Tree cavities are used as shelter and breeding nests by numerous avian and mammalian species. In cold environments, tree cavities are often proposed as the best winter nest choice because of the superior protection they offer from precipitation, wind, cold temperatures, and predators. As such, they represent a critical resource, which has the potential to limit population size of non‐excavating species. We assessed factors affecting site occupancy in the boreal forest by northern flying squirrels, a secondary user of tree cavities, and to identify which nest type is preferred during the colder days of the autumn–winter period. We trapped flying squirrels twice in 59 aspen‐dominated stands in the autumn period using low‐ (1.5 m above ground‐level) and high‐mounted (4 m) traps to determine site occupancy. A total of 85 individuals were captured on 2,880 trap‐nights. During the winter period, we radio‐tracked 26 individuals to 87 diurnal nests in 220 locations. None of the habitat variables considered (cavity availability, woody debris, and lateral cover) explained site occupancy. Detectability decreased with precipitation, and was lower using high traps than low traps. Both females and males used tree cavities (26%), external nests (39%), and ground nests (35%). In cold weather, females preferred ground nests, whereas males preferred external nests. Our results do not support the hypothesis that tree cavities represent a limiting factor to northern flying squirrels in cold environments. Instead, this species seems to be a generalist and is opportunistic, using a variety of nest types. Nevertheless, practices ensuring the persistence of large diameter live cavity trees, providing better insulative properties, are likely to increase the relative use of tree cavities as nest sites by northern flying squirrels. © 2011 The Wildlife Society.

The aim of the present study was to compare the long-term effects of two dietary approaches on changes in dietary intakes, eating behaviours and body weight: (1) approach using restrictive messages to limit high-fat foods (low-fat intake; LOFAT); (2) approach emphasising non-restrictive messages directed towards the inclusion of fruits and vegetables (high intake of fruits and vegetables; HIFV). A total of sixty-eight overweight or obese postmenopausal women were randomly assigned to one of the two dietary approaches. The 6-month dietary intervention included three group sessions and ten individual sessions with a dietitian. Dietary intakes, eating behaviours and anthropometrics were measured at baseline, at the end of the dietary intervention (T¼6) and 6 months and 12 months after the end of the intervention (T¼12 and T¼ 18). In the LOFAT group, energy and fat intakes were lower at T¼6 when compared with baseline and remained lower at T¼12 and T¼18. In the HIFV group, fruit and vegetable intakes increased significantly at T¼6 but were no longer significantly different from baseline at T¼ 12 and T¼ 18. Dietary restraint increased at T¼ 6 and remained higher than baseline at T¼ 18 in the LOFAT group while no significant change was observed in the HIFV group. At T¼6, body weight was significantly lower than baseline in both groups (LOFAT: 2 3·7 (SD 2·8) kg; HIFV: 2 1·8 (SD 3·0) kg) and no significant difference in body-weight change from baseline was found between groups at T¼ 18. We concluded that weight loss was similar at 1-year follow-up in both dietary approaches. Despite relatively good improvements in the short term, the adherence to a 6-month dietary intervention promoting high intakes of fruits and vegetables was difficult to maintain.Fruits and vegetables: Low-fat diets: Weight loss: Postmenopausal women

Dynamic N-mixture models have been recently developed to estimate demographic parameters of unmarked individuals while accounting for imperfect detection. We propose an application of the Dail and Madsen (2011: Biometrics, 67, 577–587) dynamic N-mixture model in a manipulative experiment using a before-after control-impact design (BACI). Specifically, we tested the hypothesis of cavity limitation of a cavity specialist species, the northern flying squirrel, using nest box supplementation on half of 56 trapping sites. Our main purpose was to evaluate the impact of an increase in cavity availability on flying squirrel population dynamics in deciduous stands in northwestern Québec with the dynamic N-mixture model. We compared abundance estimates from this recent approach with those from classic capture–mark–recapture models and generalized linear models. We compared apparent survival estimates with those from Cormack–Jolly–Seber (CJS) models. Average recruitment rate was 6 individuals per site after 4 years. Nevertheless, we found no effect of cavity supplementation on apparent survival and recruitment rates of flying squirrels. Contrary to our expectations, initial abundance was not affected by conifer basal area (food availability) and was negatively affected by snag basal area (cavity availability). Northern flying squirrel population dynamics are not influenced by cavity availability at our deciduous sites. Consequently, we suggest that this species should not be considered an indicator of old forest attributes in our study area, especially in view of apparent wide population fluctuations across years. Abundance estimates from N-mixture models were similar to those from capture–mark–recapture models, although the latter had greater precision. Generalized linear mixed models produced lower abundance estimates, but revealed the same relationship between abundance and snag basal area. Apparent survival estimates from N-mixture models were higher and less precise than those from CJS models. However, N-mixture models can be particularly useful to evaluate management effects on animal populations, especially for species that are difficult to detect in situations where individuals cannot be uniquely identified. They also allow investigating the effects of covariates at the site level, when low recapture rates would require restricting classic CMR analyses to a subset of sites with the most captures.

Background/Objectives: To compare the effects of two dietary approaches on changes in dietary intakes and body weight: (1) an approach emphasizing nonrestrictive messages directed toward the inclusion of fruits and vegetables (HIFV) and (2) another approach using restrictive messages to limit high-fat foods (LOFAT). Subjects/Methods: A total of 68 overweight-obese postmenopausal women were randomly assigned to one of the two dietary approaches. The 6-month dietary intervention included three group sessions and ten individual sessions with a dietitian. Dietary food intake and anthropometric variables were measured at baseline, at 3 months and at 6 months. Results: Energy density decreased in both groups after the intervention compared with baseline (HIFV, À0.3±0.2 kcal/g; LOFAT, À0.3 ± 0.3 kcal/g; Po0.0001). Although body weight decreased significantly in both groups after the intervention compared with baseline (HIFV, À1.6±2.9 kg; LOFAT, À3.5±2.9 kg; Po0.0001), women in the LOFAT group lost significantly more body weight than women in the HIFV group (P ¼ 0.01). In the HIFV group, the decrease in energy density was found to be an independent predictor of body weight loss. Conclusions: The LOFAT approach induces more weight loss than does the HIFV approach in our sample of overweight-obese postmenopausal women.