted in overestimates of survival of up to 31%. Model selection and covariate coefficients were strongly affected by left truncation, producing spurious ecological inference, including changes to sign and/or magnitude of inferred effects of all covariates. 4. We recommend (i) every effort be made to capture neonates; (ii) consistent capture methods, using at least in part non-truncating techniques, be implemented across years and study areas; and (iii) exclusion of left-truncated data from survival estimates until DSRs converge with those calculated from non-truncated data. This work emphasizes the importance of accounting for left truncation in survival estimation for any species with strong age-dependent survival in order to prevent biased conclusions produced by sampling method rather than true ecological effects.

We examined the roles of sex and spatial scale in habitat selection by Alaskan moose Alces alces gigas. We GPS-collared 11 female and seven male adult moose in the Tongass National Forest, Alaska, USA, during 2002-2004. We predicted that adult male and female moose would be spatially separated outside of the mating season, consistent with hypotheses attributing sexual segregation among sexually dimorphic ruminants to allometric differences in body and gastrointestinal size, and resulting differential needs for nutrient requirements by the sexes (the gastrocentric hypothesis), and varying risks of predation (the predation hypothesis) between sexes, especially for females with young. We predicted that habitat selection would be similar between sexes during the mating season, but dissimilar and occur at different scales during periods of late gestation and lactation. We expected that during segregation, females would select for a higher percentage of forested cover and a higher edge density than mal...

Densely vegetated environments have hindered collection of basic population parameters on forest-dwelling ungulates. Our objective was to develop a mark—recapture technique that used DNA from fecal pellets to overcome constraints associated with estimating abundance of ungulates in landscapes where direct observation is difficult. We tested our technique on Sitka black-tailed deer (Odocoileus hemionus sitkensis) in the temperate coastal rainforest of Southeast Alaska. During 2006–2008, we sampled fecal pellets of deer along trail transects in 3 intensively logged watersheds on Prince of Wales Island, Alaska. We extracted DNA from the surface of fecal pellets and used microsatellite markers to identify individual deer. With genotypes of individual deer, we estimated abundance of deer with moderate precision (±20%) using mark—recapture models. Combining all study sites, we identified a 30% (SE = 5.1%) decline in abundance during our 3-year study, which we attributed to 3 consecutive severe winters. We determined that deer densities in managed land logged >30 years ago (7 deer/km2, SE = 1.3) supported fewer deer compared to both managed land logged

We investigated the influence of habitat use on the risk of death of Sitka black-tailed deer (Odocoileus hemionus sitkensis) on Heceta Island in Southeast Alaska, USA. A mosaic of even and uneven-aged forests covered much of the island and provided a model setting in which to assess relationships between habitat use and mortality of deer. We radiocollared and monitored 51 adult females, 11 adult males, and 19 young of the year. We compared risk of death with habitat composition, habitat distribution, topography, distances to features such as roads, and functional habitat characteristics such as seasonal forage biomass within 50-, 500-, and 1,000-m circular buffers around relocations of deer. Those buffers encompassed habitats used at scales of radio-locations, home ranges, and landscapes. We addressed hypotheses that related habitat composition and distribution to risk of death from malnutrition, predation, and hunting. Predation by wolves (Canis lupus) and malnutrition were the principal causes ...

Relatively little genetic variation has been uncovered in surveys across North American wolf populations. Pacific Northwest coastal wolves, in particular, have never been analysed. With an emphasis on coastal Alaska wolf populations, variation at 11 microsatellite loci was assessed. Coastal wolf populations were distinctive from continental wolves and high levels of diversity were found within this isolated and relatively small geographical region. Significant genetic structure within southeast Alaska relative to other populations in the Pacific Northwest, and lack of significant correlation between genetic and geographical distances suggest that differentiation of southeast Alaska wolves may be caused by barriers to gene flow, rather than isolation by distance. Morphological research also suggests that coastal wolves differ from continental populations. A series of studies of other mammals in the region also has uncovered distinctive evolutionary histories and high levels of endemism along the Pacific coast. Divergence of these coastal wolves is consistent with the unique phylogeographical history of the biota of this region and re-emphasizes the need for continued exploration of this biota to lay a framework for thoughtful management of southeast Alaska.